TY - JOUR TI - West Florida Shelf Circulation on Synoptic, Seasonal, and Interannual Time Scales AU - Weisberg, Robert H. AU - He, Ruoying AU - Liu, Yonggang AU - Virmani, Jyotika I. T2 - Circulation in the Gulf of Mexico: Observations and Models AB - This chapter contains sections titled: Introduction Background Synoptic Variability Seasonal Variability Interannual Variability Summary and Discussion DA - 2013/3// PY - 2013/3// DO - 10.1029/161gm23 SP - 325-347 ER - TY - JOUR TI - Tracking the long-distance dispersal of marine organisms AU - Putman, Nathan F AU - He, Ruoying DA - 2013/// PY - 2013/// ER - TY - JOUR TI - The response of calcifying plankton to climate change in the Pliocene AU - Davis, C. V. AU - Badger, M. P. S. AU - Bown, P. R. AU - Schmidt, D. N. T2 - Biogeosciences AB - Abstract. As a result of anthropogenic pCO2 increases, future oceans are growing warmer and lower in pH and oxygen, conditions that are likely to impact planktic communities. Past intervals of elevated and changing pCO2 and temperatures can offer a glimpse into the response of marine calcifying plankton to changes in surface oceans under conditions similar to those projected for the future. Here we present new records of planktic foraminiferal and coccolith calcification (weight and size) from Deep Sea Drilling Project Site 607 (mid-North Atlantic) and Ocean Drilling Program Site 999 (Caribbean Sea) from the Pliocene, the last time that pCO2 was similar to today, and extending through a global cooling event into the intensification of Northern Hemisphere glaciation (3.3 to 2.6 million years ago). Test weights of both surface-dwelling Foraminifera Globigerina bulloides and thermocline-dwelling Foraminifera Globorotalia puncticulata vary with a potential link to regional temperature variation in the North Atlantic, whereas in the tropics Globigerinoides ruber test weight remains stable. In contrast, reticulofenestrid coccoliths show a narrowing size range and a decline in the largest lith diameters over this interval. Our results suggest no major changes in plankton calcite production during the high pCO2 Pliocene or during the transition into an icehouse world. DA - 2013/9/30/ PY - 2013/9/30/ DO - 10.5194/bg-10-6131-2013 VL - 10 IS - 9 SP - 6131-6139 J2 - Biogeosciences LA - en OP - SN - 1726-4189 UR - http://dx.doi.org/10.5194/bg-10-6131-2013 DB - Crossref ER - TY - RPRT TI - Legacy Sediments and Stream Water Quality: Estimating Volume, Nutrient Content, and Stream Bank Erosion in 303(d)-Impaired Waterways of the North Carolina Piedmont AU - Wegmann, K.W. AU - Osburn, C.L. AU - Lewis, R.Q. AU - Peszlen, I.M. AU - Mitasova, H. A3 - Water Resources Research Institute of the University of North Carolina DA - 2013/// PY - 2013/// M1 - 435 M3 - Report PB - Water Resources Research Institute of the University of North Carolina SN - 435 UR - https://repository.lib.ncsu.edu/bitstream/handle/1840.4/8190/NC-WRRI-435.pdf?sequence=1 ER - TY - JOUR TI - Correlation analysis between the channel current and luminosity of initial continuous and continuing current processes in an artificially triggered lightning flash AU - Zhou, Enwei AU - Lu, Weitao AU - Zhang, Yang AU - Zhu, Baoyou AU - Zheng, Dong AU - Zhang, Yijun T2 - Atmospheric Research AB - Using simultaneous high-speed camera records and channel-base current records in an artificially triggered negative lightning event, the correlation between the channel-base current and the integrated luminosity (IL) of the air-ionized part of the lightning channel is analyzed during the periods of the initial continuous current (ICC) process and eight continuing current (CC) processes. Depending on the current's changing trend (ascending or descending) and the luminosity property of the pixels used to calculate the IL from the high-speed camera records (including saturated pixels or not), the ICC and eight CC processes are divided into the saturated ascending stage (Stage-A), the saturated descending stage (Stage-B), the unsaturated ascending stage (Stage-C) and the unsaturated descending stage (Stage-D), including the descending tail stage (Stage-T, in which the channel-base current falls to zero). The analysis shows the following: (1) the IL is linearly correlated with the logarithmic value of the current in both Stage-A and Stage-B of two long CC processes, the ICC process and the CC process after the 7th return stroke, although the regression parameters (intercept and slope) in Stage-B are higher than those in Stage-A. This rule can also be found in most pulses of the long CC processes, where the IL in the descending stage is higher than that in the ascending stage at the same current value, regardless of which threshold index or height range used to calculate the IL are selected and regardless of whether the IL includes saturated pixels or not. (2) In the unsaturated stage of long CC processes, the channel current shows a significant linear correlation with the square root of the IL, and the fit of this relationship is much better than that in the saturated stage. Additionally, in each Stage-T of the eight CC processes following return strokes, the square root of the IL is significantly and linearly correlated with the current, and the regression slope is negatively correlated with the corresponding return stroke peak current. This result means that for the same channel current variation, the lower the return stroke peak current associated with the Stage-T of the CC process, the greater the luminosity variation. (3) For each of the above stages, the statistical model has a better fit when a higher threshold index, a more perpendicular channel or a greater height range is selected in the calculation of the IL. DA - 2013/7// PY - 2013/7// DO - 10.1016/j.atmosres.2012.10.020 VL - 129-130 SP - 79-89 J2 - Atmospheric Research LA - en OP - SN - 0169-8095 UR - http://dx.doi.org/10.1016/j.atmosres.2012.10.020 DB - Crossref KW - Triggered lightning KW - Channel-base current KW - Channel luminosity KW - High-speed photography KW - Linear regression ER - TY - JOUR TI - Characteristics of return stroke currents of classical and altitude triggered lightning in GCOELD in China AU - Zheng, Dong AU - Zhang, Yijun AU - Lu, Weitao AU - Zhang, Yang AU - Dong, Wansheng AU - Chen, Shaodong AU - Dan, Jianru T2 - Atmospheric Research AB - The currents of 29 return strokes (RSs) involved in 10 classical triggered lightning flashes (TLFs) and an altitude TLF conducted in Guangdong, China from 2008 to 2011 are analyzed for the first time. They have relatively greater peak values (geometric mean (GM) of 16.07 kA), average rate of rise between 10 and 90% (S10–90%, GM of 29.16 kA μs− 1), charge transfer within 1 ms (Q1 ms, GM of 1.36 C) and action integral within 1 ms (AI1 ms, GM of 5.39 × 103 A2 s), compared with those reported in other studies. The current peak value exhibits pronounced exponential relation with S10–90% (determination coefficient (R2) = 0.43) and maximum rate of rise (R2 = 0.77), power relation with Q1 ms (R2 = 0.89), and logarithmic relation with AI1 ms (R2 = 0.93). Additionally, the discharges associated with the processes of initial-stage return strokes (ISRSs) involved in two altitude TLFs, with the peak currents of 10.09 kA and 9.03 kA, respectively, are investigated. Their peak, 10–90% risetime, average rate of rise between 10 and 90% and maximum rate of rise are comparable to those of the RSs. The chopped-shape pulses closely following the ISRSs and the pulses associated with the disintegration and reconnections of the wire's channel are also discussed. DA - 2013/7// PY - 2013/7// DO - 10.1016/j.atmosres.2012.11.009 VL - 129-130 SP - 67-78 J2 - Atmospheric Research LA - en OP - SN - 0169-8095 UR - http://dx.doi.org/10.1016/j.atmosres.2012.11.009 DB - Crossref KW - Classical triggered lightning KW - Altitude triggered lightning KW - Return stroke KW - Current ER - TY - JOUR TI - Analysis and comparison of initial breakdown pulses for positive cloud-to-ground flashes observed in Beijing and Guangzhou AU - Zhang, Yang AU - Zhang, YiJun AU - Lu, WeiTao AU - Zheng, Dong T2 - Atmospheric Research AB - In order to further understand the initiating mechanism of positive cloud-to-ground flashes, the characteristics of initial breakdown pulse trains are investigated and compared by using the data of electric field observed in Beijing and Guangzhou. According to the difference in initial polarity between initial breakdown pulse and the first return stoke, three types of initial breakdown pulse trains, including the same polarity (type I), the opposite polarity (type II) and the composite polarity (type III), have been identified. The categories of initial breakdown pulse trains in Beijing are the same as those in Guangzhou. However, in Beijing and Guangzhou, the percentages of the types are obviously different, which may be caused by different charge configuration. In Beijing, the percentages of type I, type II and type III are 55%, 39% and 6%, respectively. In Guangzhou, the percentages of type I, type II and type III are 81%, 15% and 4%, respectively. By comparsion of the pulse train parameters, it can be found that the width of individual pulse and the interval of adjacent pulses are larger in Guangzhou than those in Beijing. The difference may be caused by different discharge distance. At the same time, both in Beijing and Guangzhou, the value of pulse train duration and the ratio of the maximum peak amplitude of initial breakdown pulse train to the amplitude of first return stroke peak for type II are smaller than those for type I. However, the value of the interval between initial breakdown pulse train and first return sroke for type II is larger than that for type I. We also find that, for type II, the ratio of the maximum peak amplitude of initial breakdown pulse train to the amplitude of first return stroke peak is obviously larger in Beijing than that in Guangzhou. We believe that the intensity of initiation breakdown process as type II is larger in the region with higher latitude. It can be speculated that the intensity of initial breakdown pulse train preceding positive first return stroke is further affected by the strength of lower positive charge region. Some possible causes of the differences have been discussed. DA - 2013/7// PY - 2013/7// DO - 10.1016/J.ATMOSRES.2013.03.006 VL - 129-130 SP - 34-41 J2 - Atmospheric Research LA - en OP - SN - 0169-8095 UR - http://dx.doi.org/10.1016/J.ATMOSRES.2013.03.006 DB - Crossref KW - Initial breakdown pulse KW - Positive cloud-to-ground flashes KW - Comparison KW - Beijing KW - Guangzhou ER - TY - JOUR TI - Impact of synoptic weather patterns on spatio-temporal variation in surface O3 levels in Hong Kong during 1999–2011 AU - Zhang, Yang AU - Mao, Huiting AU - Ding, Aijun AU - Zhou, Derong AU - Fu, Congbin T2 - Atmospheric Environment AB - Potential impacts of circulation patterns on surface ozone (O3) concentrations over Hong Kong were investigated for the time period of 1999–2011. Synoptic weathers during the study period were classified into seven typical patterns using a semi-objective weather typing technique. Temporal and spatial variations of O3 and total oxidant (Ox = O3 + NO2) in Hong Kong were found to be closely connected with weather/circulation patterns. The highest O3 concentrations (25 ppbv in average) among the 7 categories were found to be associated with the influence of Northwest Pacific typhoons, whereas the lowest average concentrations (13 pbbv) were linked to southerly flow introduced by summer monsoons. Ozone episodes with hourly mixing ratios exceeding 120 ppbv were found to be caused primarily by regional transport under influence of the tropical cyclone and by photochemical reactions upon prevalence of anti-cyclonic circulation. Taking into account interannual variabilities in frequency and intensity of circulation patterns, a reconstructed time series of O3 captured up to 50% of the observed interannual variability and 36% of the increasing trend. The study highlights an important linkage between weather/climate and air quality. DA - 2013/7// PY - 2013/7// DO - 10.1016/J.ATMOSENV.2013.02.047 VL - 73 SP - 41-50 J2 - Atmospheric Environment LA - en OP - SN - 1352-2310 UR - http://dx.doi.org/10.1016/J.ATMOSENV.2013.02.047 DB - Crossref KW - Synoptic weather KW - Photochemical pollution KW - Weather typing KW - Interannual variability KW - Long-term trend ER - TY - JOUR TI - Heterogeneous reaction of particle-associated triphenylene with NO3 radicals AU - Zhang, Yang AU - Shu, Jinian AU - Liu, Changgeng AU - Zhang, Yuanxun AU - Yang, Bo AU - Gan, Jie T2 - Atmospheric Environment AB - Although heterogeneous reactions of polycyclic aromatic hydrocarbons (PAHs) with atmospheric oxidants may be important loss processes for PAHs, our understanding of their kinetics and products is incomplete. The study of heterogeneous reaction of suspended triphenylene particles with NO3 radicals is undertaken in a flow-tube-reactor. The time-of-flight mass spectra of particulate triphenylene and its nitration products are obtained with vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer. 1- and 2-nitrotriphenylene are identified by GC–MS analysis of the products formed from the reaction of NO3 radicals with triphenylene coated on the inner bottom surface of a conical flask. 1-Nitrotriphenylene is formed in larger yield than 2-nitrotriphenylene. This phenomenon is different from what had been observed in previous studies of the gas-phase triphenylene nitration, showing that 2-nitrotriphenylene is the major nitration product. The experimental results may reveal the discrepancies between heterogeneous and homogeneous nitrations of triphenylene. DA - 2013/4// PY - 2013/4// DO - 10.1016/j.atmosenv.2012.11.052 VL - 68 SP - 114-119 J2 - Atmospheric Environment LA - en OP - SN - 1352-2310 UR - http://dx.doi.org/10.1016/j.atmosenv.2012.11.052 DB - Crossref KW - Triphenylene KW - NO3 radical KW - Heterogeneous reaction KW - Aerosol mass spectrometer ER - TY - CONF TI - Attributing Rise in Global Average Temperature to Emissions Traceable to Major Industrial Carbon Producer AU - Mera, Roberto J. AU - Allen, M.R. AU - Dalton, M. AU - Ekwurzel, B. AU - Frumhoff, P.C. AU - Heede, R. T2 - American Geophysical Union (AGU) Fall Meeting C2 - 2013/// CY - San Francisco, California DA - 2013/// PY - 2013/12// ER - TY - CONF TI - NCSU COAWST nowcast/forecast modeling system: implementation and examples AU - He, R. AU - Zambon, J.B. AU - Yao, Z. AU - Nelson, J. AU - Warner, J.C. T2 - Mid-Atlantic Regional Association Coastal Ocean Observing System (MARACOOS) Modeling Meeting C2 - 2013/// CY - Washington, DC DA - 2013/// PY - 2013/// ER - TY - CHAP TI - Climate Vulnerabilities of the Swine Industry AU - Rudek, J. AU - Aneja, V.P. T2 - Climate Vulnerability: Understanding and Addressing Threats to Essential Resources AB - When considering how swine production will be affected by climate, perhaps the best place to start is to consider the present day vulnerabilities of the industry. The swine industry, like most of the meat production industry, is based on intensive production with trends suggesting future increases in intensification. This industry model depends on cheap grain, cheap energy, and manageable disease control. Some expect that future temperature, and precipitation frequency and intensity may have direct impacts on nonintensive swine production but are not likely to directly affect intensive production because the barn environment is controlled. However, there could be an increase in the frequency, intensity, and severity of both severe storms (e.g., hurricanes, tornadoes, etc.), which might increase the upset of large open-air lagoon treatment systems and flooding of barns. This could lead to increased pressure on intensive operations to modify current manure treatment systems. Climate effects could, thus, have negative impacts on feed grain production, which will affect its availability and price. Climate influences would also have indirect impacts on energy costs as demands for renewable energy increase, which could also put upward pressure on feed grain prices as bioenergy production competes for feed grains. The climate impacts on growth, reproductive success, and distribution of diseases may impact the ability to manage disease. This concern may be heightened in intensive production relative to nonintensive systems owing to the density of animals. Future greenhouse gas mitigation efforts may produce costs or revenue opportunities for the swine industry. Last, the role of reactive nitrogen (Nr) in climate and other intertwined issues could be very important. Swine producers will need to adapt to all these changes to maintain production levels. PY - 2013/// DO - 10.1016/B978-0-12-384703-4.00217-3 VL - 2 SP - 77-87 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84902218558&partnerID=MN8TOARS ER - TY - RPRT TI - Fish Host Identification, Culture, and Propagation of the Tar Spinymussel and Yellow Lance: Two Rare Endemic Mussels of the North Carolina Piedmont AU - Levine, J.F. AU - Eads, C. DA - 2013/// PY - 2013/// ER - TY - CONF TI - Metabolic evidence of use of Bacillus subtilis as a food source in Elliptio complanata AU - Levine, JF AU - Nelson, S AU - Law, M AU - Showers, W AU - Stoskopf, M AU - Hurley-Sanders, J T2 - Freshwater Mollusk Conservation Society Symposium C2 - 2013/3// CY - Guntersville, Alabama DA - 2013/3// PY - 2013/3// ER - TY - CONF TI - Use of probiotics for In Vitro propagated freshwater mussels AU - Fox, T. AU - Levine, J.F. T2 - Freshwater Mollusk Conservation Society Symposium C2 - 2013/3// CY - Guntersville, Alabama DA - 2013/3// PY - 2013/3// ER - TY - CONF TI - Evaluating floating cages in ponds as potential low-input, high yield method for culturing freshwater mussels AU - Eads, C.B. AU - Levine, J.F. T2 - Freshwater Mollusk Conservation Society Symposium C2 - 2013/3// CY - Guntersville, Alabama DA - 2013/3// PY - 2013/3// ER - TY - JOUR TI - Subaqueous deltaic formation of the Old Yellow River (AD 1128–1855) on the western South Yellow Sea AU - Liu, Jian AU - Kong, Xianghuai AU - Saito, Yoshiki AU - Liu, J. Paul AU - Yang, Zuosheng AU - Wen, Chun T2 - Marine Geology AB - The Yellow River presently flows into the Bohai Sea, but during the period AD 1128–1855, the river (called the Old Yellow River, OYR) flowed into the western South Yellow Sea (SYS), where the dispersal of its sediment load was controlled by the interactions among alongshore currents, waves and tides, and shelf morphology. In this study, high-resolution shallow seismic profiles, vibrocores, boreholes, and water depth data, which were obtained during geological surveys in the western SYS in recent years, are used to examine the depositional pattern and stratigraphic record related to the OYR entering the sea. Our data reveal compound clinoform morphologies (double clinoforms) – a subaerial/subaqueous delta couplet – sourced by the OYR in the western SYS. The subaerial delta comprises the currently onshore delta plain and deltafront extending to ~ 17 m in water depth, while the subaqueous delta is composed of a wide, gently inclined topset and a relatively narrow, steeply sloping foreset, stretching seaward about 160-km away from the shoreline and showing a morphological asymmetry with a generally southward deflection relative to the OYR mouth. The topset is 25–100-km wide in a shore-normal direction at water depths of 10–25 m, but is generally less than 4-m thick. The foreset is much narrower and thicker than the topset, is generally 5–30-km wide at 10–45 m water depth and is mostly 4–16-m thick with a maximum thickness of 20 m; it shows seaward-dipping internal reflectors (generally 0.3–0.5°). The rollover points (topset–foreset transition) of the subaqueous clinoform range mostly between 10 and 25 m water depth. Results of 210Pb and 137Cs geochronology indicate that maximum sediment accumulation rates (1.06 to 2.16 cm/yr) correspond to the foreset region, with much lower rates in the topset and surrounding shallow-sea regions (< 0.64 cm/yr). Marine erosion due to abandonment of the delta after 1855 and artificial dike building around the abandoned delta coast since the 1930s have impacted the sediment accumulation in the delta front in the subaerial delta and subaqueous delta. Estimates of sediment budget suggest that about 34–52% of the total load primarily from the OYR (> 97%) in AD 1128–1855 has accumulated on the subaerial delta, and that about 10–16% of the total load on the subaqueous delta. Our data also reveal that the subaqueous delta related to the OYR is underlain by a large-scale clinoform (broadly confined to ~ 2.5–9.8 cal kyr BP in age) as thick as 4–13 m with seaward-dipping lower angled (< 0.3°) internal reflectors in comparison to those in the overlying foreset deposits. Energetic marine hydrodynamics (waves, tides, and alongshore coastal-currents) and sufficient sediment supply from the OYR are interpreted to be responsible for the across-shelf subaqueous delta morphology. DA - 2013/10// PY - 2013/10// DO - 10.1016/J.MARGEO.2013.07.003 VL - 344 SP - 19-33 J2 - Marine Geology LA - en OP - SN - 0025-3227 UR - http://dx.doi.org/10.1016/J.MARGEO.2013.07.003 DB - Crossref KW - Old Yellow River (1128-1855 period) KW - South Yellow Sea KW - subaqueous delta KW - clinoform ER - TY - JOUR TI - Short- and long-term conditioning of a temperate marine diatom community to acidification and warming AU - Tatters, Avery O. AU - Roleda, Michael Y. AU - Schnetzer, Astrid AU - Fu, Feixue AU - Hurd, Catriona L. AU - Boyd, Philip W. AU - Caron, David A. AU - Lie, Alle A. Y. AU - Hoffmann, Linn J. AU - Hutchins, David A. T2 - Philosophical Transactions of the Royal Society B: Biological Sciences AB - Ocean acidification and greenhouse warming will interactively influence competitive success of key phytoplankton groups such as diatoms, but how long-term responses to global change will affect community structure is unknown. We incubated a mixed natural diatom community from coastal New Zealand waters in a short-term (two-week) incubation experiment using a factorial matrix of warming and/or elevated p CO 2 and measured effects on community structure. We then isolated the dominant diatoms in clonal cultures and conditioned them for 1 year under the same temperature and p CO 2 conditions from which they were isolated, in order to allow for extended selection or acclimation by these abiotic environmental change factors in the absence of interspecific interactions. These conditioned isolates were then recombined into ‘artificial’ communities modelled after the original natural assemblage and allowed to compete under conditions identical to those in the short-term natural community experiment. In general, the resulting structure of both the unconditioned natural community and conditioned ‘artificial’ community experiments was similar, despite differences such as the loss of two species in the latter. p CO 2 and temperature had both individual and interactive effects on community structure, but temperature was more influential, as warming significantly reduced species richness. In this case, our short-term manipulative experiment with a mixed natural assemblage spanning weeks served as a reasonable proxy to predict the effects of global change forcing on diatom community structure after the component species were conditioned in isolation over an extended timescale. Future studies will be required to assess whether or not this is also the case for other types of algal communities from other marine regimes. DA - 2013/10/5/ PY - 2013/10/5/ DO - 10.1098/rstb.2012.0437 VL - 368 IS - 1627 SP - 20120437 UR - http://dx.doi.org/10.1098/rstb.2012.0437 KW - ocean acidification KW - warming KW - diatom KW - phytoplankton community KW - competition KW - adaptation ER - TY - JOUR TI - A Stable Isotope Tracer (δ13C) Study of Escherichia coli Retention in Two Freshwater Bivalves (Corbicula fluminea and Elliptio complanata) (Corbiculidae and Unionidae) AU - Bucci, J. P. AU - Szempruch, A. J. AU - Levine, J. F. T2 - American Malacological Bulletin AB - Bacteria are ingested by suspension feeding bivalves and can be an important component of their diet. This study evaluated whether a common bacterium of vertebrate enteric origin, Escherichia coli (Migula, 1895), is retained in the stomach or gill by two different freshwater bivalve species, Corbicula fluminea (Müller, 1974) and Elliptio complanata (Lightfoot, 1786). A series of diet treatment experiments were conducted comparing each anatomical section using a δ13C label and E. coli cells grown from stock cultures. A significant difference in δ13C values was related to anatomic structure among all treatment groups during a 7-day feeding experiment (24 jars, df = 140; F = 4.88; P < 0.001). A key finding was that in gill tissue, a significant difference was observed among <δ13C-labeled and unlabeled treatment combinations for both C. fluminea and E. complanata (F = 13.57; df = 31; P < 0.0001). The results suggest that water column E. coli are likely retained on gill tissue and to a lesser degree in the stomach in both E. complanata and C. fluminea. This study serves to validate the hypothesis that E. coli may be initially more abundant in gill tissue during sorting processes before being transferred to the stomach. DA - 2013/8// PY - 2013/8// DO - 10.4003/006.031.0207 VL - 31 IS - 2 SP - 281–288 SN - 0740-2783 2162-2698 UR - http://dx.doi.org/10.4003/006.031.0207 ER - TY - JOUR TI - Vertical Migration and Reproductive Patterns of a Long-Term Brooding Freshwater Mussel, Villosa constricta (Bivalvia: Unionidae) in a Small Piedmont Stream AU - Eads, Chris B. AU - Levine, Jay F. T2 - Freshwater Mollusk Biology and Conservation AB - We delineated a permanent 15 m by 9 m reach of a mussel bed in a small piedmont stream in the Cape Fear River Basin of North Carolina, USA. A total of 14 surveys were conducted at the study site from May 2005 to September 2006 at time intervals ranging from 2 weeks to 3 months. The study area was divided into fifteen 1-m-wide transects, and each transect was thoroughly searched twice during each survey event for any mussels on the substrate surface. We recorded species identification, length, gravidity (for known females) and replaced the mussel in the exact spot it was found. A pilot study was conducted to determine detection success with one, two, and three passes per transect and detection success was monitored on all transects throughout the study. We estimate that two passes over these transects yielded approximately 90% of the mussels on the sediment surface. Vertical migration patterns of Villosa constricta, and in particular females, were highly seasonal. Additional within-season variation could not be explained by seasonal patterns alone. Larger individuals were recaptured more frequently. Female mussels became gravid from August through March indicating that spawning and glochidial release took place over an extended period. In 2005, glochidial release was 1-2 months later than in 2006 and lasted through June. In 2006, glochidial release began before 7 February in 2006 and lasted through April. Smaller V. constricta (23-28 mm) were more likely to be gravid, and about half of the individual females were observed to spawn in consecutive years. DA - 2013/3/1/ PY - 2013/3/1/ DO - 10.31931/fmbc.v16i1.2013.29-40 VL - 16 IS - 1 SP - 29 J2 - Freshwater Mollusk Biology and Conservation OP - SN - 2472-2944 UR - http://dx.doi.org/10.31931/fmbc.v16i1.2013.29-40 DB - Crossref ER - TY - JOUR TI - Submicrometre particle filtration with a dc activated plasma textile AU - Rasipuram, S C AU - Wu, M AU - Kuznetsov, I A AU - Kuznetsov, A V AU - Levine, J F AU - Jasper, W J AU - Saveliev, A V T2 - Journal of Physics D: Applied Physics AB - Plasma textiles are novel fabrics incorporating the advantages of cold plasma and low-cost non-woven or woven textile fabrics. In plasma textiles, electrodes are integrated into the fabric, and a corona discharge is activated within and on the surface of the fabric by applying high voltages above 10 kV between the electrodes. When the plasma textile is activated, submicrometre particles approaching the textile are charged by the deposition of ions and electrons produced by the corona, and then collected by the textile material. A stable plasma discharge was experimentally verified on the surface of the textile that was locally smooth but not rigid. A filtration efficiency close to 100% was observed in experiments conducted on salt particles with diameters ranging from 50 to 300 nm. Unlike conventional fibrous filters, the plasma textile provided uniform filtration in this range, without exhibiting a maximum particle penetration size. DA - 2013/12/12/ PY - 2013/12/12/ DO - 10.1088/0022-3727/47/2/025201 VL - 47 IS - 2 SP - 025201 J2 - J. Phys. D: Appl. Phys. OP - SN - 0022-3727 1361-6463 UR - http://dx.doi.org/10.1088/0022-3727/47/2/025201 DB - Crossref KW - non-thermal plasmas KW - filtration KW - corona discharge KW - plasma textile ER - TY - JOUR TI - ASI:Dunaliellamarine microalgae to drop-in replacement liquid transportation fuel AU - Wang, Wei-Cheng AU - Allen, Elle AU - Campos, Andrew A. AU - Cade, Rushyannah Killens AU - Dean, Lisa AU - Dvora, Mia AU - Immer, Jeremy G. AU - Mixson, Stephanie AU - Srirangan, Soundarya AU - Sauer, Marie-Laure AU - Schreck, Steven AU - Sun, Keyi AU - Thapaliya, Nirajan AU - Wilson, Cameron AU - Burkholder, JoAnn AU - Grunden, Amy M. AU - Lamb, H. Henry AU - Sederoff, Heike AU - Stikeleather, Larry F. AU - Roberts, William L. T2 - Environmental Progress & Sustainable Energy AB - Microalgae are a promising biofuels feedstock, theoretically yielding concentrations of triacylglycerides (TAGs) per unit area that are far higher than traditional feedstocks due to their rapid growth. Dunaliella is particularly advantageous as a feedstock because it is currently commercially mass cultured, thrives in salt water, and has no cell wall. Fourteen strains of Dunaliella have been investigated for growth rates and lipid production in mass culture and tested for enhanced lipid production under a range of environmental stressors including salinity, pH, nitrogen and phosphorus limitation, and light regime. The nuclear genome has been sequenced for four of these strains, with the objective of increasing carbon flux through genetic engineering. Electroflocculation followed by osmotic membrane rupturing may be a very energy and cost efficient means of harvesting the lipid bodies from Dunaliella. A technically feasible and scalable thermo-catalytic process to convert the lipids into replacements for liquid transportation fuels has been developed. The lipids were converted into long-chain alkanes through continuous thermal hydrolysis followed by fed-batch thermo-catalytic decarboxylation. These alkanes can be reformed into renewable diesel via conventional catalytic hydrocarbon isomerization reactions to improve cold flow properties, if desired. © 2013 American Institute of Chemical Engineers Environ Prog, 32: 916–925, 2013 DA - 2013/9/11/ PY - 2013/9/11/ DO - 10.1002/EP.11855 VL - 32 IS - 4 SP - 916-925 J2 - Environ. Prog. Sustainable Energy LA - en OP - SN - 1944-7442 UR - http://dx.doi.org/10.1002/EP.11855 DB - Crossref ER - TY - JOUR TI - Recognition of Pleistocene marine terraces in the southwest of Portugal (Iberian Peninsula): Evidences of regional quaternary uplift AU - Figueiredo, P.M. AU - Cabral, J. AU - Rockwell, T.K. T2 - Annals of Geophysics AB - <p>Southwest mainland Portugal is located close to the Eurasia-Nubia plate boundary and is characterized by moderate seismicity, although strong events have occurred as in 1755 (Mw≥8), 1969, (Mw 7.9), and more recently in 2007 (Mw 5.9) and 2009 (Mw 5.5), all located in the offshore. No historical earthquakes with onshore rupture are known for this region. At the coastline, high sea cliffs, incised drainages, emergent marine abrasion platforms and paleo sea cliffs indicate that this region is undergoing uplift, although no morphological features were found that could be unequivocally associated with the 1755 mega earthquake. To better understand the recent tectonic activity in this sector of Iberia, it is necessary not only to analyze active structures on land, but also to search for evidence for deformation that may relate to inferred offshore active structures. We thus conducted a study of marine terraces along the coastline to identify regional vertical crustal motions. Several poorly preserved surfaces with thin sedimentary deposits, comprising old beach sediments, were recognized at elevations starting at 2 m elevation and rising inland up to a regional abrasion platform situated at about 120 m a.s.l.. We identified distinct paleo sea level references at several locations at consistent elevations. This terrace sequence is likely Late Pleistocene in age, with individual platforms correlative to MIS 5 high stands and is coherent with a long-term slow uplift of the littoral zone for the southwest of Portugal. Although dating of discrete platforms is an ongoing and difficult task, preliminary correlations of paleo-shoreline elevations suggest that the uplift rate is in the range of 0.1-0.2 mm/yr.</p> DA - 2013/// PY - 2013/// DO - 10.4401/ag-6276 VL - 56 IS - 6 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899946479&partnerID=MN8TOARS ER - TY - JOUR TI - The 1909 Benavente (Portugal) earthquake: Search for the source AU - Cabral, J. AU - Moniz, C. AU - Batlló, J. AU - Figueiredo, P. AU - Carvalho, J. AU - Matias, L. AU - Teves-Costa, P. AU - Dias, R. AU - Simão, N. T2 - Natural Hazards AB - The Lower Tagus River Valley has been affected by severe earthquakes comprising distant events, as in 1755, and local earthquakes, as in 1344, 1531, and 1909. The 1909 earthquake was located NE of Lisbon, near Benavente, causing serious damage and many losses. Mw 6.0 has been assessed for this earthquake and a reverse faulting focal mechanism solution has been calculated. Poor epicenter location, possible directivity and site effects, low fault slip rates, and the thick Cenozoic sedimentary cover make difficult correlation with regional structures. The focal mechanism indicates an ENE reverse fault as source, though it does not match any outcropping active structure suggesting that the event could have been produced by a blind thrust beneath the Cenozoic sedimentary fill. Hidden sources, inferred from seismic reflection data, are a possible NE structure linking the Vila Franca de Xira and the Azambuja faults, or the southern extension of the later. Evidence of surface rupturing is inhibited by the thick Holocene alluvial cover and the high fluvial sedimentation rate, though a slightly depressed area was identified in the Tagus alluvial plain W of Benavente which was investigated as possible geomorphic evidence of co-seismic surface deformation. A high-resolution seismic reflection profile was acquired across a 0.5 m high scarp at this site, and two trenches were opened across the scarp for paleoseismic research. Some deformation of dubious tectonic origin was found, requiring further studies. DA - 2013/// PY - 2013/// DO - 10.1007/s11069-011-0062-8 VL - 69 IS - 2 SP - 1211-1227 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84885021803&partnerID=MN8TOARS KW - Benavente earthquake KW - Seismotectonics KW - Lower Tagus Valley KW - Portugal ER - TY - JOUR TI - Study reveals what controls contribution of total suspended solids from legacy sediments in Piedmont streams AU - Wegmann, K. T2 - Water Resources Research Institute News of the University of North Carolina DA - 2013/// PY - 2013/// IS - 382 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84878803040&partnerID=MN8TOARS ER - TY - JOUR TI - Miocene rejuvenation of topographic relief in the southern Appalachians AU - Gallen, S.F. AU - Wegmann, K.W. AU - Bohnenstiehl, D.W.R. T2 - GSA Today DA - 2013/// PY - 2013/// DO - 10.1130/GSATG163A.1 VL - 23 IS - 2 SP - 4-10 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84874675049&partnerID=MN8TOARS ER - TY - JOUR TI - Improving mass-wasting inventories by incorporating debris flow topographic signatures AU - Lyons, N.J. AU - Mitasova, Helena AU - Wegmann, Karl T2 - Landslides DA - 2013/// PY - 2013/// DO - 10.1007/s10346-013-0398-0 VL - 11 IS - 3 SP - 1-13 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84875894016&partnerID=MN8TOARS ER - TY - JOUR TI - Representational bias in phytoliths from modern soils of central North America: Implications for paleovegetation reconstructions AU - Hyland, Ethan AU - Smith, Selena Y. AU - Sheldon, Nathan D. T2 - Palaeogeography, Palaeoclimatology, Palaeoecology AB - Understanding localized patterns and community compositions of vegetation in an environment is critical to the reconstruction of climatic and ecological conditions across all spatiotemporal scales. One of the most accurate and useful ways to characterize vegetation, and therefore to describe the climatic and ecological conditions of a location, is through the plant fossil record. Phytoliths (plant silica microfossils) are often preserved in the absence of other paleobotanical data and are becoming more widely used for deep-time vegetation reconstructions. Significant work has been done to standardize the analytical methodology of phytolith extraction, statistical analysis, and interpretation, but more detailed investigations are needed to understand how well a given soil assemblage represents the actual aboveground plant biomass for a given ecosystem. We present results from paired soil phytolith assemblages and local vegetation assemblages across the central United States, including temperate forest, grassland, and rangeland/scrubland ecosystems. Phytolith assemblages obtained via extractions from soil A-horizons were compared to percent cover of species and plant biomass estimates obtained via in situ field observations and aerial estimates of tree cover to analyze differences in the relative abundance of forest/woody vegetation vs. grasses. Soil phytolith assemblages from all sites average a 29% bias toward the grass morphotypes as compared to actual aboveground biomass observations, and comparisons to percent cover yielded broadly comparable bias figures. Percent bias estimates do not show significant correlations to most environmental factors (temperature, precipitation, local elevation), however, an extremely strong correlation (p < 0.001) was observed with soil order type. This is likely due to the fact that soil order reflects both vegetation type and chemical factors known to affect overall phytolith assemblages; therefore, soil order is a proxy that aggregates several sources of bias. As a result, we suggest further research into the development of correction factors between phytolith sample assemblages and their interpreted past counterpart ecosystems based on estimates derived from modern analyses of each major soil order type. Such background corrections are essential to the continued use of phytoliths as a proxy for past vegetation and ecological reconstructions of temperate ecosystems throughout the Phanerozoic record. DA - 2013/3// PY - 2013/3// DO - 10.1016/J.PALAEO.2013.01.026 VL - 374 SP - 338-348 J2 - Palaeogeography, Palaeoclimatology, Palaeoecology LA - en OP - SN - 0031-0182 UR - http://dx.doi.org/10.1016/J.PALAEO.2013.01.026 DB - Crossref KW - Paleosol KW - Phytolith KW - Taphonomy KW - Soil KW - Vegetation ER - TY - JOUR TI - Coupled CO2-climate response during the Early Eocene Climatic Optimum AU - Hyland, Ethan G. AU - Sheldon, Nathan D. T2 - Palaeogeography, Palaeoclimatology, Palaeoecology AB - The Early Eocene Climatic Optimum (EECO) has been characterized as a prolonged warm event indicated by increased atmospheric pCO2, temperatures, precipitation, and biological turnover. A new paleoenvironmental reconstruction using integrated pedological, geochemical, and isotopic data from the Green River Basin (Green River/Great Divide region) provides a high-resolution record of environmental and climatic change throughout the EECO. Our reconstruction indicates that this region, and likely much of the margin of paleolake Gosiute, was a stable, fluvially-controlled floodplain environment with evidence of large scale continuous soil development and features comparable with modern Alfisols (temperate forest soils). Regional climate data from multiple proxies indicates that the period was warm-temperate and semi-arid to sub-humid, with a peak interval from about 51.5–50.9 Ma that exhibits significantly warmer (~ 7 °C) and wetter (~ 750 mm yr− 1) conditions, resulting in major changes to the local weathering regime. Isotopic analyses also indicate a rapid increase to high atmospheric pCO2 values (~ 1700 ppmV) and a shift in the δ13C composition of pedogenic carbonates during this peak interval that appear to define and provide a cause for this significant regional response to global climatic change. The new data, when combined with foraminiferal δ13C records, are consistent with CO2 ventilation from a deep marine reservoir source. This multi-proxy reconstruction suggests that the EECO may have had a superimposed “peak” of climatic and ecological change on land. DA - 2013/1// PY - 2013/1// DO - 10.1016/j.palaeo.2012.10.011 VL - 369 SP - 125-135 J2 - Palaeogeography, Palaeoclimatology, Palaeoecology LA - en OP - SN - 0031-0182 UR - http://dx.doi.org/10.1016/j.palaeo.2012.10.011 DB - Crossref KW - Paleosols KW - Paleoclimate KW - Early Eocene Climatic Optimum KW - Carbon dioxide KW - Green River Basin ER - TY - JOUR TI - The origin of graben and ridges in Rachmaninoff, Raditladi, and Mozart basins, Mercury AU - Blair, David M. AU - Freed, Andrew M. AU - Byrne, Paul K. AU - Klimczak, Christian AU - Prockter, Louise M. AU - Ernst, Carolyn M. AU - Solomon, Sean C. AU - Melosh, H. Jay AU - Zuber, Maria T. T2 - Journal of Geophysical Research: Planets AB - The Rachmaninoff, Raditladi, and Mozart peak‐ring impact basins on Mercury display a distinctive pattern of tectonic features consisting of a central zone that is either devoid of tectonic landforms or contains small ridges, a medial annulus of prominent and predominantly circumferentially oriented graben, and a distal zone displaying graben that occur in a mix of orientations and that are less evident toward the peak ring. Here we use finite element models to explore three candidate scenarios for the formation of these tectonic features: (1) thermal contraction of the interior smooth plains, (2) isostatic uplift of the basin floor, and (3) subsidence following volcanic loading. Our results suggest that only thermal contraction can account for the observed pattern of graben, whereas some combination of subsidence and global contraction is the most likely explanation for the central ridges in Rachmaninoff and Mozart. Thermal contraction models, however, predict the formation of graben in the centermost region of each basin, where no graben are observed. We hypothesize that graben in this region were buried by a thin, late‐stage flow of plains material, and images of partially filled graben provide evidence of such late‐stage plains emplacement. These results suggest that the smooth plains units in these three basins are volcanic in origin. The thermal contraction models also imply a cooling unit ~1 km thick near the basin center, further supporting the view that plains‐forming lavas on Mercury were often of sufficiently high volume and low viscosity to pool to substantial thicknesses within basins and craters. DA - 2013/1// PY - 2013/1// DO - 10.1029/2012JE004198 VL - 118 IS - 1 SP - 47-58 J2 - J. Geophys. Res. Planets LA - en OP - SN - 2169-9097 UR - http://dx.doi.org/10.1029/2012JE004198 DB - Crossref ER - TY - JOUR TI - Investigating the origin of candidate lava channels on Mercury with MESSENGER data: Theory and observations AU - Hurwitz, Debra M. AU - Head, James W. AU - Byrne, Paul K. AU - Xiao, Zhiyong AU - Solomon, Sean C. AU - Zuber, Maria T. AU - Smith, David E. AU - Neumann, Gregory A. T2 - Journal of Geophysical Research: Planets AB - Abstract Volcanic plains identified on Mercury are morphologically similar to lunar mare plains but lack constructional and erosional features that are prevalent on other terrestrial planetary bodies. We analyzed images acquired by the MESSENGER spacecraft to identify features on Mercury that may have formed by lava erosion. We used analytical models to estimate eruption flux, erosion rate, and eruption duration to characterize the formation of candidate erosional features, and we compared results with analyses of similar features observed on Earth, the Moon, and Mars. Results suggest that lava erupting at high effusion rates similar to those required to form the Teepee Butte Member of the Columbia River flood basalts (0.1–1.2 × 10 6 m 3 s –1 ) would have been necessary to form wide valleys (>15 km wide) observed in Mercury's northern hemisphere, first by mechanical erosion to remove an upper regolith layer, then by thermal erosion once a lower rigid layer was encountered. Alternatively, results suggest that lava erupting at lower effusion rates similar to those predicted to have formed Rima Prinz on the Moon (4400 m 3 s –1 ) would have been required to form, via thermal erosion, narrower channels (<7 km wide) observed on Mercury. Although these results indicate how erosion might have occurred on Mercury, the observed features may have formed by other processes, including lava flooding terrain sculpted during the formation of the Caloris basin in the case of the wide valleys, or impact melt carving channels into impact ejecta in the case of the narrower channels. DA - 2013/3// PY - 2013/3// DO - 10.1029/2012JE004103 VL - 118 IS - 3 SP - 471-486 J2 - J. Geophys. Res. Planets LA - en OP - SN - 2169-9097 UR - http://dx.doi.org/10.1029/2012JE004103 DB - Crossref KW - thermal erosion KW - mechanical erosion KW - sinuous rilles KW - effusive volcanism ER - TY - JOUR TI - Insights into the subsurface structure of the Caloris basin, Mercury, from assessments of mechanical layering and changes in long-wavelength topography AU - Klimczak, Christian AU - Ernst, Carolyn M. AU - Byrne, Paul K. AU - Solomon, Sean C. AU - Watters, Thomas R. AU - Murchie, Scott L. AU - Preusker, Frank AU - Balcerski, Jeffrey A. T2 - Journal of Geophysical Research: Planets AB - The volcanic plains that fill the Caloris basin, the largest recognized impact basin on Mercury, are deformed by many graben and wrinkle ridges, among which the multitude of radial graben of Pantheon Fossae allow us to resolve variations in the depth extent of associated faulting. Displacement profiles and displacement‐to‐length scaling both indicate that faults near the basin center are confined to a ~ 4‐km‐thick mechanical layer, whereas faults far from the center penetrate more deeply. The fault scaling also indicates that the graben formed in mechanically strong material, which we identify with dry basalt‐like plains. These plains were also affected by changes in long‐wavelength topography, including undulations with wavelengths of up to 1300 km and amplitudes of 2.5 to 3 km. Geographic correlation of the depth extent of faulting with topographic variations allows a first‐order interpretation of the subsurface structure and mechanical stratigraphy in the basin. Further, crosscutting and superposition relationships among plains, faults, craters, and topography indicate that development of long‐wavelength topographic variations followed plains emplacement, faulting, and much of the cratering within the Caloris basin. As several examples of these topographic undulations are also found outside the basin, our results on the scale, structural style, and relative timing of the topographic changes have regional applicability and may be the surface expression of global‐scale interior processes on Mercury. DA - 2013/10// PY - 2013/10// DO - 10.1002/JGRE.20157 VL - 118 IS - 10 SP - 2030-2044 J2 - J. Geophys. Res. Planets LA - en OP - SN - 2169-9097 UR - http://dx.doi.org/10.1002/JGRE.20157 DB - Crossref KW - Caloris basin KW - Mercury KW - Graben KW - Topographic undulations KW - Fault scaling KW - Mechanical stratigraphy ER - TY - JOUR TI - Dark spots on Mercury: A distinctive low-reflectance material and its relation to hollows AU - Xiao, Zhiyong AU - Strom, Robert G. AU - Blewett, David T. AU - Byrne, Paul K. AU - Solomon, Sean C. AU - Murchie, Scott L. AU - Sprague, Ann L. AU - Domingue, Deborah L. AU - Helbert, Jörn T2 - Journal of Geophysical Research: Planets AB - Abstract Orbital images acquired by the MErcury, Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft reveal a distinctive low‐reflectance material on the surface of Mercury. Such material occurs in small, isolated, and thin surficial units. We term these features “dark spots.” Dark spots have the lowest average reflectance yet documented on the planet. In every case observed at sufficiently high resolution, dark spots feature hollows at their centers. Not all hollows, however, are surrounded by a dark spot. Dark spots have been found on low‐reflectance smooth plains, intercrater plains, heavily cratered terrain, and impact craters at almost all longitudes on Mercury, but they have not been documented on high‐reflectance smooth plains material. Dark spots are one of the youngest endogenic features on Mercury, and some postdate craters with distinctive rays. Sulfides may be the phase responsible for the low albedo of dark spot material. We propose that dark spots form during the initial stages of hollow formation, perhaps in a manner similar to intense outgassing events that feature exit velocities in excess of 100 m/s. Such outgassing could contemporaneously produce a depression that constitutes an embryonic hollow. Under this scenario, dark spot material is subsequently removed or modified by regolith gardening or other surface processes on time scales shorter than the lifetime of the central hollow. DA - 2013/9// PY - 2013/9// DO - 10.1002/JGRE.20115 VL - 118 IS - 9 SP - 1752-1765 J2 - J. Geophys. Res. Planets LA - en OP - SN - 2169-9097 UR - http://dx.doi.org/10.1002/JGRE.20115 DB - Crossref KW - Mercury KW - dark spots KW - volatiles ER - TY - JOUR TI - The distribution and origin of smooth plains on Mercury AU - Denevi, Brett W. AU - Ernst, Carolyn M. AU - Meyer, Heather M. AU - Robinson, Mark S. AU - Murchie, Scott L. AU - Whitten, Jennifer L. AU - Head, James W. AU - Watters, Thomas R. AU - Solomon, Sean C. AU - Ostrach, Lillian R. AU - Chapman, Clark R. AU - Byrne, Paul K. AU - Klimczak, Christian AU - Peplowski, Patrick N. T2 - Journal of Geophysical Research: Planets AB - Orbital images from the MESSENGER spacecraft show that ~27% of Mercury's surface is covered by smooth plains, the majority (>65%) of which are interpreted to be volcanic in origin. Most smooth plains share the spectral characteristics of Mercury's northern smooth plains, suggesting they also share their magnesian alkali‐basalt‐like composition. A smaller fraction of smooth plains interpreted to be volcanic in nature have a lower reflectance and shallower spectral slope, suggesting more ultramafic compositions, an inference that implies high temperatures and high degrees of partial melting in magma source regions persisted through most of the duration of smooth plains formation. The knobby and hummocky plains surrounding the Caloris basin, known as Odin‐type plains, occupy an additional 2% of Mercury's surface. The morphology of these plains and their color and stratigraphic relationships suggest that they formed as Caloris ejecta, although such an origin is in conflict with a straightforward interpretation of crater size–frequency distributions. If some fraction is volcanic, this added area would substantially increase the abundance of relatively young effusive deposits inferred to have more mafic compositions. Smooth plains are widespread on Mercury, but they are more heavily concentrated in the north and in the hemisphere surrounding Caloris. No simple relationship between plains distribution and crustal thickness or radioactive element distribution is observed. A likely volcanic origin for some older terrain on Mercury suggests that the uneven distribution of smooth plains may indicate differences in the emplacement age of large‐scale volcanic deposits rather than differences in crustal formational process. DA - 2013/5// PY - 2013/5// DO - 10.1002/JGRE.20075 VL - 118 IS - 5 SP - 891-907 J2 - J. Geophys. Res. Planets LA - en OP - SN - 2169-9097 UR - http://dx.doi.org/10.1002/JGRE.20075 DB - Crossref KW - Mercury KW - Volcanism KW - Smooth Plains ER - TY - JOUR TI - An assemblage of lava flow features on Mercury AU - Byrne, Paul K. AU - Klimczak, Christian AU - Williams, David A. AU - Hurwitz, Debra M. AU - Solomon, Sean C. AU - Head, James W. AU - Preusker, Frank AU - Oberst, Jürgen T2 - Journal of Geophysical Research: Planets AB - Abstract In contrast to other terrestrial planets, Mercury does not possess a great variety of volcanic features, its history of volcanism instead largely manifest by expansive smooth plains. However, a set of landforms at high northern latitudes on Mercury resembles surface flow features documented on Earth, the Moon, Mars, and Venus. The most striking of such landforms are broad channels that host streamlined islands and that cut through the surrounding intercrater plains. Together with narrower, more sinuous channels, coalesced depressions, evidence for local flooding of intercrater plains by lavas, and a first‐order analysis of lava flow rates, the broad channels define an assemblage of flow features formed by the overland flow of, and erosion by, voluminous, high‐temperature, low‐viscosity lavas. This interpretation is consistent with compositional data suggesting that substantial portions of Mercury's crust are composed of magnesian, iron‐poor lithologies. Moreover, the proximity of this partially flooded assemblage to extensive volcanic plains raises the possibility that the formation of these flow features may preface total inundation of an area by lavas emplaced in a flood mode and that they escaped complete burial only due to a waning magmatic supply. Finally, that these broad channels on Mercury are volcanic in nature yet resemble outflow channels on Mars, which are commonly attributed to catastrophic water floods, implies that aqueous activity is not a prerequisite for the formation of such distinctive landforms on any planetary body. DA - 2013/6// PY - 2013/6// DO - 10.1002/JGRE.20052 VL - 118 IS - 6 SP - 1303-1322 J2 - J. Geophys. Res. Planets LA - en OP - SN - 2169-9097 UR - http://dx.doi.org/10.1002/JGRE.20052 DB - Crossref KW - lava erosion KW - lava flows KW - outflow channels KW - Mercury KW - MESSENGER KW - volcanism ER - TY - CONF TI - The importance of organic aerosol to CCN concentrations and characteristics at a forested site in Colorado AU - Levin, E. J. T. AU - Prenni, A. J. AU - Palm, B. AU - Day, D. AU - Campuzano-Jost, P. AU - Petters, M. D. AU - Kreidenweis, S. M. AU - DeMott, P. J. AU - Jimenez, J. AU - Smith, J. N. T2 - NUCLEATION AND ATMOSPHERIC AEROSOLS: 19th International Conference AB - We measured size-resolved CCN concentrations over an annual cycle and during a summer intensive study at a remote, forested location in Colorado. From these data we derived aerosol hygroscopicity and size-resolved two-component composition. During the summer intensive, aerosol composition was also measured with an aerosol mass spectrometer, and we use these data to confirm hygroscopicity-derived composition. Throughout the study and at all measured sizes, aerosol composition was predominately organic with resulting low hygroscopicity, κave = 0.16 ± 0.08. New particle formation appeared to be an important source of aerosol number and the newly nucleated particles were inferred to be predominately organic. C2 - 2013/// C3 - DA - 2013/// DO - 10.1063/1.4803401 PB - AIP UR - http://dx.doi.org/10.1063/1.4803401 DB - Crossref KW - Aerosol KW - CCN KW - Kappa KW - New particle formation ER - TY - JOUR TI - Geomorphology of the Anthropocene: Understanding the surficial legacy of past and present human activities AU - Jefferson, Anne J. AU - Wegmann, Karl W. AU - Chin, Anne T2 - Anthropocene DA - 2013/10// PY - 2013/10// DO - 10.1016/J.ANCENE.2013.10.005 VL - 2 SP - 1-3 J2 - Anthropocene LA - en OP - SN - 2213-3054 UR - http://dx.doi.org/10.1016/J.ANCENE.2013.10.005 DB - Crossref ER - TY - JOUR TI - A graph-based approach to find teleconnections in climate data AU - Kawale, Jaya AU - Liess, Stefan AU - Kumar, Arjun AU - Steinbach, Michael AU - Snyder, Peter AU - Kumar, Vipin AU - Ganguly, Auroop R. AU - Samatova, Nagiza F. AU - Semazzi, Fredrick T2 - Statistical Analysis and Data Mining AB - Pressure dipoles are important long distance climate phenomena (teleconnection) characterized by pressure anomalies of the opposite polarity appearing at two different locations at the same time. Such dipoles have been proven important for understanding and explaining the variability in climate in many regions of the world, e.g. the El Niño Southern Oscillation (ENSO) climate phenomenon, which is described by opposite pressure anomalies between the west and east Pacific and is known to be responsible for precipitation and temperature anomalies worldwide. This paper presents a graph-based approach called shared reciprocal nearest neighbor approach that considers only reciprocal positive and negative edges in the shared nearest neighbor graph to find the dipoles. One crucial aspect of our approach to the analysis of such networks is a careful treatment of negative correlations, whose proper consideration is critical for finding the dipoles. Further, our work shows the importance of modeling the time-dependent patterns of the dipoles in a changing climate in order to better capture the impact of important climate phenomena on the globe. To show the utility of finding dipoles using our approach, we show that the data driven dynamic climate indices generated from our algorithm generally perform better than static indices formed from the fixed locations used by climate scientists in terms of capturing impact on global temperature and precipitation. Our approach can generate a single snapshot picture of all the dipole interconnections on the globe in a given dataset and thus makes it possible to study the changes in dipole interactions and movements. As teleconnections are crucial in the understanding of the global climate system, there is a pressing need to better understand the behavior and interactions of these atmospheric processes as well as to capture them precisely. Our systematic graph-based approach to find the teleconnections in climate data is an attempt in that direction. © 2012 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 6: 158–179, 2013 DA - 2013/4/17/ PY - 2013/4/17/ DO - 10.1002/SAM.11181 VL - 6 IS - 3 SP - 158-179 J2 - Statistical Analy Data Mining LA - en OP - SN - 1932-1864 UR - http://dx.doi.org/10.1002/SAM.11181 DB - Crossref KW - graph algorithm KW - teleconnections KW - dipole discovery ER - TY - JOUR TI - Changes in weather and climate extremes: State of knowledge relevant to air and water quality in the United States AU - Peterson, Thomas C. AU - Karl, Thomas R. AU - Kossin, James P. AU - Kunkel, Kenneth E. AU - Lawrimore, Jay H. AU - McMahon, James R. AU - Vose, Russell S. AU - Yin, Xungang T2 - Journal of the Air & Waste Management Association AB - Air and water quality are impacted by extreme weather and climate events on time scales ranging from minutes to many months. This review paper discusses the state of knowledge of how and why extreme events are changing and are projected to change in the future. These events include heat waves, cold waves, floods, droughts, hurricanes, strong extratropical cyclones such as nor'easters, heavy rain, and major snowfalls. Some of these events, such as heat waves, are projected to increase, while others, with cold waves being a good example, will decrease in intensity in our warming world. Each extreme's impact on air or water quality can be complex and can even vary over the course of the event. DA - 2013/10/11/ PY - 2013/10/11/ DO - 10.1080/10962247.2013.851044 VL - 64 IS - 2 SP - 184-197 J2 - Journal of the Air & Waste Management Association LA - en OP - SN - 1096-2247 2162-2906 UR - http://dx.doi.org/10.1080/10962247.2013.851044 DB - Crossref ER - TY - JOUR TI - Production mechanisms, number concentration, size distribution, chemical composition, and optical properties of sea spray aerosols AU - Meskhidze, Nicholas AU - Petters, Markus D. AU - Tsigaridis, Kostas AU - Bates, Tim AU - O'Dowd, Colin AU - Reid, Jeff AU - Lewis, Ernie R. AU - Gantt, Brett AU - Anguelova, Magdalena D. AU - Bhave, Prakash V. AU - Bird, James AU - Callaghan, Adrian H. AU - Ceburnis, Darius AU - Chang, Rachel AU - Clarke, Antony AU - de Leeuw, Gerrit AU - Deane, Grant AU - DeMott, Paul J. AU - Elliot, Scott AU - Facchini, Maria Cristina AU - Fairall, Chris W. AU - Hawkins, Lelia AU - Hu, Yongxiang AU - Hudson, James G. AU - Johnson, Matthew S. AU - Kaku, Kathleen C. AU - Keene, William C. AU - Kieber, David J. AU - Long, Michael S. AU - Mårtensson, Monica AU - Modini, Rob L. AU - Osburn, Chris L. AU - Prather, Kimberly A. AU - Pszenny, Alex AU - Rinaldi, Matteo AU - Russell, Lynn M. AU - Salter, Matthew AU - Sayer, Andrew M. AU - Smirnov, Alexander AU - Suda, Sarah R. AU - Toth, Travis D. AU - Worsnop, Douglas R. AU - Wozniak, Andrew AU - Zorn, Sören R. T2 - Atmospheric Science Letters AB - The impact of sea spray aerosols on global climate remains one of the most uncertain components of the aerosol–radiation–climate problem, but has received less attention than the impacts of terrestrial and anthropogenic aerosols. The last decade has produced a large body of information regarding the sources and composition of marine aerosols, resulting in a reassessment of the complex role that sea spray particles play in climate and various geophysical phenomena. As sea spray aerosol contributes substantially to the preindustrial, natural background which provides the baseline on top of which anthropogenic forcing should be quantified, and because the ocean covers over 70% of the Earth's surface, the representation of sea spray aerosol in climate models strongly influences the predicted impact on climate of anthropogenic aerosols via direct and indirect effects. In addition, climate change affects atmospheric parameters, such as wind speed which has controlling effect on the production of sea spray aerosol. Recent reviews on sea spray aerosol production and composition (de Leeuw et al., 2011) summarized the state of the art and remaining uncertainties. Over forty scientists from six countries convened in Raleigh, NC on June 4–6 2012 to review the status and prospects of sea spray aerosol research. Participants were researchers from the oceanography and atmospheric science communities, including academia, private industry, and government agencies. The workshop was held with the primary objectives of (1) identifying the most critical open questions regarding sea spray aerosol and developing a list of priorities for conducting and facilitating novel research and (2) ranking the most pressing science questions based on their feasibility impact on reducing the current uncertainty ranges for different processes. The four main focus groups followed by the three breakout sessions determined the most urgent questions that would improve quantification of sea spray aerosol-radiation-climate interactions, with special emphasis on the production flux, number concentrations, chemical composition, nucleation properties, and optical properties. Instead of relying on individual presentations, the meeting format was structured to emphasize consensus-building among participants who collectively discussed successes, weaknesses, and research goals and methods of achieving them in their specific expertise of sea spray aerosol research. Following a keynote presentation by Gerrit de Leeuw highlighting open questions from his perspective, the workshop participants were divided into four focus groups (Figure 1): in situ field measurements, laboratory experiments, remote sensing, and regional and global modeling. Following short presentations by the group leaders in which successes and difficulties of past measurements/modeling/remote sensing efforts were reviewed and important missing parameters were identified, participants deliberated in breakout sessions to discuss three major topics: sea spray source function, atmospheric aging and budget, and optical properties. In each session, participants elaborated on the current sea spray aerosol-related research status and identified future priorities. In the following we reiterate the main discussion points summarized in each of the four main sessions. The discussion in this session focused on methods to measure fundamental quantities of interest for determining the impact of sea spray aerosols on climate, specifically, size-resolved number concentrations and production fluxes with information on size-resolved chemical composition. Various participants described the need for measurements of additional parameters to better understand the sources and sinks of sea spray aerosol. Key among these were background meteorology, biogeochemistry and physics of the ocean mixed layer including surface roughness/wind stress, wave breaking and bubble plume dynamics, and whitecap fraction (defined as the fraction of the ocean surface covered by whitecaps generated by breaking waves). Much of the discussion was centered on the difficulties quantifying the sources of sea spray aerosol, especially the relationship between the ocean surface whitecap fraction and aerosol production. The difficulties of obtaining accurate measurements of sea spray aerosol production flux were also discussed. The group consensus was that the whitecap fraction measurements need to be improved through standardization of measurement protocols, better linked with bubble plume spectra, and performed alongside of direct field measurements of sea spray aerosol production (such as by eddy covariance) over a range of wind speeds. Organic matter in sea spray aerosols was also noted as an important topic, mainly in the context of the need for a better understanding of the processes that control its amount in sea spray aerosol, whether it is internally or externally mixed with inorganic components, its atmospheric evolution and interaction with secondary species, and the current lack of a good proxy for organic enrichment of marine aerosols. Correlations of chlorophyll-a (Chl-a) and dissolved organic carbon (DOC) concentrations at the sea surface, the most commonly used proxies, with organic fraction of sea spray aerosol are not conclusive and need to be further examined. In terms of sea spray aerosol removal processes, participants described the difficulty of measuring net aerosol fluxes near the ocean surface. Overall, session participants agreed that interdisciplinary field campaigns evaluating marine aerosol production and processing would benefit from coordinated measurements of ocean conditions (e.g. whitecap fraction, bubble spectra, surface ocean wave properties, upper ocean ecology and chemistry, photic-zone optical properties) and routine atmospheric measurements [e.g. aerosol number and mass size distribution, size-resolved aerosol chemistry, aerosol hygroscopicity, cloud condensation nuclei (CCN) spectra, ice nuclei (IN) spectra, aerosol optical properties and optical depth, relative humidity, surface wind speed, cloud fraction, and precipitation rates]. Because entrainment of air and aerosol from the free troposphere to the marine boundary layer (MBL) modifies marine aerosol concentrations within the MBL, assessment of entrainment should also be incorporated. Additionally, measurements of trace components such as black carbon concentrations can indicate the extent to which the pristine MBL aerosol composition may have been perturbed by anthropogenic sources. Discussion of future major integrated field studies considering the highly nonlinear and nonuniform pattern of sea spray emissions that arises through the combined effect of physical, chemical, and biological parameters emphasized the importance of site selection. Ideal criteria would include (1) minimal continental influence on the marine aerosol (lack of pollution, dust, etc.), (2) stable meteorology and well-defined boundary layer, (3) predictable gradients and seasonality in wind speed, whitecaps, and biological productivity over significant spatial scales that are statistically resolvable by satellite, and (4) favorable logistics for water, airborne, remote sensing, and possibly land measurements taken on a long-term basis. Such locations were identified as the channel between Maui and the Big Island of Hawaii in the equatorial trade wind region, where a natural wind tunnel in the MBL is formed from mountains reaching into the free troposphere which focuses and accelerates clean marine-air-mass winds and the Mace Head in the N E Atlantic, perhaps one of the most utilized and best characterized stations possessing very strong sea-salt signals in periods of low biological activity and the strongest organic-enriched sea spray signals during periods of high biological activity. These and other locations (e.g. Amsterdam Island in the Southern Indian Ocean) representing different climate zones, biological productivities, and degrees of anthropogenic influence should be targeted for coordinated studies of marine aerosol production and evolution. Characterizing seasonal and spatial variation will be essential to improve the input that field campaigns can provide toward validating large-scale models. This session concentrated on the role of canonical experiments in understanding sea spray emissions. Discussion focused on the representativeness of results of experiments both in the laboratory and in the field, terminology, standardization of seawater, and the need for intercomparison studies. The representativeness of laboratory experimentation was discussed in the context of the scale of physical models (e.g. depth of model ocean and bubble path length) and methods of bubble generation (e.g. frits, jets, falling water, single bubble vs multiple bubbles and associated surface rafts-transient features of all breaking waves that are sustained by bubble plume detrainment). It was suggested that laboratory measurements could help identify a ‘universal’ parameter (e.g. bubble volume flux) that can be used for scaling laboratory experiments to model global production of sea spray. Despite the various challenges that hamper such a development, there was a clear consensus that canonical studies leading to improved mechanistic understanding of the emission process are necessary. The terminology discussion concerned ambiguities and confusion that arise from imprecise definitions and lack of clear distinctions; for instance, DOC versus particulate organic carbon (POC), a raft of bubbles versus foam, and dry foam versus wet foam. Terminology uncertainties are largely due to the interdisciplinary nature of sea spray aerosol research, with oceanographers and atmospheric scientists frequently using different nomenclature. While avoiding strict definitions of these terms here, the consensus was that investigators should clearly define all quantities and that the field should conscientiously strive toward convergence on terminology. Some participants expressed the need to develop some standardization of seawater used in bubble bursting experiments so that the effects of different bubble generation systems could be better understood. In addition, it was suggested that there is a need for an intercomparison workshop, possibly similar in structure and design to the recent ice nucleation workshops held at the Aerosols Interaction and Dynamics in the Atmosphere (AIDA) cloud chamber facility in Germany (DeMott et al., 2011). The intercomparison may lead to the development of a ‘pod’ of the most essential instruments to be deployable in field campaigns or in the laboratory and may provide insight into how different bubble generation mechanisms (e.g. weirs vs frits) can affect sea spray production fluxes. This session began with an overview of the contribution of remote sensing to understanding sea spray aerosol, ranging from ground-based systems including the Maritime Aerosol Network (MAN) (Smirnov et al., 2009) a ship-borne data acquisition initiative complementing island-based AEROsol RObotic NETwork (AERONET) measurements to satellites missions such as the MODerate resolution Imaging Spectroradiometer (MODIS), Multi-angle Imaging Spectral Radiometer (MISR), Advanced Along Track Scanning Radiometer (AATSR), POLarization and Directionality of the Earth's Reflectances (PARASOL), MEdium-spectral Resolution Imaging Spectrometer (MERIS), Sea-viewing Wide Field-of-view Sensor (SeaWiFS), and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO). Ground, satellite, and aircraft-based remote sensing can provide quantities that are or may be useful in estimating sea spray aerosol emissions and budget, including aerosol optical depth (AOD), surface wind speed, wave parameters, Chl-a concentration, colored dissolved organic matter (CDOM) concentration, whitecap fraction, and sea surface temperature (SST). Session participants suggested that there is a need for more aircraft data to improve spatial and spectral resolution (e.g. accurate high vertical-resolution aerosol profiles near the ocean surface). It was also suggested that ground- and ship-based systems for measurement of marine aerosol properties should be expanded. Quantities such as aerosol chemical speciation, sea state (roughness and whitecap fraction), and AOD (near clouds and under high-wind conditions) could be determined through improvements in the horizontal, vertical, temporal, and spectral resolution of in situ measurements. An open question is the extent to which sea spray aerosols (or even marine organics aerosols) can be distinguished from continental aerosols via remote sensing techniques. If such a distinction can be achieved, it will greatly enhance the ability of remote sensing to evaluate marine aerosol production, processing, and radiative effects. Discussion by session participants identified and evaluated successes and limitations of sea spray aerosol modeling. Successes included the implementation of interactive sea-salt aerosol emissions into most models (including treatment of the sea spray aerosol organic fraction in some) and the preliminary quantification of changes in CCN spectra associated with the various sea spray aerosol source functions. One of the main difficulties in modeling sea spray aerosol production is the lack of flux and concentration observations, particularly long-term size-resolved aerosol number concentration and chemical composition. Currently, available data compilations are coarsely resolved and include only mass concentrations. The need for a compilation of size-resolved marine aerosol number concentration database, similar to the University of Miami ocean aerosol network dataset was stressed. (This dataset is established by D. L. Savoie and J. M. Prospero and hosted by the Goddard Institute of Space Physics as part of the Global Aerosol Climatoloy Project; Mishchenko et al., 2002). It was pointed out by the participants that many size-resolved observations of number concentration exist, but there has not been a dedicated effort to compile them into an integrated database. Having long-term data with seasonal and spatial variability is essential for input to/validation of large-scale chemical transport and climate models. Many of the participants discussed the uncertainties in the organic enrichment of sea spray aerosol and issues with the use of satellite-derived surface Chl-a concentrations and other oceanic proxies like DOC, POC, or CDOM. More fundamentally, there was a debate about whether the current method of parameterizing sea spray aerosol emissions by using wind speed at 10-m reference height needs to be extended or replaced by incorporating other more directly related quantities, including sea state, wind stress, etc. Development of improved parameterizations is hampered by the lack of information on the production mechanism of sea spray organics, and highlights the need for a more integrated research approach that strengthens the linkages between modeling, laboratory, and field experiments. The group also discussed the feasibility of using the same source functions for the inorganic and organic components of sea spray aerosols, as well as issues that are related with the mixing state of these two components and their impact on the model-simulated climate, primarily via aerosol removal and CCN activity. The key question that remains unanswered is how the aerosol production schemes should be modified in the models to consider organic component of sea spray. Some suggestions for future work included (1) a model intercomparison study similar to the AeroCom studies (e.g. Koch et al., 2011), (2) development of size- and composition-resolved source functions for marine aerosols, (3) development of an adjoint model that estimates the sensitivity of model output (e.g. surface concentration) with respect to model inputs (e.g. emissions), and (4) compilation of a global marine aerosol size distribution and chemical composition dataset. In addition to summarizing the current state of the science and outlining future needs and methods for reducing the uncertainties in the field, the workshop participants also created a prioritization matrix of a number of sea spray aerosol research areas from three broad categories: the source function, optical properties, and the MBL budget. For each topic, the current level of understanding, the impact full understanding would have in the field if achieved, and the potential resources needed, including the difficulty of performing the task, were ranked on a scale ranging from one to five. Individual responses were collected, and ‘low’, ‘medium’, and ‘high’ level of understanding was assigned based on the consensus achieved by majority of workshop participants. These rankings are summarized in Table 1. The order of listing of topics does not convey any indication of priority settings by the attendees. The group identified seven topics that have the lowest understanding and the highest impact if achieved: (1) size-resolved chemical composition/ hygroscopicity, (2) mixing state, (3) wet removal, (4) photochemical aging, (5) cloud processing, (6) seawater/microlayer chemical composition, and (7) size-resolved organic speciation. Nearly all of these topics are related to the organic fraction/distinct organic species of sea spray aerosol and characterized by the difficulty in measurement techniques and/or the problem of attribution of the measured properties to sea spray emission, either in the laboratory or the field. Although size-resolved number flux (i.e. production) was not included in this list, we stress that as long as it remains unknown, chemical composition and aging remain inconsequential. As a result, the impact achieved by understanding the size-resolved number flux is high. Within the source function category, topics pertaining to the size-resolved properties were mostly classified as having a lower level of understanding and higher impact if achieved than the bulk aerosol properties. Topics such as mixing state and the ability of sea spray to serve as ice nuclei were ranked at low level of understanding. It is encouraging to note that no topics in the optical properties section were ranked to have low understanding. The highest impact if achieved was assigned to the topic of humidified scattering. Several topics in the MBL budget category were evaluated at a medium or high impact if achieved because of their importance in determining surface concentrations and lifetime, yet generally had low levels of understanding because relatively little research has been undertaken on them compared with that on the sea spray aerosol source function. Seven topics were identified as high difficulty and/or high cost, and five of these were also ranked as low understanding and high impact if achieved: (1) size-resolved chemical composition/hygroscopicity, (2) size-resolved organic speciation, (3) mixing state, (4) photochemical aging, and (5) cloud processing. Broadly, the first three and the last two are two areas where concerted efforts such as large-scale field campaigns and joint laboratory studies could lead to more cost-effective ways to collectively address these topics. Two other topics, seawater/microlayer chemical composition and wet removal, were ranked as low scientific understanding, high impact if achieved, and medium difficulty, and thus are worth targeting in the near future. Ultimately, the participants of this meeting stressed the need for better communication between interdisciplinary fields of sea spray aerosol research. Collaboration between those doing laboratory studies, field measurements, remote sensing, and modeling efforts was stated as being essential in order to quickly improve the understanding of the complex issues involving sea spray aerosols. The workshop presentations are available online (http://www4.ncsu.edu/nmeskhi/Marine_Aerosol_Workshop/WEBSITE.html). Funding for this workshop was provided by the National Science Foundation—NSF (AGS-1236957), the Department of Energy office of Biological and Environmental Research (DOE-DE-SC0007995), the National Oceanic and Atmospheric Administration—NOAA (Z763701), the National Aeronautics and Space Administration—NASA (NNX12AK27G), and the Marine Meteorology and Atmospheric Effects Program at the Department of Defense Office of Naval Research (DOD-ONR). D. Ceburnis acknowledges EPA Ireland fellowship grant for travel support. K. Prather and G. Deane were supported by NSF (CHE-1038028) grant. A. H. Callaghan would like to acknowledge financial support from the Irish Research Council and Marie Curie actions under FP7 and the National Science Foundation Physical Oceanography Division (Grant OCE-1155123). DA - 2013/6/21/ PY - 2013/6/21/ DO - 10.1002/ASL2.441 VL - 14 IS - 4 SP - 207-213 J2 - Atmos. Sci. Lett. LA - en OP - SN - 1530-261X UR - http://dx.doi.org/10.1002/ASL2.441 DB - Crossref KW - sea spray aerosol KW - source function KW - chemical composition KW - number concentration KW - optical properties ER - TY - JOUR TI - LINKING OPTICAL AND CHEMICAL PROPERTIES OF DISSOLVED ORGANIC MATTER IN NATURAL WATERS AU - Osburn, Christopher L. AU - Stedmon, Colin A. AU - Spencer, Robert G. M. AU - Stubbins, Aron T2 - Limnology and Oceanography Bulletin AB - Limnology and Oceanography BulletinVolume 22, Issue 3 p. 78-82 ArticleFree Access LINKING OPTICAL AND CHEMICAL PROPERTIES OF DISSOLVED ORGANIC MATTER IN NATURAL WATERS Christopher L. Osburn, Christopher L. Osburn closburn@ncsu.edu Department of Marine, Earth, and Atmospheric Sciences, NC State University, Raleigh, North Carolina, USASearch for more papers by this authorColin A. Stedmon, Colin A. Stedmon National Institute for Aquatic Resources, Technical University of Denmark, Charlottenlund, DenmarkSearch for more papers by this authorRobert G. M. Spencer, Robert G. M. Spencer Woods Hole Research Center, Falmouth, Massachusetts, USASearch for more papers by this authorAron Stubbins, Aron Stubbins Skidaway Institute of Oceanography, Savannah, Georgia, USASearch for more papers by this author Christopher L. Osburn, Christopher L. Osburn closburn@ncsu.edu Department of Marine, Earth, and Atmospheric Sciences, NC State University, Raleigh, North Carolina, USASearch for more papers by this authorColin A. Stedmon, Colin A. Stedmon National Institute for Aquatic Resources, Technical University of Denmark, Charlottenlund, DenmarkSearch for more papers by this authorRobert G. M. Spencer, Robert G. M. Spencer Woods Hole Research Center, Falmouth, Massachusetts, USASearch for more papers by this authorAron Stubbins, Aron Stubbins Skidaway Institute of Oceanography, Savannah, Georgia, USASearch for more papers by this author First published: 18 December 2014 https://doi.org/10.1002/lob.201322378Citations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume22, Issue3August 2013Pages 78-82 RelatedInformation DA - 2013/8// PY - 2013/8// DO - 10.1002/lob.201322378 VL - 22 IS - 3 SP - 78-82 J2 - Limnology and Oceanography Bulletin LA - en OP - SN - 1539-607X UR - http://dx.doi.org/10.1002/lob.201322378 DB - Crossref ER - TY - JOUR TI - Science and Technology Centers Deliver New Oceanographic Concepts to Educators AU - Spence, L. AU - Thomas, C. T2 - Current: Journal of Marine Science Education DA - 2013/// PY - 2013/// VL - 28 SP - 2–4 UR - https://www.marine-ed.org/journal ER - TY - JOUR TI - Physiological and Biogeochemical Traits of Bleaching and Recovery in the Mounding Species of Coral Porites lobata: Implications for Resilience in Mounding Corals AU - Levas, Stephen J. AU - Grottoli, Andréa G. AU - Hughes, Adam AU - Osburn, Christopher L. AU - Matsui, Yohei T2 - PLoS ONE AB - Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s) that are responsible for mounding coral holobiont resilience to bleaching. Furthermore, the potential of dissolved organic carbon (DOC) as a source of fixed carbon to bleached corals has never been determined. Here, Porites lobata corals were experimentally bleached for 23 days and then allowed to recover for 0, 1, 5, and 11 months. At each recovery interval a suite of analyses were performed to assess their recovery (photosynthesis, respiration, chlorophyll a, energy reserves, tissue biomass, calcification, δ13C of the skeletal, δ13C, and δ15N of the animal host and endosymbiont fractions). Furthermore, at 0 months of recovery, the assimilation of photosynthetically acquired and zooplankton-feeding acquired carbon into the animal host, endosymbiont, skeleton, and coral-mediated DOC were measured via 13C-pulse-chase labeling. During the first month of recovery, energy reserves and tissue biomass in bleached corals were maintained despite reductions in chlorophyll a, photosynthesis, and the assimilation of photosynthetically fixed carbon. At the same time, P. lobata corals catabolized carbon acquired from zooplankton and seemed to take up DOC as a source of fixed carbon. All variables that were negatively affected by bleaching recovered within 5 to 11 months. Thus, bleaching resilience in the mounding coral P. lobata is driven by its ability to actively catabolize zooplankton-acquired carbon and seemingly utilize DOC as a significant fixed carbon source, facilitating the maintenance of energy reserves and tissue biomass. With the frequency and intensity of bleaching events expected to increase over the next century, coral diversity on future reefs may favor not only mounding morphologies but species like P. lobata, which have the ability to utilize heterotrophic sources of fixed carbon that minimize the impact of bleaching and promote fast recovery. DA - 2013/5/2/ PY - 2013/5/2/ DO - 10.1371/journal.pone.0063267 VL - 8 IS - 5 SP - e63267 ER - TY - JOUR TI - Simulating the impact of the large-scale circulation on the 2-m temperature and precipitation climatology T2 - Climate Dynamics DA - 2013/4// PY - 2013/4// DO - 10.1007/s00382-012-1440-y UR - http://dx.doi.org/10.1007/s00382-012-1440-y KW - Regional climate modeling KW - Interior grid nudging KW - Spectral nudging KW - Analysis nudging KW - Bermuda high ER - TY - JOUR TI - Open source geospatial education and research AU - Mitasova, H. AU - Schweik, C. T2 - GIM International DA - 2013/// PY - 2013/// VL - 27 IS - 8 SP - 25-28 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84885105445&partnerID=MN8TOARS ER - TY - JOUR TI - Managing dune landscape changes at Jockey's Ridge State Park, North Carolina AU - Mitas, O. AU - Mitasova, H. AU - Brothers, G. AU - Weaver, K. T2 - Tourism in Marine Environments AB - Coastal dunes are challenging to manage due to their dynamic nature, vulnerable ecosystems, and recreational demand. A limited management approach was studied at Jockey's Ridge, the largest active dune on the US Atlantic coast. Visitor experience data, digital elevation models, and informal stories and photos were integrated in a case study approach. Data revealed the value of an integrated management approach that preserved the dune as a unique “living” geomorphological feature with interventions limited to the park borders. The accessibility of the dune to visitors facilitated intense, enjoyable interactions with nature. Elevation data show that the management approach has maintained the dune's unique naturally dynamic character, revealing the benefits of preserving processes rather than features. DA - 2013/// PY - 2013/// DO - 10.3727/154427313X13818453739477 VL - 9 IS - 3-4 SP - 155-167 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84893504743&partnerID=MN8TOARS ER - TY - JOUR TI - Lines in the Sand: Geomorphic and Geospatial Characterization and Interpretation of Sandy Shorelines and Beaches AU - Paris, P. AU - Starek, M.J. AU - Hardin, E. AU - Kurum, O. AU - Overton, M. AU - Mitasova, H. T2 - Geography Compass AB - Abstract The world's beaches hold an appeal that draws millions of people to live and, each year, millions more to relax and play. However, in the face of this allure fly the strain and consequence of overuse. Increasingly, the imperative to find ways to effectively manage this fragile, finite resource compels science to learn more about this complex, multifaceted system. It is through such understanding that the best hope for effective management lies. In this paper, we look at ways in which researchers study the shore. Specifically, we'll examine this active corner of geomorphology as seen through the lens of the geoscientist, with particular focus on two geomorphic features: the shoreline and the beach. Further emphasis is placed on how investigators have historically, and until today, applied concepts, tools, and methods borrowed from the spatial sciences and, in more recent times, geographic information technologies to the study of the shoreline and the beach. We begin this exploration with a first principal: the definition of shoreline—the boundary where land and water meet. Next, we examine ways in which researchers over the years have worked to generate a suitable shoreline analog or proxy for study. We then follow with a look at how shoreline position is measured—an area where much recent research attention has been placed. Taking matters a step further, we explore the beach, and beach change in three dimensions, looking at how investigators are using geospatial technologies to characterize and analyze change. Finally, we look at various ways in which researchers predict shore and beach changes, by combining spatial analysis and technology with numerical and statistical models. © 2012 The Author. Geography Compass © 2013 Blackwell Publishing Ltd DA - 2013/// PY - 2013/// DO - 10.1111/gec3.12041 VL - 7 IS - 5 SP - 315-343 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84878461269&partnerID=MN8TOARS ER - TY - BOOK TI - GIS-Based Soil Erosion Modeling AU - Mitasova, H. AU - Barton, M. AU - Ullah, I. AU - Hofierka, J. AU - Harmon, R.S. AB - This chapter explains the theory and methods for GIS-based modeling of soil erosion, sediment transport, and deposition by surface water flow. The mathematical foundations of erosion models are introduced and simplified equations, suitable for GIS implementation, are derived. The presented methods cover modeling of hillslope erosion and deposition, gully formation, and landscape evolution processes. Coupling of erosion models with GIS is discussed, followed by examples of GIS implementation of simple and advanced models. The concepts and methods are illustrated using two case studies, that focus on feedbacks between the human activity and landscape processes. DA - 2013/// PY - 2013/// DO - 10.1016/B978-0-12-374739-6.00052-X VL - 3 SE - 228-258 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84903414788&partnerID=MN8TOARS ER - TY - JOUR TI - SUMMARY VISUALIZATIONS FOR COASTAL SPATIAL-TEMPORAL DYNAMICS AU - Thakur, Sidharth AU - Tateosian, Laura AU - Mitasova, Helena AU - Hardin, Eric AU - Overton, Margery T2 - INTERNATIONAL JOURNAL FOR UNCERTAINTY QUANTIFICATION AB - Digital scans of dynamic terrains such as coastal regions are now being gathered at high spatial and temporal resolution. Although standard tools based on geographic information systems (GIS) are indispensable for analyzing geospatial data, they have limited support to display time-dependent changes in data and information such as statistical distributions and uncertainty in data. We present a set of techniques for visually summarizing the dynamics of coastal dunes. We visualize summary statistics of important data attributes and risk or vulnerability indices as functions of both spatial and temporal dimensions in our data and represent uncertainty in the data set. We apply standard techniques, the space time cube and clustering, in novel ways to the domain of geomorphology. We combine surface-mapping and imagery with summary visualizations to retain important geographical context in the visualizations and reduce clutter due to direct plotting of statistical data in displays of geospatial information. We also address some issues pertaining to visualization of summary statistics for geographical regions at varying scales. We demonstrate visualization tools on time series of elevation models from the Outer Banks of North Carolina and observe temporal-spatial trends therein. DA - 2013/// PY - 2013/// DO - 10.1615/int.j.uncertaintyquantification.2012003969 VL - 3 IS - 3 SP - 241-253 SN - 2152-5099 KW - uncertainty KW - visualization KW - geovisualization KW - glyph-based visualization KW - spatial-temporal analysis KW - space-time cube KW - coastal terrain KW - geomorphology KW - GRASS GIS KW - Outer Banks ER - TY - JOUR TI - Coupled Heterogeneous Association Rule Mining (CHARM): Application toward Inference of Modulatory Climate Relationships AU - Gonzalez, Doel L., II AU - Pendse, Saurabh V. AU - Padmanabhan, Kanchana AU - Angus, Michael P. AU - Tetteh, Isaac K. AU - Srinivas, Shashank AU - Villanes, Andrea AU - Semazzi, Fredrick AU - Kumar, Vipin AU - Samatova, Nagiza F. T2 - 2013 IEEE 13TH INTERNATIONAL CONFERENCE ON DATA MINING (ICDM) AB - The complex dynamic climate system often exhibits hierarchical modularity of its organization and function. Scientists have spent decades trying to discover and understand the driving mechanisms behind western African Sahel summer rainfall variability, mostly via hypothesis-driven and/or first-principles based research. Their work has furthered theory regarding the connections between various climate patterns, but the key relationships are still not fully understood. We present Coupled Heterogeneous Association Rule Mining (CHARM), a computationally efficient methodology that mines higher-order relationships between these subsystems' anomalous temporal phases with respect to their effect on the system's response. We apply this to climate science data, aiming to infer putative pathways/cascades of modulating events and the modulating signs that collectively define the network of pathways for the rainfall anomaly in the Sahel. Experimental results are consistent with fundamental theories of phenomena in climate science, especially physical processes that best describe sub-regional climate. DA - 2013/// PY - 2013/// DO - 10.1109/icdm.2013.142 SP - 1055-1060 SN - 1550-4786 KW - association rules KW - climate KW - data coupling KW - discovery ER - TY - JOUR TI - Which MJO Events Affect North American Temperatures? AU - Schreck, Carl J., III AU - Cordeira, Jason M. AU - Margolin, David T2 - MONTHLY WEATHER REVIEW AB - Abstract Tropical convection from the Madden–Julian oscillation (MJO) excites and amplifies extratropical Rossby waves around the globe. This forcing is reflected in teleconnection patterns like the Pacific–North American (PNA) pattern, and it can ultimately result in temperature anomalies over North America. Previous studies have not explored whether the extratropical response might vary from one MJO event to another. This study proposes a new index, the multivariate PNA (MVP), to identify variations in the extratropical waveguide over the North Pacific and North America that might affect the response to the MJO. The MVP is the first combined EOF of 20–100-day OLR, 850-hPa streamfunction, and 200-hPa streamfunction over the North Pacific and North America. The North American temperature patterns that follow each phase of the MJO change with the sign of the MVP. For example, real-time multivariate MJO (RMM) phase 5 usually leads to warm anomalies over eastern North America. This relationship was only found when the MVP was negative, and it was not associated with El Niño or La Niña. RMM phase 8, on the other hand, usually leads to cold anomalies. Those anomalies only occur if the MVP is positive, which happens somewhat more frequently during La Niña years. Composite analyses based on combinations of the MJO and the MVP show that variability in the Pacific jet and its associated wave breaking play a key role in determining whether and how the MJO affects North American temperatures. DA - 2013/11// PY - 2013/11// DO - 10.1175/mwr-d-13-00118.1 VL - 141 IS - 11 SP - 3840-3850 SN - 1520-0493 KW - Madden-Julian oscillation KW - Pacific-North American pattern KW - oscillation KW - Statistical forecasting KW - Intraseasonal variability ER - TY - JOUR TI - Subaqueous deltaic formation of the Old Yellow River (AD 1128-1855) on the western South Yellow Sea AU - Liu, J. AU - Kong, X. H. AU - Saito, Y. AU - Liu, J. P. AU - Yang, Z. S. AU - Wen, C. T2 - Marine Geology DA - 2013/// PY - 2013/// VL - 344 SP - 19-33 ER - TY - JOUR TI - Rainfall effect on wind waves and the turbulence beneath air-sea interface AU - Dongliang, Zhao AU - Xin, Ma AU - Bin, Liu AU - Lian, Xie T2 - ACTA OCEANOLOGICA SINICA DA - 2013/11// PY - 2013/11// DO - 10.1007/s13131-013-0372-7 VL - 32 IS - 11 SP - 10-20 SN - 1869-1099 KW - rainfall KW - wind wave KW - wave age KW - turbulence KW - turbulent kinetic energy ER - TY - JOUR TI - Nest occurrence and survival of King Rails in fire-managed coastal marshes in North Carolina and Virginia AU - Rogers, Samantha L. AU - Collazo, Jaime A. AU - Drew, Christina A. T2 - JOURNAL OF FIELD ORNITHOLOGY AB - Prescribed burning maintains marsh habitat, but its impact on breeding King Rails (Rallus elegans) is poorly understood. This practice may serve as a means to enhance populations of a species whose numbers are declining in the southeastern United States. We used call-broadcast surveys and nest searches to categorize the state of occupied plots by the presence or non-presence of nesting activity in the Back Bay region, North Carolina and Virginia, in 2010. We also used nest video surveillance to estimate nest survival in 2009 and 2010. The probabilities that a surveyed plot was occupied (1) and contained an active nest (2) were higher in recently burned marsh plots (0–1 year-since-burn [YSB]) than in plots with ≥2 YSB at Mackay Island and Back Bay National Wildlife Refuges (NWRs). Highest probabilities were recorded in 0–1 YSB plots at Mackay Island NWR ( = 0.96 ± 0.04, = 0.75 ± 0.18), and the lowest in ≥2 YSB plots at Back Bay NWR ( = 0.21 ± 0.10, = 0.03 ± 0.04). Nest survival from egg laying to hatching (31 d) was 0.48 (95% confidence interval [CI] = 0.06–0.83), with an estimated 0.79 (95% CI = 0.29–0.96) survival rate for the incubation stage (21 d). These nest survival estimates for King Rails in fire-managed marshes were similar to estimates for other populations. Measures of vegetation cover, proxies for concealment, did not differ between nest sites and unused sites, even within recently burned marshes. This lack of differences in vegetation structure suggests that regrowth occurs rapidly during the period between burning (winter months) and the onset of reproduction (late April). Thus, recently burned marshes may benefit nesting King Rails by providing nest concealment. In addition, burned marshes may enhance availability of many invertebrates. Although we found that the probability that surveyed plots contained active nests was higher in recently burned marsh plots, estimates of fledging success are needed before marsh burns can be considered an effective means of fostering population growth. Ocurrencia de nidos y supervivencia del Rascón real en pantanos costeros con manejo de fuego en Carolina del Norte y Virginia Los incendios controlados ayudan a mantener los pantanos, pero su impacto en la reproducción del Rascón real (Rallus elegans) está poco estudiado. Esta práctica puede servir como un medio de incrementar poblaciones de una especie cuyos números han declinado en el sudeste de Estados Unidos. Usamos censos con playback y búsqueda de nidos a fin de categorizar el estado de ocupación de parcelas por la presencia o ausencia de actividad de nido en la región de Back Bay, en Carolina del Norte y Virginia, en 2010. Utilizamos también monitoreo por video de nidos para estimar la supervivencia de nido en 2009 y 2010. Las probabilidades de que una parcela censada se encontrara ocupado () y de que contuviese nidos activos () fueron más altos en pantanos recientemente incendiados (0–1 años desde quema [ADQ]) que en parcelas con ≥2 ADQ en Isla Mackay y en el Refugio Nacional de Vida Silvestre (RNVS) de Back Bay. Las probabilidades más altas fueron registradas en parcelas con 0–1 ADQ en Isla Mackay Island RNVS ( = 0.96 ± 0.04, = 0.75 ± 0.18), y la más baja en parcelas con ADQ ⩾2 en Back Bay RNVS ( = 0.21 ± 0.10, = 0.03 ± 0.04). La supervivencia de nido desde la puesto de huevos hasta la eclosión (31 días) fue de 0.48 (95% IC = 0.06–0.83), con un estimado de 0.79 (95% IC = 0.29–0.96) para la tasa de supervivencia para el estadio de incubación (21 días). Estos estimados para la supervivencia de nidos para el Rascón real en pantanos con manejo del fuego controlados fueron similares a los estimados para otras poblaciones. Las medidas de cubertura vegetal, representantes de camuflaje, no difirieron entre las parcelas con nidos y las parcelas sin nidos, aún dentro de pantanos recientemente quemados. Esta falta de diferencias en la estructura de la vegetación sugiere que el crecimiento de la vegetación ocurre rápidamente en el período entre la quema (meses de invierno) y el inicio de la temporada reproductiva (fines de Abril). Así, pantanos recientemente quemados podrían beneficiar a la nidada del Rascón real al proveer camuflaje para el nido. Adicionalmente, los pantanos quemados podrían aumentar la disponibilidad de muchos invertebrados. Aún cuando encontramos que la probabilidad de que las parcelas censadas contuviesen nidos activos era mayor en parcelas recientemente quemadas, estimaciones del éxito de los volantones son necesarias antes de que la quema en pantanos pueda ser considerada como un medio efectivo de estimular el crecimiento poblacional. DA - 2013/12// PY - 2013/12// DO - 10.1111/jofo.12035 VL - 84 IS - 4 SP - 355-366 SN - 1557-9263 KW - fire management KW - multistate occupancy KW - nest survival KW - nest video surveillance KW - Rallus elegans ER - TY - JOUR TI - Life and Death Sounds of Iceberg A53a AU - Dziak, Robert P. AU - Fowler, Matthew J. AU - Matsumoto, Haruyoshi AU - Bohnenstiehl, Delwayne R. AU - Park, Minkyu AU - Warren, Kyle AU - Lee, Won Sang T2 - OCEANOGRAPHY DA - 2013/6// PY - 2013/6// DO - 10.5670/oceanog.2013.20 VL - 26 IS - 2 SP - 10-12 SN - 1042-8275 ER - TY - JOUR TI - Evidence of Late Ediacaran Hyperextension of the Laurentian Iapetan Margin in the Birchy Complex, Baie Verte Peninsula, Northwest Newfoundland: Implications for the Opening of Iapetus, Formation of Peri-Laurentian Microcontinents and Taconic - Grampian Orogenesis AU - Staal, Cees R. AU - Chew, Dave M. AU - Zagorevski, Alexandre AU - McNicoll, Vicki AU - Hibbard, James AU - Skulski, Tom AU - Castonguay, Sebastien AU - Escayola, Monica P. AU - Sylvester, Paul J. T2 - GEOSCIENCE CANADA AB - The Birchy Complex of the Baie Verte Peninsula, northwestern Newfoundland, comprises an assemblage of mafic schist, ultramafic rocks, and metasedimentary rocks that are structurally sandwiched between overlying ca. 490 Ma ophiolite massifs of the Baie Verte oceanic tract and underlying metasedimentary rocks of the Fleur de Lys Supergroup of the Appalachian Humber margin. Birchy Complex gabbro yielded a Late Ediacaran U–Pb zircon ID–TIMS age of 558.3 ± 0.7 Ma, whereas gabbro and an intermediate tuffaceous schist yielded LA–ICPMS concordia zircon ages of 564 ± 7.5 Ma and 556 ± 4 Ma, respectively. These ages overlap the last phase of rift-related magmatism observed along the Humber margin of the northern Appalachians (565–550 Ma). The associated ultramafic rocks were exhumed by the Late Ediacaran and shed detritus into the interleaved sedimentary rocks. Psammite in the overlying Flat Point Formation yielded a detrital zircon population typical of the Laurentian Humber margin in the northern Appalachians. Age relationships and characteristics of the Birchy Complex and adjacent Rattling Brook Group suggest that the ultramafic rocks represent slices of continental lithospheric mantle exhumed onto the seafloor shortly before or coeval with magmatic accretion of mid-ocean ridge basalt-like mafic rocks. Hence, they represent the remnants of an ocean – continent transition zone formed during hyperextension of the Humber margin prior to establishment of a mid-ocean ridge farther outboard in the Iapetus Ocean. We propose that microcontinents such as Dashwoods and the Rattling Brook Group formed as a hanging wall block and an extensional crustal allochthon, respectively, analogous to the isolation of the Briançonnais block during the opening of the Alpine Ligurian–Piemonte and Valais oceanic seaways.SOMMAIRELe complexe de Birchy de la péninsule de Baie Verte, dans le nord-ouest de Terre-Neuve, est constitué d’un assemblage de schistes mafiques, de roches ultramafiques et de métasédiments qui sont coincés entre des massifs ophiolitiques d’ascendance océanique de la Baie Verte au-dessus, et des métasédiments du Supergroupe de Fleur de Lys de la marge de Humber des Appalaches en-dessous. Le complexe de gabbro de Birchy a donné une datation U-Pb sur zircon ID-TIMS correspondant à la fin de l’Édiacarien, soit 558,3 ± 0,7 Ma, alors qu’un gabbro et un schiste tufacé intermédiaire montrent une datation LA-ICP-MS Concordia sur zircon de 564 ± 7,5 Ma et 556 ± 4 Ma, respectivement. Ces datations chevauchent la dernière phase de magmatisme de rift observée le long de la marge Humber des Appalaches du Nord (565-550 Ma). Les roches ultramafiques associées ont été exhumées vers la fin de l’Édiacarien et leurs débris ont été imbriqués dans des roches sédimentaires. Les psammites de la Formation de Flat Point susjacente ont donné une population de zircons détritiques typique de la marge laurentienne de Humber des Appalaches du Nord. Les relations chronologiques et les caractéristiques du complexe de Birchy et du groupe de Rattling Brook adjacent, permettent de penser que ces roches ultramafiques pourraient être des écailles de manteau lithosphérique continental qui auraient été exhumées sur le plancher océanique peu avant ou en même temps que l’accrétion magmatique de roches mafiques basaltiques de type dorsale médio-océanique. Par conséquent, elles seraient des vestiges d’une zone de transition océan-continent formée au cours de l’hyper-extension de la marge de Humber avant l’apparition d’une dorsale médio-océanique plus loin au large dans l’océan Iapétus. Nous proposons que des microcontinents comme de Dashwoods et du groupe de Rattling Brook ont constitués respectivement un bloc de toit et un allochtone crustal d’extension, de la même manière que le bloc Briançonnais a été isolé lors de l’ouverture des bras océaniques alpins de Ligurie-Piémont et de Valais. DA - 2013/// PY - 2013/// DO - 10.12789/geocanj.2013.40.006 VL - 40 SP - 94-117 SN - 0315-0941 ER - TY - JOUR TI - The Genesis of African Easterly Waves by Upstream Development AU - Diaz, Michael AU - Aiyyer, Anantha T2 - JOURNAL OF THE ATMOSPHERIC SCIENCES AB - Abstract A genesis mechanism for African easterly waves (AEWs) is proposed. In the same manner that new troughs and ridges in the midlatitudes form downstream of existing ones through a mechanism known as downstream development, it is proposed that new AEWs can be generated upstream of existing AEWs. A local eddy kinetic energy budget of the AEW that ultimately became Hurricane Alberto (2000) demonstrates that upstream development explains its genesis more convincingly than previous theories of AEW genesis. The energetics and ageostrophic secondary circulation of a composite AEW are consistent with a new AEW forming as a result of this mechanism. Some strengths and weaknesses of upstream development as a paradigm for AEW genesis are discussed with respect to other potential mechanisms. DA - 2013/11// PY - 2013/11// DO - 10.1175/jas-d-12-0342.1 VL - 70 IS - 11 SP - 3492-3512 SN - 1520-0469 KW - Africa KW - Ageostrophic circulations KW - Rossby waves KW - Waves KW - atmospheric ER - TY - JOUR TI - STABLE ATMOSPHERIC BOUNDARY LAYERS AND DIURNAL CYCLES Challenges for Weather and Climate Models AU - Holtslag, A. A. M. AU - Svensson, G. AU - Baas, P. AU - Basu, S. AU - Beare, B. AU - Beljaars, A. C. M. AU - Bosveld, F. C. AU - Cuxart, J. AU - Lindvall, J. AU - Steeneveld, G. J. AU - Tjernstrom, M. AU - Wiel, B. J. H. T2 - BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY AB - The representation of the atmospheric boundary layer is an important part of weather and climate models and impacts many applications such as air quality and wind energy. Over the years, the performance in modeling 2-m temperature and 10-m wind speed has improved but errors are still significant. This is in particular the case under clear skies and low wind speed conditions at night as well as during winter in stably stratified conditions over land and ice. In this paper, the authors review these issues and provide an overview of the current understanding and model performance. Results from weather forecast and climate models are used to illustrate the state of the art as well as findings and recommendations from three intercomparison studies held within the Global Energy and Water Exchanges (GEWEX) Atmospheric Boundary Layer Study (GABLS). Within GABLS, the focus has been on the examination of the representation of the stable boundary layer and the diurnal cycle over land in clear-sky conditions. For this purpose, single-column versions of weather and climate models have been compared with observations, research models, and large-eddy simulations. The intercomparison cases are based on observations taken in the Arctic, Kansas, and Cabauw in the Netherlands. From these studies, we find that even for the noncloudy boundary layer important parameterization challenges remain. DA - 2013/11// PY - 2013/11// DO - 10.1175/bams-d-11-00187.1 VL - 94 IS - 11 SP - 1691-1706 SN - 1520-0477 ER - TY - JOUR TI - Photobleaching Response of Different Sources of Chromophoric Dissolved Organic Matter Exposed to Natural Solar Radiation Using Absorption and Excitation-Emission Matrix Spectra AU - Zhang, Yunlin AU - Liu, Xiaohan AU - Osburn, Christopher L. AU - Wang, Mingzhu AU - Qin, Boqiang AU - Zhou, Yongqiang T2 - PLOS ONE AB - CDOM biogeochemical cycle is driven by several physical and biological processes such as river input, biogeneration and photobleaching that act as primary sinks and sources of CDOM. Watershed-derived allochthonous (WDA) and phytoplankton-derived autochthonous (PDA) CDOM were exposed to 9 days of natural solar radiation to assess the photobleaching response of different CDOM sources, using absorption and fluorescence (excitation-emission matrix) spectroscopy. Our results showed a marked decrease in total dissolved nitrogen (TDN) concentration under natural sunlight exposure for both WDA and PDA CDOM, indicating photoproduction of ammonium from TDN. In contrast, photobleaching caused a marked increase in total dissolved phosphorus (TDP) concentration for both WDA and PDA CDOM. Thus TDN:TDP ratios decreased significantly both for WDA and PDA CDOM, which partially explained the seasonal dynamic of TDN:TDP ratio in Lake Taihu. Photobleaching rate of CDOM absorption a(254), was 0.032 m/MJ for WDA CDOM and 0.051 m/MJ for PDA CDOM from days 0-9, indicating that phototransformations were initially more rapid for the newly produced CDOM from phytoplankton than for the river CDOM. Extrapolation of these values to the field indicated that 3.9%-5.1% CDOM at the water surface was photobleached and mineralized every day in summer in Lake Taihu. Photobleaching caused the increase of spectral slope, spectral slope ratio and molecular size, indicating the CDOM mean molecular weight decrease which was favorable to further microbial degradation of mineralization. Three fluorescent components were validated in parallel factor analysis models calculated separately for WDA and PDA CDOM. Our study suggests that the humic-like fluorescence materials could be rapidly and easily photobleached for WDA and PDA CDOM, but the protein-like fluorescence materials was not photobleached and even increased from the transformation of the humic-like fluorescence substance to the protein-like fluorescence substance. Photobleaching was an important driver of CDOM and nutrients biogeochemistry in lake water. DA - 2013/10/25/ PY - 2013/10/25/ DO - 10.1371/journal.pone.0077515 VL - 8 IS - 10 SP - SN - 1932-6203 ER - TY - JOUR TI - Large-Scale Atmospheric and Oceanic Conditions during the 2011-12 DYNAMO Field Campaign AU - Gottschalck, Jon AU - Roundy, Paul E. AU - Schreck, Carl J., III AU - Vintzileos, Augustin AU - Zhang, Chidong T2 - MONTHLY WEATHER REVIEW AB - Abstract An international field campaign, Dynamics of the Madden Julian Oscillation (DYNAMO), took place in the Indian Ocean during October 2011–March 2012 to collect observations for the Madden–Julian oscillation (MJO), especially its convective initiation processes. The large-scale atmospheric and oceanic conditions during the campaign are documented here. The ENSO and the Indian Ocean dipole (IOD) states, the monthly mean monsoon circulation and its associated precipitation, humidity, vertical and meridional/zonal overturning cells, and ocean surface currents are discussed. The evolution of MJO events is described using various fields and indices that have been used to subdivide the campaign into three periods. These periods were 1) 17 September–8 December 2011 (period 1), which featured two robust MJO events that circumnavigated the global tropics with a period of less than 45 days; 2) 9 December 2011–31 January 2012, which contained less coherent activity (period 2); and 3) 1 February–12 April 2012, a period that featured the strongest and most slowly propagating MJO event of the campaign (period 3). Activities of convectively coupled atmospheric Kelvin and equatorial Rossby (ER) waves and their interaction with the MJO are discussed. The overview of the atmospheric and oceanic variability during the field campaign raises several scientific issues pertaining to our understanding of the MJO, or lack thereof. Among others, roles of Kelvin and ER waves in MJO convective initiation, convection-circulation decoupling on the MJO scale, applications of MJO filtering methods and indices, and ocean–atmosphere coupling need further research attention. DA - 2013/12// PY - 2013/12// DO - 10.1175/mwr-d-13-00022.1 VL - 141 IS - 12 SP - 4173-4196 SN - 1520-0493 KW - Madden-Julian oscillation KW - Intraseasonal variability ER - TY - JOUR TI - Fingerprinting the sources of suspended sediment delivery to a large municipal drinking water reservoir: Falls Lake, Neuse River, North Carolina, USA AU - Voli, Mark T. AU - Wegmann, Karl W. AU - Bohnenstiehl, DelWayne R. AU - Leithold, Elana AU - Osburn, Christopher L. AU - Polyakov, Viktor T2 - JOURNAL OF SOILS AND SEDIMENTS DA - 2013/12// PY - 2013/12// DO - 10.1007/s11368-013-0758-3 VL - 13 IS - 10 SP - 1692-1707 SN - 1614-7480 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84887284036&partnerID=MN8TOARS KW - Atlantic Piedmont KW - Nonpoint-source pollutant KW - Total maximum daily load KW - Total suspended sediments KW - Radiocarbon KW - Magnetic susceptibility ER - TY - JOUR TI - Eye-safe compact Raman light detection and ranging temperature profiler AU - Li, Guangkun AU - Schwemmer, Geary AU - Prasad, Coorg AU - Hwang, I. H. AU - Lei, Jie AU - Lee, Sangwoo AU - Prasad, Narasimha S. AU - Philbrick, Russell T2 - APPLIED OPTICS AB - The vertical profile of atmospheric temperature is a principal state variable to study atmospheric stability. A lidar system, constructed using a 355 nm Nd:YAG laser transmitter, measures the temperature profile using the rotational Raman technique. In comparison with traditional Raman lidar, the major innovations are the use of a low peak power and high repetition rate laser to achieve eye-safe operation in a compact reliable instrument and the use of an angle tuning filter to select operating wavelengths. We demonstrate the capability of both nighttime and daytime measurements as a step toward a future stand-alone capability for routine measurements of important meteorological properties in the lower atmosphere. DA - 2013/12/10/ PY - 2013/12/10/ DO - 10.1364/ao.52.008540 VL - 52 IS - 35 SP - 8540-8548 SN - 2155-3165 ER - TY - JOUR TI - Disparate Paths in the Geologic Evolution of the Northern and Southern Appalachians: A Case for Inherited Contrasting Crustal/Lithospheric Substrates AU - Hibbard, James AU - Karabinos, Paul T2 - GEOSCIENCE CANADA AB - Modern understanding of the tectonic evolution of the Appalachian orogen allows for recognition of most of the first-order lithotectonic elements and events of the mountain belt. Comparison of these features and events along the length of the orogen indicates that the northern and southern segments display distinct first-order differences. Contrasts between these segments existed from the onset of the Appalachian cycle. It has been recognized that Mesoproterozoic basement rock types south of approximately Pennsylvania are different from those to the north and more recently it has been shown that basement rocks in each area display distinct Nd and Pb isotopic signatures. Also, an early, ca. 770–680 Ma, Cryogenian stage of rifting is recorded in the southern Appalachians, but is not documented in the northern part of the orogen. During the Paleozoic Appalachian cycle, the accretion of peri-Gondwanan terranes was partitioned; Carolinia and Suwannee are confined to the southern Appalachians, and Ganderia, Avalonia, and Meguma to the northern Appalachians. Consequential to this partitioning, associated magmatism and some of the attendant tectonism is asymmetrically distributed between the two segments of the orogen. The terminal Appalachian collisional event, the Carboniferous Alleghanian orogeny, is distinctly different in the two segments of the orogen. The volumes of Alleghanian magmatic rocks in the northern and southern Appalachians are distributed asymmetrically and Carboniferous tectonic styles contrast sharply between the two regions. In addition, there is a modern first-order topographic change in the foreland of the orogeny. The southern foreland is characterized by a continuous, elevated plateau, whereas north of the New York promontory, foreland topography is more varied. Throughout the Appalachian cycle, all of these varied first-order changes occur in the vicinity of the New York promontory, suggesting that the promontory represents an enduring, fundamental boundary in the orogen. The nature and duration of differences between the northern and southern segments of the orogen indicate that this boundary was not an extrinsic ephemeral feature, such as a plate triple junction or hot spot. Rather, we suggest that an intrinsic difference in the Laurentian crustal/lithospheric(?) substrate present from the outset of the Appalachian cycle, as reflected by contrasts in the Mesoproterozoic basement in each segment, could be the root cause of these significant contrasts.SOMMAIREL’état actuel des connaissances sur l’évolution tectonique de l’orogène appalachien nous permet de reconnaître la plupart des éléments et des événements lithotectoniques de premier niveau de la chaîne de montagnes. La comparaison de ces caractéristiques et événements tout au long de l'orogène permet de distinguer des différences de premier ordre entre les segments nord et sud. Des contrastes entre ces segments ont existé depuis le début des Appalaches. Il a été reconnu que les roches de type socle du Mésoprotérozoïque à partir du sud de la Pennsylvanie environ, diffèrent de celles au nord, et plus récemment, il a été démontré que les roches de socle dans chacun de ces segments ont des signatures isotopiques Nd et Pb distinctes. En outre, un début de phase de distension au Cryogénien (770-680 Ma env.) est présent dans le segment sud des Appalaches, mais n'est pas documenté dans le segment nord de l'orogène. Durant le cycle paléozoïque des Appalaches, l'accrétion des terranes péri-Gondwana a été partagé; les terranes de Carolinia et de Suwannee sont confinés au segment sud des Appalaches, alors que ceux de Ganderia, d’Avalonie, et de Meguma sont confinés au segment nord des Appalaches. Conséquence de cette répartition, le magmatisme associé ainsi qu’une partie du diastrophisme relié sont répartis de manière asymétrique entre les deux segments de l'orogène. La phase terminale de collision des Appalaches, l'orogenèse Carbonifère alléghanienne, est nettement différente dans les deux segments de l'orogène. Les volumes des roches magmatiques alléghaniennes dans les Appalaches septentrionales et méridionales sont répartis de manière asymétrique et les styles tectoniques carbonifères contrastent fortement entre ces deux régions. En outre, on observe une différence topographique de premier ordre dans l’état actuel de l'avant-pays de l'orogenèse. Le segment sud de l'avant-pays est caractérisé par un plateau élevé continu, alors qu’au nord du promontoire de New York, la topographie d'avant-pays est plus diversifiée. Tout du long du cycle des Appalaches, tous ces changements variés de premier ordre existent au pourtour du promontoire de New York, ce qui permet de penser que le promontoire représente une frontière déterminante durable dans l'orogène. La nature et la persistance de ces différences entre les segments nord et sud de l'orogène indiquent que cette limite n'était pas une caractéristique éphémère extrinsèque, comme une jonction triple de plaque ou un point chaud. Nous suggérons plutôt qu'une différence intrinsèque dans la croûte/substrat lithosphérique(?) laurentien existait dès le début du cycle des Appalaches, comme en témoignent les contrastes dans le socle mésoprotérozoïque dans chaque segment, et pourrait être la cause de ces contrastes significatifs. DA - 2013/// PY - 2013/// DO - 10.12789/geocanj.2013.40.021 VL - 40 SP - 303-317 SN - 0315-0941 ER - TY - JOUR TI - Air-Sea Interactions and Marine Meteorology AU - Xie, Lian AU - Liu, Bin AU - Morrison, John AU - Gao, Huiwang AU - Wang, Jianhong T2 - ADVANCES IN METEOROLOGY DA - 2013/// PY - 2013/// DO - 10.1155/2013/162475 VL - 2013 SP - SN - 1687-9317 ER - TY - JOUR TI - A Modified Multivariate Madden-Julian Oscillation Index Using Velocity Potential AU - Ventrice, Michael J. AU - Wheeler, Matthew C. AU - Hendon, Harry H. AU - Schreck, Carl J., III AU - Thorncroft, Chris D. AU - Kiladis, George N. T2 - MONTHLY WEATHER REVIEW AB - Abstract A new Madden–Julian oscillation (MJO) index is developed from a combined empirical orthogonal function (EOF) analysis of meridionally averaged 200-hPa velocity potential (VP200), 200-hPa zonal wind (U200), and 850-hPa zonal wind (U850). Like the Wheeler–Hendon Real-time Multivariate MJO (RMM) index, which was developed in the same way except using outgoing longwave radiation (OLR) data instead of VP200, daily data are projected onto the leading pair of EOFs to produce the two-component index. This new index is called the velocity potential MJO (VPM) indices and its properties are quantitatively compared to RMM. Compared to the RMM index, the VPM index detects larger-amplitude MJO-associated signals during boreal summer. This includes a slightly stronger and more coherent modulation of Atlantic tropical cyclones. This result is attributed to the fact that velocity potential preferentially emphasizes the planetary-scale aspects of the divergent circulation, thereby spreading the convectively driven component of the MJO’s signal across the entire globe. VP200 thus deemphasizes the convective signal of the MJO over the Indian Ocean warm pool, where the OLR variability associated with the MJO is concentrated, and enhances the signal over the relatively drier longitudes of the equatorial Pacific and Atlantic. This work provides a useful framework for systematic analysis of the strengths and weaknesses of different MJO indices. DA - 2013/12// PY - 2013/12// DO - 10.1175/mwr-d-12-00327.1 VL - 141 IS - 12 SP - 4197-4210 SN - 1520-0493 KW - Indices KW - Madden-Julian oscillation KW - Empirical orthogonal functions KW - Intraseasonal variability KW - Tropical variability ER - TY - JOUR TI - The generation and propagation of internal solitary waves in the South China Sea AU - Chen, Ying-Jung AU - Ko, Dong Shan AU - Shaw, Ping-Tung T2 - JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS AB - The internal wave field in the real‐time numerical simulation at the Naval Research Laboratory is analyzed during April–May 2007, a period of intensive field observations in the northern South China Sea. Internal solitary waves are detected in the plots of the surface baroclinic velocity and depth‐integrated energy flux. In each diurnal cycle, an internal wave crest with eastward surface velocity arrives at a location west of the Luzon Strait first and is followed by two internal wave troughs of westward surface velocity, in agreement with the arrival of a type‐B and then a type‐A internal solitary wave described in the literature. Sources of the B‐wave and A‐wave are consistent with the generation by eastward tidal currents on the western and eastern ridges in the Luzon Strait, respectively. During neap tide, a B‐wave and an A‐wave switch their daily arrival times to maintain the arrival sequence of an A‐wave after a B‐wave. Internal waves arriving at a mooring location at the same time each day are B‐waves during the neap tide and A‐waves during the first half of the spring tide. Otherwise, both A‐waves and B‐waves have a 1 h delay each day in their daily arrivals. Classification of the internal wave types based on generation gives a coherent pattern of internal wave propagation from the generation region to the continental margin in the South China Sea. The propagation speeds of both waves are higher than that of linear internal waves. DA - 2013/12// PY - 2013/12// DO - 10.1002/2013jc009319 VL - 118 IS - 12 SP - 6578-6589 SN - 2169-9291 KW - internal wave KW - wave generation KW - wave propagation KW - South China Sea ER - TY - JOUR TI - Ship-Based Observations of the Diurnal Cycle of Southeast Pacific Marine Stratocumulus Clouds and Precipitation AU - Burleyson, Casey D. AU - Szoeke, Simon P. AU - Yuter, Sandra E. AU - Wilbanks, Matt AU - Brewer, W. Alan T2 - JOURNAL OF THE ATMOSPHERIC SCIENCES AB - Abstract The diurnal cycle of marine stratocumulus in cloud-topped boundary layers is examined using ship-based meteorological data obtained during the 2008 Variability of American Monsoon Systems (VAMOS) Ocean–Cloud–Atmosphere–Land Study Regional Experiment (VOCALS-REx). The high temporal and spatial continuity of the ship data, as well as the 31-day sample size, allows the diurnal transition in degree of coupling of the stratocumulus-topped boundary layer to be resolved. The amplitude of diurnal variation was comparable to the magnitude of longitudinal differences between regions east and west of 80°W for most of the cloud, surface, and precipitation variables examined. The diurnal cycle of precipitation is examined in terms of areal coverage, number of drizzle cells, and estimated rain rate. East of 80°W, the drizzle cell frequency and drizzle area peaks just prior to sunrise. West of 80°W, total drizzle area peaks at 0300 local solar time (LST), 2–3 h before sunrise. Peak drizzle cell frequency is 3 times higher west of 80°W compared to east of 80°W. The waning of drizzle several hours prior to the ramp up of shortwave fluxes may be related to the higher peak drizzle frequencies in the west. The ensemble effect of localized subcloud evaporation of precipitation may make drizzle a self-limiting process where the areal density of drizzle cells is sufficiently high. The daytime reduction in vertical velocity variance in a less coupled boundary layer is accompanied by enhanced stratification of potential temperature and a buildup of moisture near the surface. DA - 2013/12// PY - 2013/12// DO - 10.1175/jas-d-13-01.1 VL - 70 IS - 12 SP - 3876-3894 SN - 1520-0469 ER - TY - JOUR TI - Resonance enhanced Raman scatter in liquid benzene at vapor-phase absorption peaks AU - Willitsford, A. AU - Chadwick, C. T. AU - Hallen, H. AU - Kurtz, S. AU - Philbrick, C. R. T2 - Optics Express DA - 2013/// PY - 2013/// VL - 21 IS - 22 SP - 26150-26161 ER - TY - JOUR TI - Predicting the distribution of oceanic-stage Kemp's ridley sea turtles AU - Putman, Nathan F AU - Mansfield, Katherine L AU - He, Ruoying AU - Shaver, Donna J AU - Verley, Philippe T2 - Biology letters DA - 2013/// PY - 2013/// VL - 9 IS - 5 SP - 20130345 ER - TY - JOUR TI - On improving storm surge forecasting using an adjoint optimal technique AU - Li, Yineng AU - Peng, Shiqiu AU - Yan, Jing AU - Xie, Lian T2 - OCEAN MODELLING AB - A three-dimensional ocean model and its adjoint model are used to simultaneously optimize the initial conditions (IC) and the wind stress drag coefficient (Cd) for improving storm surge forecasting. To demonstrate the effect of this proposed method, a number of identical twin experiments (ITEs) with a prescription of different error sources and two real data assimilation experiments are performed. Results from both the idealized and real data assimilation experiments show that adjusting IC and Cd simultaneously can achieve much more improvements in storm surge forecasting than adjusting IC or Cd only. A diagnosis on the dynamical balance indicates that adjusting IC only may introduce unrealistic oscillations out of the assimilation window, which can be suppressed by the adjustment of the wind stress when simultaneously adjusting IC and Cd. Therefore, it is recommended to simultaneously adjust IC and Cd to improve storm surge forecasting using an adjoint technique. DA - 2013/12// PY - 2013/12// DO - 10.1016/j.ocemod.2013.08.009 VL - 72 SP - 185-197 SN - 1463-5011 KW - 4DVAR KW - Ajoint model KW - Wind stress drag coefficient KW - Initial conditions KW - Storm surge forecasts ER - TY - JOUR TI - Modeling ocean circulation and biogeochemical variability in the Gulf of Mexico AU - Xue, Zuo AU - He, Ruoying AU - Fennel, Katja AU - Cai, W-J AU - Lohrenz, Steven AU - Hopkinson, C T2 - Biogeosciences DA - 2013/// PY - 2013/// VL - 10 IS - 11 SP - 7219 ER - TY - JOUR TI - Atlantic Hurricanes and Climate Change. Part II: Role of Thermodynamic Changes in Decreased Hurricane Frequency AU - Mallard, Megan S. AU - Lackmann, Gary M. AU - Aiyyer, Anantha T2 - JOURNAL OF CLIMATE AB - Abstract A method of downscaling that isolates the effect of temperature and moisture changes on tropical cyclone (TC) activity was presented in Part I of this study. By applying thermodynamic modifications to analyzed initial and boundary conditions from past TC seasons, initial disturbances and the strength of synoptic-scale vertical wind shear are preserved in future simulations. This experimental design allows comparison of TC genesis events in the same synoptic setting, but in current and future thermodynamic environments. Simulations of both an active (September 2005) and inactive (September 2009) portion of past hurricane seasons are presented. An ensemble of high-resolution simulations projects reductions in ensemble-average TC counts between 18% and 24%, consistent with previous studies. Robust decreases in TC and hurricane counts are simulated with 18- and 6-km grid lengths, for both active and inactive periods. Physical processes responsible for reduced activity are examined through comparison of monthly and spatially averaged genesis-relevant parameters, as well as case studies of development of corresponding initial disturbances in current and future thermodynamic conditions. These case studies show that reductions in TC counts are due to the presence of incipient disturbances in marginal moisture environments, where increases in the moist entropy saturation deficits in future conditions preclude genesis for some disturbances. Increased convective inhibition and reduced vertical velocity are also found in the future environment. It is concluded that a robust decrease in TC frequency can result from thermodynamic changes alone, without modification of vertical wind shear or the number of incipient disturbances. DA - 2013/11// PY - 2013/11// DO - 10.1175/jcli-d-12-00183.1 VL - 26 IS - 21 SP - 8513-8528 SN - 1520-0442 KW - Hurricanes KW - Tropical cyclones KW - Climate change KW - Hurricanes KW - typhoons KW - General circulation models KW - Mesoscale models ER - TY - JOUR TI - Toward rigorous use of expert knowledge in ecological research AU - Drescher, M. AU - Perera, A. H. AU - Johnson, C. J. AU - Buse, L. J. AU - Drew, C. A. AU - Burgman, M. A. T2 - Ecosphere DA - 2013/// PY - 2013/// VL - 4 IS - 7 ER - TY - JOUR TI - Sr, Nd, Hf and Pb isotope systematics of postshield-stage lavas at Kahoolawe, Hawaii AU - Huang, Shichun AU - Blichert-Toft, Janne AU - Fodor, R. V. AU - Bauer, Glenn R. AU - Bizimis, Michael T2 - CHEMICAL GEOLOGY AB - We report high-precision Sr, Nd, Hf and Pb isotope compositions for twenty-one postshield-stage and two post-caldera lavas from Kahoolawe, a Loa-trend Hawaiian volcano. Kahoolawe postshield- and shield-stage lavas have overlapping though highly heterogeneous Sr, Nd, Hf and Pb isotope compositions, implying that the shield- and postshield-stage volcanism at Kahoolawe sampled the same isotopically heterogeneous mantle source. This differs from that of most other Hawaiian volcanoes, such as Haleakala, Mauna Kea, and Hualalai, whose shield-to-postshield transitions are characterized by shifts to lower 87Sr/86Sr and higher 143Nd/144Nd. There are correlations between CaO, Sc and V contents and radiogenic isotope compositions within Kahoolawe postshield-stage lavas. For example, Sc abundance is negatively correlated with 87Sr/86Sr, and positively correlated with εNd and εHf; V abundance is positively correlated with εNd, εHf, and 206Pb/204Pb. Element-isotope correlations are also observed in Mauna Kea postshield-stage lavas: Sc and V abundances are negatively correlated with εHf and 206Pb/204Pb, and positively correlated with εNd. These trends may be due to magma–magma mixing. That is, in addition to clinopyroxene fractionation to account for the low CaO, Sc and V contents in some postshield-stage lavas, partial melts of eclogite/garnet pyroxenite, characterized by low CaO, Sc and V contents, may also be part of the petrogenesis of Kahoolawe postshield-stage lavas. It is well established that lavas erupted at the geographically defined Loa- and Kea-trend volcanoes have different isotopic and geochemical compositions. Specifically, compared to the Kea-trend lavas, Loa-trend lavas have higher 208Pb/204Pb at a given 206Pb/204Pb. However, cases exist of both shield- and postshield-stage volcanism where Kea-type isotopic signatures are present in Loa-trend volcanoes and the reverse. We propose that Loa- and Kea-type source components are present beneath both Loa- and Kea-trend volcanoes in such a way that the average source compositions of Loa-trend volcanoes have a Loa-type isotopic signature, and that of the Kea-trend volcanoes have a Kea-type isotopic signature. When the size of the magma capture zone is much larger than that of the source components, the erupted lavas have the average compositions of the source. If the size of the magma capture zone is comparable to that of the source components, the erupted lavas could have either Loa- or Kea-type isotopic signatures. DA - 2013/12/18/ PY - 2013/12/18/ DO - 10.1016/j.chemgeo.2013.10.021 VL - 360 SP - 159-172 SN - 1872-6836 KW - Hawaii KW - Mantle plume KW - Sr, Nd, Hf and Pb isotopes KW - Postshield volcanism ER - TY - JOUR TI - Signals of watershed change preserved in organic carbon buried on the continental margin seaward of the Waipaoa River, New Zealand AU - Leithold, Elana L. AU - Blair, Neal E. AU - Childress, Laurel B. AU - Brulet, Benjamin R. AU - Marden, Michael AU - Orpin, Alan R. AU - Kuehl, Steven A. AU - Alexander, Clark R. T2 - MARINE GEOLOGY AB - Abstract Holocene sediments buried on the continental shelf seaward of the Waipaoa River, northeastern New Zealand, preserve a stratigraphic record of terrestrial environmental change. The well characterized, long-term record of storms, volcanism, and human disturbance in this region provides an opportunity to examine how such changes are reflected in the character of organic carbon (OC) buried on the continental margin. Complimentary evidence obtained from analyses of the 14 C content and the elemental and stable carbon isotopic composition of different sedimentary fractions, including charcoal, wood, and clay-sized isolates, indicates that these perturbations led to mobilization of OC components with variable storage histories in the watershed. Charcoal transported in the modern Waipaoa River and buried in offshore depocenters includes a highly aged component that has apparently been slowly released from storage in soil or alluvial terraces. The charcoal fraction ages become dramatically younger in sediments deposited after the Taupo volcanic eruption (1717 cal yr BP) and then Polynesian settlement (ca. 700 cal yr BP), both signaling biomass burning. The mean age of woody plant fragments and clay-bound OC deposited on the shelf also varies over time, with older material having accumulated in the middle Holocene and since human occupation. Deposition of older-than-average wood fragments and clay-bound OC between about 5 and 3.6 kyr BP correlates with evidence for a period of increased storm frequency in the region and may reflect the enhanced delivery of aged soil and sedimentary rock mobilized from hill slopes via earthflows and/or deep seated landslides. Similarly, the deposition of older wood and clay-bound OC commensurate with the first anthropogenic disturbance ca. 700 years ago is consistent with accelerated mass wasting due to deforestation. At the same time, a change in the elemental and stable isotopic composition of bulk and clay-bound OC buried on the shelf may reflect increased marine primary productivity and/or mobilization of OC from deep levels in soil profiles. Deforestation of the Waipaoa headwaters by European settlers beginning in the middle 19th century is evinced by a sharper rise in the age of clay associated OC buried offshore. Today, deep gully incision into fractured sedimentary bedrock is a major source of sediment and kerogen to the river, and this process has left its mark on the age of sedimentary OC delivered to the adjacent margin. DA - 2013/12/1/ PY - 2013/12/1/ DO - 10.1016/j.margeo.2013.10.007 VL - 346 SP - 355-365 SN - 1872-6151 KW - continental margin KW - sediments KW - watershed change KW - radiocarbon KW - carbon isotopes KW - New Zealand KW - anthropogenic change ER - TY - JOUR TI - Oyster Larvae Settle in Response to Habitat-Associated Underwater Sounds AU - Lillis, Ashlee AU - Eggleston, David B. AU - Bohnenstiehl, DelWayne R. T2 - PLOS ONE AB - Following a planktonic dispersal period of days to months, the larvae of benthic marine organisms must locate suitable seafloor habitat in which to settle and metamorphose. For animals that are sessile or sedentary as adults, settlement onto substrates that are adequate for survival and reproduction is particularly critical, yet represents a challenge since patchily distributed settlement sites may be difficult to find along a coast or within an estuary. Recent studies have demonstrated that the underwater soundscape, the distinct sounds that emanate from habitats and contain information about their biological and physical characteristics, may serve as broad-scale environmental cue for marine larvae to find satisfactory settlement sites. Here, we contrast the acoustic characteristics of oyster reef and off-reef soft bottoms, and investigate the effect of habitat-associated estuarine sound on the settlement patterns of an economically and ecologically important reef-building bivalve, the Eastern oyster (Crassostrea virginica). Subtidal oyster reefs in coastal North Carolina, USA show distinct acoustic signatures compared to adjacent off-reef soft bottom habitats, characterized by consistently higher levels of sound in the 1.5-20 kHz range. Manipulative laboratory playback experiments found increased settlement in larval oyster cultures exposed to oyster reef sound compared to unstructured soft bottom sound or no sound treatments. In field experiments, ambient reef sound produced higher levels of oyster settlement in larval cultures than did off-reef sound treatments. The results suggest that oyster larvae have the ability to respond to sounds indicative of optimal settlement sites, and this is the first evidence that habitat-related differences in estuarine sounds influence the settlement of a mollusk. Habitat-specific sound characteristics may represent an important settlement and habitat selection cue for estuarine invertebrates and could play a role in driving settlement and recruitment patterns in marine communities. DA - 2013/10/30/ PY - 2013/10/30/ DO - 10.1371/journal.pone.0079337 VL - 8 IS - 10 SP - SN - 1932-6203 ER - TY - JOUR TI - Observed frequency and intensity of tropical precipitation from instantaneous estimates AU - Biasutti, Michela AU - Yuter, Sandra E. T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Negative societal impacts can result from intense individual downpours, the accumulation of rainfall over a day or more, or a combination of these. Accumulation is reasonably well captured by daily reporting rain gauges, but rainfall intensity is not. Ten years of data from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) are used to describe the spatial and seasonal distributions of instantaneous rainfall intensity with an emphasis on how these differ from the distributions of mean daily accumulation. Over tropical land, the rainy season, when rainfall is most frequent, does not coincide with the highest mean intensity. Rather, intensity peaks just before the rainy season. This offset is most obvious in the pre‐onset and post‐onset months in monsoon regions and it is also evident in equatorial regions without a well‐defined dry and rainy season. Most seasonal variations in rainfall intensity can be explained as parallel variations in the occurrence of convective, relative to stratiform, precipitation. However, regional differences in rainfall intensity are related to differences in the intensity of convection itself. Compared with seasonal changes in intensity over land, variations in convective precipitation fraction over tropical oceans are trivial, and the modest seasonal changes in the intensity of rainfall parallel those of frequency. These findings suggest that studies of precipitation extremes under global warming should (1) explicitly tackle the question of changes in the intensity of rainfall separately from changes in daily rainfall accumulation and (2) consider the different qualities of extreme precipitation events over ocean and over land. DA - 2013/9/16/ PY - 2013/9/16/ DO - 10.1002/jgrd.50694 VL - 118 IS - 17 SP - 9534-9551 SN - 2169-8996 KW - tropical rainfall KW - seasonal cycle KW - convective processes KW - TRMM ER - TY - JOUR TI - Minimal cooling rate dependence of ice nuclei activity in the immersion mode AU - Wright, Timothy P. AU - Petters, Markus D. AU - Hader, John D. AU - Morton, Travis AU - Holder, Amara L. T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Abstract We present new measurements of the time dependence of the ice‐nucleating ability of a wide range of materials including the minerals montmorillonite and kaolinite, the biological proxy ice nuclei Icemax, and flame soot generated from the incomplete combustion of ethylene gas. We also present time dependence for ambient ice nuclei collected from rainwater samples. Our data show that the time dependence for all materials studied here is weak, suggesting that the modified singular approximation is valid over the range of times and temperatures encountered for mixed phase clouds. DA - 2013/9/27/ PY - 2013/9/27/ DO - 10.1002/jgrd.50810 VL - 118 IS - 18 SP - 10535-10543 SN - 2169-8996 ER - TY - JOUR TI - Mesoscale eddies in the South Atlantic Bight AU - Castelao, Renato M. AU - He, Ruoying T2 - JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS AB - [1] Satellite-derived sea level anomaly fields constructed by combining measurements from simultaneously operating altimeters are used to quantify properties and propagation characteristics of eddies in the South Atlantic Bight (SAB). Eddy detection and eddy tracking algorithms are applied to 19 years of high-resolution observations available at weekly intervals. Inshore of the 800 m isobath, eddies are most frequently observed at and downstream of the Charleston Bump (a major topographic feature located at 31–32°N), a region where the amplitude of most eddies is increased. The bump is also a preferred region for eddy generation. The amplitude of eddies is found to increase with water depth. Eddies generated in the SAB tend to propagate westward toward the coast and to the northeast, presumably due to the influence of the strong mean northeastward flow of the Gulf Stream. Those eddies are highly nonlinear, with potential to trap water in their interior as they propagate. Since a large fraction of the eddies that at some point in their histories are found inshore of the 800 m isobath experience large bathymetric changes along their trajectories, they can potentially serve as efficient mechanisms for cross-isobath transport in the SAB. Analysis of temporal variability in eddy activity suggests that cross-isobath transport due to nonlinear eddies may be significant during all seasons, but will likely be characterized by large interannual variability. DA - 2013/10// PY - 2013/10// DO - 10.1002/jgrc.20415 VL - 118 IS - 10 SP - 5720-5731 SN - 2169-9291 KW - South Atlantic Bight KW - eddies KW - cross-isobath transport KW - altimeter ER - TY - JOUR TI - Fine Scale Modeling of Agricultural Air Quality over the Southeastern United States Using Two Air Quality Models. Part II. Sensitivity Studies and Policy Implications AU - Zhang, Yang AU - Wu, Shiang-Yuh T2 - AEROSOL AND AIR QUALITY RESEARCH AB - Sensitivity simulations using CMAQ at various grid resolutions are evaluated. Compared with the simulations at 12- and 4-km, the 1.33-km simulation shows large improvement in most meteorological predictions in July and some chemical predictions in January and July 2002. Limited improvements at 1.33-km and 4-km are attributed to current limitations in meteorological parameterizations and lack of accurate data for land use and emissions at a fine scale. NH3 plays an important role in PM2.5 formation, but the emission control strategies focus only on SO2 and NOx in the southeastern U.S. To understand the impact of NH3, NH3 to NH4+ conversion and the chemical regimes of PM2.5 formation are examined. The conversion rates of NH3 to NH4+ from CMAQ and CAMx simulations are 10–60% in January and 10–50% in July at and near major sources. The eastern North Carolina and northeastern Georgia are NH3-rich and the remaining areas are NH3-neutral in both months. To further assess the impact of NH3 emission reductions, the sensitivity of CMAQ to emission reductions is evaluated for four emission scenarios: reducing emissions of SO2, NOx, agricultural livestock-NH3 (AL-NH3) by 50%, respectively and collectively. The largest reductions of PM2.5 are by up to 19.2% in January and 18.3% in July when all these emissions are reduced by 50%. AL-NH3 reductions result in the largest decrease in January by up to 16%, dominated by a reduction in NH4NO3, while SO2 reductions result in the largest decrease in July (up to 11%) due to decreases in NH4+ and SO42–. This indicates that reducing AL-NH3 emissions together with SO2 and NOx emissions can reduce PM2.5 concentrations more than reducing emissions of SO2 and NOx alone, particularly in winter. Future emission control strategies for PM2.5 controlling should consider the reduction of NH3 emissions, in addition to the emissions of SO2 and NOx. DA - 2013/10// PY - 2013/10// DO - 10.4209/aaqr.2012.12.0347 VL - 13 IS - 5 SP - 1475-1491 SN - 2071-1409 KW - CMAQ KW - CAMx KW - Sensitivity simulation KW - Emission reduction KW - Fine scale modeling ER - TY - CONF TI - Coherence in UV resonance Raman spectroscopy of liquid benzene and toluene, but not ice AU - Hallen, H. D. AU - Neely, R. R. AU - Willitsford, A. H. AU - Chadwick, C. T. AU - Philbrick, C. R. C2 - 2013/// C3 - Ultrafast imaging and spectroscopy DA - 2013/// VL - 8845 ER - TY - JOUR TI - Space-Time Cube Representation of Stream Bank Evolution Mapped by Terrestrial Laser Scanning AU - Starek, M. J. AU - Mitasova, H. AU - Wegmann, K. W. AU - Lyons, N. T2 - IEEE GEOSCIENCE AND REMOTE SENSING LETTERS AB - Terrestrial laser scanning (TLS) is utilized to monitor bank erosion along a stream that has incised through historic millpond (legacy) sediment. A processing workflow is developed to generate digital terrain models (DTMs) of the bank's surface from the TLS point cloud data. Differencing of the DTMs reveals that the majority of sediment loss stems from the legacy sediment layer. The DTM time series is stacked into a voxel model to form a space-time cube (STC). The STC provides a compact representation of the bank's spatiotemporal evolution captured by the TLS scans. The continuous STC extends this approach by generating a voxel model with equal temporal resolution directly from the point cloud data. Novel visualizations are extracted from the STCs to explore patterns in surface evolution. Results show that erosion is highly variable in space and time, with large-scale erosion being episodic due to bank failure within legacy sediment. DA - 2013/11// PY - 2013/11// DO - 10.1109/lgrs.2013.2241730 VL - 10 IS - 6 SP - 1369-1373 SN - 1558-0571 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84886592528&partnerID=MN8TOARS KW - GRASS GIS KW - legacy sediment KW - lidar point cloud KW - stream erosion KW - voxel model ER - TY - JOUR TI - Source and magnitude of error in an inexpensive image-based water level measurement system AU - Gilmore, Troy E. AU - Birgand, Francois AU - Chapman, Kenneth W. T2 - JOURNAL OF HYDROLOGY AB - Recent technological advances have opened the possibility to use webcams and images as part of the environmental monitoring arsenal. The potential sources and magnitude of uncertainties inherent to an image-based water level measurement system are evaluated in an experimental design in the laboratory. Sources of error investigated include image resolution, lighting effects, perspective, lens distortion and water meniscus. Image resolution and meniscus were found to weigh the most in the overall uncertainty of this system. Image distortion, although largely taken into account by the software developed, may also significantly add to uncertainty. Results suggest that “flat” images with little distortion are preferable. After correction for the water meniscus, images captured with a camera (12 mm or 16 mm focal lengths) positioned 4–7 m from the water level edge have the potential to yield water level measurements within ±3 mm when using this technique. DA - 2013/7/24/ PY - 2013/7/24/ DO - 10.1016/j.jhydrol.2013.05.011 VL - 496 SP - 178-186 SN - 1879-2707 KW - Water level KW - Water stage KW - Machine vision KW - Edge detection KW - Instrument comparison KW - Uncertainty ER - TY - JOUR TI - Small-scale temporal and spatial variations in protistan community composition at the San Pedro Ocean Time-series station off the coast of southern California AU - Lie, Alle A. Y. AU - Kim, Diane Y. AU - Schnetzer, Astrid AU - Caron, David A. T2 - AQUATIC MICROBIAL ECOLOGY AB - AME Aquatic Microbial Ecology Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials AME 70:93-110 (2013) - DOI: https://doi.org/10.3354/ame01652 FEATURE ARTICLE Small-scale temporal and spatial variations in protistan community composition at the San Pedro Ocean Time-series station off the coast of southern California Alle A. Y. Lie1,*, Diane Y. Kim1, Astrid Schnetzer2, David A. Caron1 1Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Los Angeles, California 90089-0371, USA 2Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, 2800 Faucette Drive, 4148 Raleigh, North Carolina 27695, USA *Email: alie@usc.edu ABSTRACT: Small-scale spatial and temporal variabiliy in protistan community composition was investigated at the USC San Pedro Ocean Time-series (SPOT) station and contrasted with a 10 yr (2000 to 2010) dataset of samples collected at approximately monthly intervals from the same station. Surface seawater samples were collected for 12 consecutive days at the SPOT station, and an additional 17 stations (16 within a grid surrounding the SPOT station and 1 outlying station; 2 to 21 km apart) were sampled during 1 of the 12 sampling days, to investigate the small-scale temporal and spatial variability, respectively. Terminal restriction fragment length polymorphism (T‑RFLP) analysis of the 18S rRNA gene was used to generate DNA fingerprints of the protistan community, which were used for the calculation of pair-wise Bray-Curtis and Jaccard similarity values at different spatial and temporal scales. Temperature, salinity, pH, wind, and upwelling did not appear to have any significant effect on community composition, and distance had a weak correlation with the similarity indices generated from spatial samples. Communities separated by the smallest spatial scales (0 to 2 km) had significantly higher average similarity than communities separated by small temporal scales (1 to 9 d). Comparisons with a 10 yr dataset of monthly samples revealed significantly lower average similarity values among communities separated by time periods ≥ 1 mo (45 to 52%) compared to communities separated by the smallest spatial (0 to 2 km; 67 to 71%) and temporal (1 d; 64%) scales. Our results indicate that small-scale spatial and day-to-day variability of protistan communities was overshadowed by monthly, seasonal, and interannual variabilities. KEY WORDS: Protists · Microbial eukaryotes · Time-series · Spatial variability · Temporal variability · T-RFLP Full text in pdf format Information about this Feature Article Supplementary material NextCite this article as: Lie AAY, Kim DY, Schnetzer A, Caron DA (2013) Small-scale temporal and spatial variations in protistan community composition at the San Pedro Ocean Time-series station off the coast of southern California. Aquat Microb Ecol 70:93-110. https://doi.org/10.3354/ame01652 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AME Vol. 70, No. 2. Online publication date: August 22, 2013 Print ISSN: 0948-3055; Online ISSN: 1616-1564 Copyright © 2013 Inter-Research. DA - 2013/// PY - 2013/// DO - 10.3354/ame01652 VL - 70 IS - 2 SP - 93-+ SN - 1616-1564 KW - Protists KW - Microbial eukaryotes KW - Time-series KW - Spatial variability KW - Temporal variability KW - T-RFLP ER - TY - JOUR TI - On the sensitivity of hurricane storm surge simulation to domain size AU - Li, Rui AU - Xie, Lian AU - Liu, Bin AU - Guan, Changlong T2 - OCEAN MODELLING AB - The impact of model domain size on the simulated storm surge under various hurricane and topographic conditions is investigated by using a three-dimensional storm surge model. Idealized experiments are designed to simulate storm surge with different domain sizes under various hurricane intensities, radius of maximum wind (RMW), translation speeds and landfall directions, coastal ocean bottom slopes, and continental shelf extents. The results show that, in general, the simulated storm surge first increases with increasing domain size and then approaches a constant value. A “threshold domain size” is defined accordingly, so that differences among model results with different domain sizes larger than the threshold domain size are negligible. The threshold domain size is shown to be insensitive to hurricane intensities, but increases linearly with increasing hurricane RMWs. It also increases with increasing translation speeds and decreasing bottom slopes, when hurricanes approach land perpendicularly. The threshold domain size can also be affected by other factors such as the direction of the storm track of a landfalling hurricane and the extent of continental shelf. Considering the complex dependence of the threshold domain size on various hurricane parameters, a polar graphic chart is created for estimating the threshold domain size for possible hurricane landfall directions and RMWs. A real case study of hurricane Charley (2004) is conducted with different domain sizes. Model results indicate that the threshold domain size estimated from the idealized experiments is reasonable for practical applications. DA - 2013/7// PY - 2013/7// DO - 10.1016/j.ocemod.2013.03.005 VL - 67 SP - 1-12 SN - 1463-5011 KW - Storm surge KW - Domain size KW - Hurricane KW - Threshold domain size ER - TY - JOUR TI - Observed Microphysical Evolution for Two East Coast Winter Storms and the Associated Snow Bands AU - Stark, David AU - Colle, Brian A. AU - Yuter, Sandra E. T2 - MONTHLY WEATHER REVIEW AB - Abstract This paper presents the observed microphysical evolution of two coastal extratropical cyclones (19–20 December 2009 and 12 January 2011) and the associated passage of heavy snowbands in the cyclone comma head. The observations were made approximately 93 km east of New York City at Stony Brook, New York. Surface microphysical measurements of snow habit and degree of riming were taken every 15–30 min using a stereo microscope and camera, and snow depth and snow density were also recorded. A vertically pointing Ku-band radar observed the vertical evolution of reflectivity and Doppler vertical velocities. There were rapid variations in the snow habits and densities related to the changes in vertical motion and depth of saturation. At any one time, a mixture of different ice habits was observed. Certain ice habits were dominant at the surface when the maximum vertical motion aloft occurred at their favored temperature for depositional growth. Convective seeder cells above 4 km MSL resulted in relatively cold (less than −15°C) ice crystal habits (side planes, bullets, and dendrites). Needlelike crystals were prevalent during the preband period when the maximum vertical motion was in the layer from −5° to −10°C. Moderately rimed dendritic crystals were observed at snowband maturity associated with the strongest frontogenetical ascent on the warm (east) side of the bands. Riming rapidly decreased and more platelike crystals became more numerous as the strongest ascent moved east of Stony Brook. Snow-to-liquid density ratios ranged from 8:1 to 13:1 in both events, except during the period of graupel, when the ratio was as low as 4:1. DA - 2013/6// PY - 2013/6// DO - 10.1175/mwr-d-12-00276.1 VL - 141 IS - 6 SP - 2037-2057 SN - 0027-0644 ER - TY - JOUR TI - Observation and Analysis of Particle Nucleation at a Forest Site in Southeastern US AU - Pillai, Priya AU - Khlystov, Andrey AU - Walker, John AU - Aneja, Viney T2 - ATMOSPHERE AB - This study examines the characteristics of new particle formation at a forest site in southeastern US. Particle size distributions above a Loblolly pine plantation were measured between November 2005 and September 2007 and analyzed by event type and frequency, as well as in relation to meteorological and atmospheric chemical conditions. Nucleation events occurred on 69% of classifiable observation days. Nucleation frequency was highest in spring. The highest daily nucleation (class A and B events) frequency (81%) was observed in April. The average total particle number concentration on nucleation days was 8,684 cm−3 (10 < Dp < 250 nm) and 3,991 cm−3 (10 < Dp < 25 nm) with a mode diameter of 28 nm with corresponding values on non-nucleation days of 2,143 cm−3, 655 cm−3, and 44.5 nm, respectively. The annual average growth rate during nucleation events was 2.7 ± 0.3 nm·h−1. Higher growth rates were observed during summer months with highest rates observed in May (5.0 ± 3.6 nm·h−1). Winter months were associated with lower growth rates, the lowest occurring in February (1.2 ± 2.2 nm·h−1). Consistent with other studies, nucleation events were more likely to occur on days with higher radiative flux and lower relative humidity compared to non-nucleation days. The daily minimum in the condensation sink, which typically occurred 2 to 3 h after sunrise, was a good indicator of the timing of nucleation onset. The intensity of the event, indicated by the total particle number concentration, was well correlated with photo-synthetically active radiation, used here as a surrogate for total global radiation, and relative humidity. Even though the role of biogenic VOC in the initial nuclei formation is not understood from this study, the relationships with chemical precursors and secondary aerosol products associated with nucleation, coupled with diurnal boundary layer dynamics and seasonal meteorological patterns, suggest that H2SO4 and biogenic VOC play a role in nucleated particle growth at this site. DA - 2013/6// PY - 2013/6// DO - 10.3390/atmos4020072 VL - 4 IS - 2 SP - 72-93 SN - 2073-4433 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84885125385&partnerID=MN8TOARS KW - nucleation KW - particle size distribution KW - SMPS KW - DMA KW - CPC KW - nucleation frequency KW - biogenic VOC KW - condensation sink KW - PAR KW - growth rate ER - TY - JOUR TI - Message from the Technical Editor-in-Chief AU - Rao, S. Trivikrama T2 - JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION DA - 2013/1/1/ PY - 2013/1/1/ DO - 10.1080/10962247.2013.755413 VL - 63 IS - 1 SP - 1-1 SN - 1096-2247 ER - TY - JOUR TI - Megacity impacts on regional ozone formation: observations and WRF-Chem modeling for the MIRAGE-Shanghai field campaign AU - Tie, X. AU - Geng, F. AU - Guenther, A. AU - Cao, J. AU - Greenberg, J. AU - Zhang, R. AU - Apel, E. AU - Li, G. AU - Weinheimer, A. AU - Chen, J. AU - Cai, C. T2 - Atmospheric Chemistry and Physics DA - 2013/// PY - 2013/// VL - 13 IS - 11 SP - 5655-5669 ER - TY - JOUR TI - Kinematic and Thermodynamic Structures of Sierra Barrier Jets and Overrunning Atmospheric Rivers during a Landfalling Winter Storm in Northern California AU - Kingsmill, David E. AU - Neiman, Paul J. AU - Moore, Benjamin J. AU - Hughes, Mimi AU - Yuter, Sandra E. AU - Ralph, F. Martin T2 - MONTHLY WEATHER REVIEW AB - Abstract This study characterizes kinematic and thermodynamic structures of Sierra barrier jets (SBJs), atmospheric rivers (ARs), and their interaction over the period 14–16 February 2011 when a winter storm made landfall in northern California. A suite of scanning and profiling Doppler radars, rawinsondes, and GPS receivers is used to document these structures across the Central Valley and up the western Sierra slope to the crest along an ~200-km segment of the Sierra. The winter storm is grouped into two episodes, each having an AR that made landfall. Low-level winds in the SBJ observed during episode 1 were southeasterly and embedded in a stably stratified air mass. Along-barrier wind speeds U 340 reached maximum values of 25–30 m s −1 , as low as ~0.2 km MSL over the Central Valley, and as high as ~1.5 km MSL over the western Sierra slope. Southwesterly winds associated with the AR overlaid the SBJ along an interface that sloped upward from southwest to northeast with a southwestern extent at the western edge of the Central Valley. In contrast, low-level winds in the SBJ observed during episode 2 were more southerly and embedded in a less stable air mass. The U 340 reached maximum values that were slightly weaker (~20–25 m s −1 ) and spread over a thicker layer that extended to higher levels over the western Sierra (~2.5 km MSL). Southwesterly winds associated with the AR overlaying the SBJ tilted upward from southwest to northeast with a steeper slope but did not extend as far southwest. DA - 2013/6// PY - 2013/6// DO - 10.1175/mwr-d-12-00277.1 VL - 141 IS - 6 SP - 2015-2036 SN - 0027-0644 ER - TY - JOUR TI - HIRS channel 12 brightness temperature dataset and its correlations with major climate indices AU - Shi, L. AU - Schreck, C. J., III AU - John, V. O. T2 - ATMOSPHERIC CHEMISTRY AND PHYSICS AB - Abstract. A new version of the High-Resolution Infrared Radiation Sounder (HIRS) upper tropospheric water vapor channel (channel 12) brightness temperature dataset is developed using intersatellite calibrated data. In this dataset, only those pixels affected by upper tropospheric clouds are discarded. Compared to the previous version that was based on column-clear-sky data, the new version has much better daily spatial coverage. The HIRS observation patterns are compared to microwave sounder measurements. The differences between the two types of sounders vary with respect to brightness temperature with larger differences for higher (dry) values. Correlations between the HIRS upper tropospheric water vapor channel brightness temperatures and several major climate indices show strong signals during cold seasons. The selected climate indices track climate variation signals covering regions from the tropics to the poles. Qualitatively, moist signals are correlated with troughs and ascending branches of the circulation, while dry signals occur with ridges and descent. These correlations show the potential of using the upper tropospheric water vapor channel brightness temperature dataset together with a suite of many atmospheric variables to monitor regional climate changes and locate global teleconnection patterns. DA - 2013/// PY - 2013/// DO - 10.5194/acp-13-6907-2013 VL - 13 IS - 14 SP - 6907-6920 SN - 1680-7316 ER - TY - JOUR TI - Dryline Position Errors in Experimental Convection-Allowing NSSL-WRF Model Forecasts and the Operational NAM AU - Coffer, Brice E. AU - Maudlin, Lindsay C. AU - Veals, Peter G. AU - Clark, Adam J. T2 - WEATHER AND FORECASTING AB - Abstract This study evaluates 24-h forecasts of dryline position from an experimental 4-km grid-spacing version of the Weather Research and Forecasting Model (WRF) run daily at the National Severe Storms Laboratory (NSSL), as well as the 12-km grid-spacing North America Mesoscale Model (NAM) run operationally by the Environmental Modeling Center of NCEP. For both models, 0000 UTC initializations are examined, and for verification 0000 UTC Rapid Update Cycle (RUC) analyses are used. For the period 1 April–30 June 2007–11, 116 cases containing drylines in all three datasets were identified using a manual procedure that considered specific humidity gradient magnitude, temperature, and 10-m wind. For the 24-h NAM forecasts, no systematic east–west dryline placement errors were found, and the majority of the east–west errors fell within the range ±0.5° longitude. The lack of a systematic bias was generally present across all subgroups of cases categorized according to month, weather pattern, and year. In contrast, a systematic eastward bias was found in 24-h NSSL-WRF forecasts, which was consistent across all subgroups of cases. The eastward biases seemed to be largest for the subgroups that favored “active” drylines (i.e., those associated with a progressive synoptic-scale weather system) as opposed to “quiescent” drylines that tend to be present with weaker tropospheric flow and have eastward movement dominated by vertical mixing processes in the boundary layer. DA - 2013/6// PY - 2013/6// DO - 10.1175/waf-d-12-00092.1 VL - 28 IS - 3 SP - 746-761 SN - 0882-8156 KW - Drylines KW - Cloud resolving models KW - Mesoscale models KW - Model comparison KW - Model errors KW - Model evaluation KW - performance ER - TY - JOUR TI - Discovery of extreme events-related communities in contrasting groups of physical system networks AU - Chen, Zhengzhang AU - Hendrix, William AU - Guan, Hang AU - Tetteh, Isaac K. AU - Choudhary, Alok AU - Semazzi, Fredrick AU - Samatova, Nagiza F. T2 - DATA MINING AND KNOWLEDGE DISCOVERY AB - The latent behavior of a physical system that can exhibit extreme events such as hurricanes or rainfalls, is complex. Recently, a very promising means for studying complex systems has emerged through the concept of complex networks. Networks representing relationships between individual objects usually exhibit community dynamics. Conventional community detection methods mainly focus on either mining frequent subgraphs in a network or detecting stable communities in time-varying networks. In this paper, we formulate a novel problem—detection of predictive and phase-biased communities in contrasting groups of networks, and propose an efficient and effective machine learning solution for finding such anomalous communities. We build different groups of networks corresponding to different system’s phases, such as higher or low hurricane activity, discover phase-related system components as seeds to help bound the search space of community generation in each network, and use the proposed contrast-based technique to identify the changing communities across different groups. The detected anomalous communities are hypothesized (1) to play an important role in defining the target system’s state(s) and (2) to improve the predictive skill of the system’s states when used collectively in the ensemble of predictive models. When tested on the two important extreme event problems—identification of tropical cyclone-related and of African Sahel rainfall-related climate indices—our algorithm demonstrated the superior performance in terms of various skill and robustness metrics, including 8–16 % accuracy increase, as well as physical interpretability of detected communities. The experimental results also show the efficiency of our algorithm on synthetic datasets. DA - 2013/9// PY - 2013/9// DO - 10.1007/s10618-012-0289-3 VL - 27 IS - 2 SP - 225-258 SN - 1573-756X KW - Spatio-temporal data mining KW - Complex network analysis KW - Community detection KW - Comparative analysis KW - Networkmotif detection KW - Extreme event prediction ER - TY - JOUR TI - Base-State Substitution: An Idealized Modeling Technique for Approximating Environmental Variability AU - Letkewicz, Casey E. AU - French, Adam J. AU - Parker, Matthew D. T2 - MONTHLY WEATHER REVIEW AB - Abstract Base-state substitution (BSS) is a novel modeling technique for approximating environmental heterogeneity in idealized simulations. After a certain amount of model run time, base-state substitution replaces the original horizontally homogeneous background environment with a new horizontally homogeneous environment while maintaining any perturbations that have developed during the preceding simulation. This allows the user to independently modify the kinematic or thermodynamic environments, or replace the entire sounding without altering the structure of the perturbation fields. Such an approach can provide a powerful hypothesis test, for example, in a study of how an isolated convective storm would respond to a different environment within a horizontally homogeneous setting. The BSS modifications can be made gradually or instantaneously, depending on the needs of the user. In this paper both the gradual and instantaneous BSS procedures are demonstrated for simulations of deep moist convection, using first a wholly idealized setup and then a pair of observed near-storm soundings. Examination of domainwide model statistics demonstrates that model stability is maintained following the introduction of the new background environment. Following BSS, domain total mass and energy exhibit the expected instantaneous jumps upward or downward as a result of the imposed changes to the mean thermal and wind profiles, after which they remain steady during the subsequent simulation. The gridded model fields are well behaved and change gradually as the simulated storms respond meteorologically to their new environments. The paper concludes with a discussion of several unique aspects of the BSS approach. DA - 2013/9// PY - 2013/9// DO - 10.1175/mwr-d-12-00200.1 VL - 141 IS - 9 SP - 3062-3086 SN - 1520-0493 KW - Convective storms KW - Mesoscale systems KW - Storm environments KW - Mesoscale models KW - Numerical analysis KW - modeling ER - TY - JOUR TI - Application of WRF/Chem-MADRID and WRF/Polyphemus in Europe - Part 2: Evaluation of chemical concentrations and sensitivity simulations AU - Zhang, Y. AU - Sartelet, K. AU - Zhu, S. AU - Wang, W. AU - Wu, S. -Y. AU - Zhang, X. AU - Wang, K. AU - Tran, P. AU - Seigneur, C. AU - Wang, Z. -F. T2 - ATMOSPHERIC CHEMISTRY AND PHYSICS AB - Abstract. An offline-coupled model (WRF/Polyphemus) and an online-coupled model (WRF/Chem-MADRID) are applied to simulate air quality in July 2001 at horizontal grid resolutions of 0.5° and 0.125° over Western Europe. The model performance is evaluated against available surface and satellite observations. The two models simulate different concentrations in terms of domainwide performance statistics, spatial distribution, temporal variations, and column abundance. WRF/Chem-MADRID at 0.5° gives higher values than WRF/Polyphemus for the domainwide mean and over polluted regions in Central and southern Europe for all surface concentrations and column variables except for the tropospheric ozone residual (TOR). Compared with observations, WRF/Polyphemus gives better statistical performance for daily HNO3, SO2, and NO2 at the European Monitoring and Evaluation Programme (EMEP) sites, maximum 1 h O3 at the AirBase sites, PM2.5 at the AirBase sites, maximum 8 h O3 and PM10 composition at all sites, column abundance of CO, NO2, TOR, and aerosol optical depth (AOD), whereas WRF/Chem-MADRID gives better statistical performance for NH3, hourly SO2, NO2, and O3 at the AirBase and BDQA (Base de données de la qualité de l'air) sites, maximum 1 h O3 at the BDQA and EMEP sites, and PM10 at all sites. WRF/Chem-MADRID generally reproduces well the observed high hourly concentrations of SO2 and NO2 at most sites except for extremely high episodes at a few sites, and WRF/Polyphemus performs well for hourly SO2 concentrations at most rural or background sites where pollutant levels are relatively low, but it underpredicts the observed hourly NO2 concentrations at most sites. Both models generally capture well the daytime maximum 8 h O3 concentrations and diurnal variations of O3 with more accurate peak daytime and minimal nighttime values by WRF/Chem-MADRID, but neither model reproduces extremely low nighttime O3 concentrations at several urban and suburban sites due to underpredictions of NOx and thus insufficient titration of O3 at night. WRF/Polyphemus gives more accurate concentrations of PM2.5, and WRF/Chem-MADRID reproduces better the observations of PM10 concentrations at all sites. The differences between model predictions and observations are mostly caused by inaccurate representations of emissions of gaseous precursors and primary PM species, as well as biases in the meteorological predictions. The differences in model predictions are caused by differences in the heights of the first model layers and thickness of each layer that affect vertical distributions of emissions, model treatments such as dry/wet deposition, heterogeneous chemistry, and aerosol and cloud, as well as model inputs such as emissions of soil dust and sea salt and chemical boundary conditions of CO and O3 used in both models. WRF/Chem-MADRID shows a higher sensitivity to grid resolution than WRF/Polyphemus at all sites. For both models, the use of a finer grid resolution generally leads to an overall better statistical performance for most variables, with greater spatial details and an overall better agreement in temporal variations and magnitudes at most sites. The use of online biogenic volatile organic compound (BVOC) emissions gives better statistical performance for hourly and maximum 8 h O3 and PM2.5 and generally better agreement with their observed temporal variations at most sites. Because it is an online model, WRF/Chem-MADRID offers the advantage of accounting for various feedbacks between meteorology and chemical species. However, this model comparison suggests that atmospheric pollutant concentrations are most sensitive in state-of-the-science air quality models to vertical structure, inputs, and parameterizations for dry/wet removal of gases and particles in the model. DA - 2013/// PY - 2013/// DO - 10.5194/acp-13-6845-2013 VL - 13 IS - 14 SP - 6845-6875 SN - 1680-7324 ER - TY - JOUR TI - Application of WRF/Chem-MADRID and WRF/Polyphemus in Europe - Part 1: Model description, evaluation of meteorological predictions, and aerosol-meteorology interactions AU - Zhang, Y. AU - Sartelet, K. AU - Wu, S. Y. AU - Seigneur, C. T2 - Atmospheric Chemistry and Physics DA - 2013/// PY - 2013/// VL - 13 IS - 14 SP - 6807-6843 ER - TY - JOUR TI - Accurate Determination of Aerosol Activity Coefficients at Relative Humidities up to 99% Using the Hygroscopicity Tandem Differential Mobility Analyzer Technique AU - Suda, Sarah R. AU - Petters, Markus D. T2 - AEROSOL SCIENCE AND TECHNOLOGY AB - Aerosol water content plays an important role in aqueous phase reactions, in controlling visibility, and in cloud formation processes. One way to quantify aerosol water content is to measure hygroscopic growth using the hygroscopicity tandem differential mobility analyzer (HTDMA) technique. However, the HTDMA technique becomes less reliable at relative humidity (RH) >90% due to the difficulty of controlling temperature and RH inside the second DMA. For this study, we have designed and implemented a new HTDMA system with improved temperature and RH control. Temperature stability in the second DMA was achieved to ±0.02°C tolerance by implementing active control using thermoelectric heat exchangers and PID control loops. The DMA size resolution was increased by operating high-flow DMA columns at a sheath:sample flow ratio of 15:0.5. This improved size resolution allowed for improving the accuracy of the RH sensors by interspersing ammonium sulfate reference scans at high frequency. We present growth factor data for pure compounds at RH up to 99% and compare the data to theoretical values and to available bulk water activity data. With this HTDMA instrument and method, the osmotic coefficients of spherical, nonvolatile aerosols of known composition between 30 and 200 nm in diameter can be determined within ±20%. We expect that data from this instrument will lead to an improvement of aerosol water content models by contributing to the understanding of aerosol water uptake at high RH. Copyright 2013 American Association for Aerosol Research DA - 2013/9/1/ PY - 2013/9/1/ DO - 10.1080/02786826.2013.807906 VL - 47 IS - 9 SP - 991-1000 SN - 1521-7388 ER - TY - JOUR TI - SHORT- VERSUS LONG-TERM RESPONSES TO CHANGING CO2 IN A COASTAL DINOFLAGELLATE BLOOM: IMPLICATIONS FOR INTERSPECIFIC COMPETITIVE INTERACTIONS AND COMMUNITY STRUCTURE AU - Tatters, Avery O. AU - Schnetzer, Astrid AU - Fu, Feixue AU - Lie, Alle Y. A. AU - Caron, David A. AU - Hutchins, David A. T2 - EVOLUTION AB - Increasing pCO2 (partial pressure of CO2 ) in an "acidified" ocean will affect phytoplankton community structure, but manipulation experiments with assemblages briefly acclimated to simulated future conditions may not accurately predict the long-term evolutionary shifts that could affect inter-specific competitive success. We assessed community structure changes in a natural mixed dinoflagellate bloom incubated at three pCO2 levels (230, 433, and 765 ppm) in a short-term experiment (2 weeks). The four dominant species were then isolated from each treatment into clonal cultures, and maintained at all three pCO2 levels for approximately 1 year. Periodically (4, 8, and 12 months), these pCO2 -conditioned clones were recombined into artificial communities, and allowed to compete at their conditioning pCO2 level or at higher and lower levels. The dominant species in these artificial communities of CO2 -conditioned clones differed from those in the original short-term experiment, but individual species relative abundance trends across pCO2 treatments were often similar. Specific growth rates showed no strong evidence for fitness increases attributable to conditioning pCO2 level. Although pCO2 significantly structured our experimental communities, conditioning time and biotic interactions like mixotrophy also had major roles in determining competitive outcomes. New methods of carrying out extended mixed species experiments are needed to accurately predict future long-term phytoplankton community responses to changing pCO2 . DA - 2013/7// PY - 2013/7// DO - 10.1111/evo.12029 VL - 67 IS - 7 SP - 1879-1891 SN - 1558-5646 KW - Acclimation KW - artificial community KW - climate change KW - competition KW - dinoflagellate community KW - ocean acidification ER - TY - JOUR TI - Probable maximum precipitation and climate change AU - Kunkel, Kenneth E. AU - Karl, Thomas R. AU - Easterling, David R. AU - Redmond, Kelly AU - Young, John AU - Yin, Xungang AU - Hennon, Paula T2 - GEOPHYSICAL RESEARCH LETTERS AB - Probable maximum precipitation (PMP) is the greatest accumulation of precipitation for a given duration meteorologically possible for an area. Climate change effects on PMP are analyzed, in particular, maximization of moisture and persistent upward motion, using both climate model simulations and conceptual models of relevant meteorological systems. Climate model simulations indicate a substantial future increase in mean and maximum water vapor concentrations. For the RCP8.5 scenario, the changes in maximum values for the continental United States are approximately 20%–30% by 2071–2100. The magnitudes of the maximum water vapor changes follow temperature changes with an approximate Clausius‐Clapeyron relationship. Model‐simulated changes in maximum vertical and horizontal winds are too small to offset water vapor changes. Thus, our conclusion is that the most scientifically sound projection is that PMP values will increase in the future due to higher levels of atmospheric moisture content and consequent higher levels of moisture transport into storms. DA - 2013/4/16/ PY - 2013/4/16/ DO - 10.1002/grl.50334 VL - 40 IS - 7 SP - SN - 1944-8007 ER - TY - JOUR TI - Organochlorine Pollutants in Western Antarctic Peninsula Sediments and Benthic Deposit Feeders AU - Zhang, Lin AU - Dickhut, Rebecca AU - DeMaster, Dave AU - Pohl, Kari AU - Lohmann, Rainer T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Sediments and benthic deposit feeding holothurians were collected near the Palmer Long Term Ecological Research grid during the austral winter of 2008. Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were measured in Western Antarctic Peninsula continental shelf sediments, porewater, and benthic biota. Concentrations and fluxes in sediments decreased sharply away from the tip of the peninsula toward its interior. Sedimentary PCB fluxes were an order of magnitude lower than reported elsewhere, supporting the notion of a pristiner Antarctic environment. Hexa-chlorinated biphenyls dominated (40–100%) the PCB profiles in the sediments, while trichlorinated biphenyl 28 was the most abundant PCB congener in the porewater. PCB and OCP concentrations in holothurians were comparable to concentrations in other low trophic level biota in the Antarctic food web (i.e., krill). The partitioning of PCBs and OCPs between the sediments and porewater can be explained by a dual-mode model, which included both organic carbon and black carbon as partitioning media. Alternatively, a simpler one-parameter prediction assuming coal tar-like organic carbon performed equally well in explaining porewater concentrations The majorities of PCBs (63–94%) in the Western Antarctic Peninsula sediments were bound to black carbon or recalcitrant tar-like organic carbon, thereby lowering porewater concentrations. PCBs and OCPs in the holothurians were in equilibrium with those in the porewater. DA - 2013/6/4/ PY - 2013/6/4/ DO - 10.1021/es303553h VL - 47 IS - 11 SP - 5643-5651 SN - 1520-5851 ER - TY - JOUR TI - Modeling the Impacts of the Large-Scale Atmospheric Environment on Inland Flooding during the Landfall of Hurricane Floyd (1999) AU - Tang, Qianhong AU - Xie, Lian AU - Lackmann, Gary M. AU - Liu, Bin T2 - ADVANCES IN METEOROLOGY AB - The contribution of the large-scale atmospheric environment to precipitation and flooding during Hurricane Floyd was investigated in this study. Through the vortex removal technique in the Weather Research and Forecasting (WRF) model, the vortex associated with Hurricane Floyd (1999) was mostly removed in the model initial conditions and subsequent integration. Results show that the environment-induced precipitation can account for as much as 22% of total precipitation in the innermost model domain covering North Carolina coastal area and 7% in the focused hydrological study area. The high-resolution precipitation data from the WRF model was then used for input in a hydrological model to simulate river runoff. Hydrological simulation results demonstrate that without the tropical systems and their interactions with the large-scale synoptic environment the synoptic environment would only contribute 10% to the total discharge at the Tarboro gauge station. This suggests that Hurricane Floyd and Hurricane Dennis preceding it, along with the interactions between these tropical systems and the large-scale environment, have contributed to the bulk (90%) of the record amount of flood water in the Tar-Pamlico River Basin. DA - 2013/// PY - 2013/// DO - 10.1155/2013/294956 VL - 2013 SP - SN - 1687-9317 ER - TY - JOUR TI - Improving Stable Boundary-Layer Height Estimation Using a Stability-Dependent Critical Bulk Richardson Number AU - Richardson, H. AU - Basu, S. AU - Holtslag, A. A. M. T2 - BOUNDARY-LAYER METEOROLOGY DA - 2013/7// PY - 2013/7// DO - 10.1007/s10546-013-9812-3 VL - 148 IS - 1 SP - 93-109 SN - 0006-8314 KW - Boundary-layer height KW - Large-eddy simulation KW - Low-level jet KW - Resistance laws KW - Stable boundary layer ER - TY - JOUR TI - Fine scale modeling of agricultural air quality over the southeastern United States using two air quality models. Part I. Application and evaluation AU - Zhang, Y. AU - Olsen, K. M. AU - Wang, K. T2 - Aerosol and Air Quality Research DA - 2013/// PY - 2013/// VL - 13 IS - 4 SP - 1231-1252 ER - TY - JOUR TI - Evolution of sedimentary environments of the middle Jiangsu coast, South Yellow Sea since late MIS 3 AU - Xia, Fei AU - Zhang, Yongzhan AU - Wang, Qiang AU - Yin, Yong AU - Wegmann, Karl W. AU - Liu, J. Paul T2 - Journal of Geographical Sciences DA - 2013/8/9/ PY - 2013/8/9/ DO - 10.1007/s11442-013-1051-5 VL - 23 IS - 5 SP - 883-914 J2 - J. Geogr. Sci. LA - en OP - SN - 1009-637X 1861-9568 UR - http://dx.doi.org/10.1007/S11442-013-1051-5 DB - Crossref KW - Marine Isotope Stage 3 (MIS 3) KW - South Yellow Sea KW - middle Jiangsu coast KW - tidal sand ridge KW - tidal channel KW - sedimentary environment KW - radiocarbon dating KW - seismic stratigraphy KW - sequence stratigraphy ER - TY - JOUR TI - Comment on "Why do tornados and hailstorms rest on weekends?" by D. Rosenfeld and T. Bell AU - Yuter, Sandra E. AU - Miller, Matthew A. AU - Parker, Matthew D. AU - Markowski, Paul M. AU - Richardson, Yvette AU - Brooks, Harold AU - Straka, Jerry M. T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - [1] The paper “Why do tornados and hailstorms rest on weekends?” [Rosenfeld and Bell, 2011] (hereinafter RB2011) contains key misunderstandings of US spring and summer tornadoes, supercell storms, and their environments. In this comment, we show that (1) there is not a robust weekly cycle or midweek maximum in tornado occurrence or tornado days, (2) RB2011's physical explanation for how increased aerosol concentrations would cause increased frequency and severity of tornadoes and hail in supercells is inconsistent with actual supercell storm structures and their environments, and (3) RB2011's method of averaging aerosol and tornado data from 100°W eastward conflates an aerosol weekly cycle in one geographic location with tornado occurrence in another. [2] What are the characteristics of a robust weekly anthropogenic effect? As Vermeesch [2009] points out, the null hypothesis for a weekly cycle in phenomenon X is mathematically equivalent to saying phenomenon X occurs with exactly equal frequency on each day of the week. For data sets of intermittent phenomena, such as tornadoes or earthquakes, such perfect uniformity is highly unlikely. Furthermore, tornados do not occur independently of each other. The synoptic-scale atmospheric environment can favor the formation of groups of storms each producing multiple tornados over their lifetimes [Verbout et al., 2006]. Counts of tornadoes by day of the week over a multiyear period are prone to becoming nonuniform due to a few individual, highly prolific tornado events. Vermeesch [2009] found a statistically significant weekly cycle for earthquake occurrence that peaks on Sundays illustrating that statistical significance in itself is not sufficient to warrant the pronouncement of a weekly anthropogenic effect. Additional necessary conditions for a robust weekly anthropogenic effect include reproducibility with independent data sets, examination of potential sensitivities and biases, and a solid physical basis for causation between correlated weekly cycles [Daniel et al., 2012]. [3] As part of making their case for the causation of a weekly cycle in tornadoes by aerosols, RB2011 have to explain why they found no weekly cycle in tornadoes during April and May. According to RB2011, dew points ≥15°C are necessary in order to have sufficiently warm cloud bases for aerosol effects to occur (RB2011, para. 12). RB2011 explain the lack of a weekly tornado cycle during April and May (their Figure 7b, their paragraph 48) as being “consistent with the diminution of the convective invigoration effect in cool base clouds.” RB2011 mischaracterize storm environments by using monthly mean dew points ≥15°C as the criterion to exclude April and May storms east of 100°W from their analysis. Instead, an examination of tornado environments on a case-by-case basis is needed in order to justify the exclusion of April and May tornadoes from their study. [4] We examine the validity of RB2011's exclusion of the April and May tornadoes using the severe weather data set developed by Smith et al. [2012] for the CONUS region over the years 2003–2011. Smith et al.'s data set contains the strongest tornado that is reported each hour within each 40 km × 40 km analysis grid box of the Rapid Update Cycle (RUC) model [Benjamin et al., 2004]. Meteorological variables from the corresponding time and RUC 40 km × 40 km grid box are used to describe the environmental characteristics of each tornado. We filter the data set to retain only tornadoes produced by supercells that occurred during April–August and in locations east of 100°W. These filters yield a sample of 4490 tornadoes—2791 in March and April and 1699 in June, July, and August—that we will call the “tornado cases.” [5] Ninety percent of the tornado cases in April and May have dew points ≥15°C that fit the RB2011 criterion for warm-based clouds, and 27% have dew points ≥ 20°C (Figures 1 and 2). In each year examined, there are more tornado cases with dew points ≥15°C in the two months of April and May than in the three months of June through August combined. Following the logic of RB2011, exclusion of the vast majority of April and May tornado cases which have surface dew points ≥15°C would be unwarranted. [6] In this section, we use the same Storm Prediction Center (SPC) tornado report database (http://www.spc.noaa.gov/wcm#data) as RB2011 for the region east of 100°W, except that we look at a longer stretch of years and treat tornadoes that cross state boundaries as one tornado rather than as separate tornadoes as RB2011 did. From 2000 to 2011, there are 15,701 tornadoes in the database. Of those tornadoes, 169 of them cross state lines, and three of those traverse three states. So, ≈1% of the tornadoes in the database cross state lines. We also distinguish between all tornadoes of intensity F0 and greater (F0+) and F1 and greater (F1+). This distinction is made since F1+ tornadoes are more consistently reported than F0s [Doswell et al., 2009]. RB 2011 use the period 1980–2009 to determine the average number of tornadoes per day of year and use the post-WSR-88D period from 1995–2009 for their weekly cycle analysis. They do not discuss either reproducibility for independent data sets nor the sensitivity of their results to tornado intensity. [7] Table 1 shows the tornado counts and tornado days east of 100°W by day of the week for 1995–2009, 1980–1994, and 1965–1979 for different sets of months and ranges of tornado intensity. There are many more F0s than F1s—typically 30–70% depending on the period examined—since frequency of tornadoes falls off as the intensity increases [Brooks and Doswell, 2001]. We reproduce RB2011's Wednesday peak for JJA and F0+ from 1995 to 2009. We do not reproduce their minimum of Saturday and instead have minimum on Sunday. This minor discrepancy is not significant and likely a result of a combination of our use of an updated version of the SPC database (RB2011's access was prior to August 2011 while we downloaded the data in July 2012) and RB2011's use of 3 day running average to smooth the data. Once one looks outside of RB2011's selected temporal subset of SPC data, the lack of a robust weekly cycle in tornado counts is clear (Table 1 and Figure 3). [8] The days of the week for which the maximum and minimum in tornado counts occur are sensitive to tornado intensity (Table 1 and Figure 3). Use of the more consistently reported F1+ tornadoes during JJA for 1995–2009, i.e., just the removal of the F0 tornadoes, shifts the weekday tornado count maximum to Thursday. For 1980–1994 F0+ in JJA, the tornado maximum is Tuesday, and the minimum is Friday, while for F1+, it is Monday and Friday, respectively. Including tornadoes that occurred during May more than doubles the sample size with very little contamination from tornadoes not fitting RB2011's 15 °C warm cloud base criterion (Figures 1 and 2). For these data, the maximum in tornado counts for 1995–2009 jumps from Sunday for F0+ to Thursday for F1+. Additionally, tornadoes for MJJA in 1995–2009 with intensity of F0+ have maximum and minimum tornado counts on consecutive days (Sunday and Monday). Going further back into the record for the period 1965–1979, the maximum and minimum for F0+ during MJJA are on consecutive days (Thursday and Friday) as well. The occurrence of maximum and minimum tornado counts on consecutive days is incompatible with the sinusoidal weekly pattern to which RB2011 fit their data (their section 3.2). [9] The use of raw tornado counts can also be problematic because a few days have large outbreaks of tornadoes whereas many days have no tornadoes. Examination of the number of days on which any tornado occurred east of 100°W (Table 2) shows a lower amplitude cycle regardless of the time period examined. The data in Tables 1 and 2 are incongruous with a robust weekly cycle whether one uses tornado reports prior to the 1995 implementation of the WSR-88D radar network or not. [10] Most tornadoes are produced by supercell thunderstorms (Figure 4), including almost all EF2 and greater tornadoes [Smith et al., 2012]. RB2011's hypothesized aerosol influences upon tornadoes rely upon an overly simplified view of supercell formation, structure, and storm-scale processes. [11] Large vertical wind shear is fundamental to supercell formation because supercell updrafts derive their midlevel vertical vorticity via tilting of environmental horizontal vorticity, and because they derive their longevity from both the separation of precipitation from the parent updraft and from the dynamical enhancement of upward accelerations attributable to the presence of vertical wind shear (see the reviews by Klemp [1987], Rotunno [1993], and Davies-Jones et al. [2001]). These effects of vertical wind shear in turn contribute to the 3D character of supercells' precipitation, wind, and temperature fields, which are distinctly different from those of ordinary thunderstorms. Although RB2011 do not appear to consider the 3D complexity of supercells, they do acknowledge the importance of vertical wind shear (their paragraph 9), and for this reason, they discount “aerosol-induced invigoration of the updraft” as a valid effect in supercells, citing the modeling study of Fan et al. [2009]. Instead, RB2011 propose that “aerosol-induced changes in the precipitation particle size distribution reduce the evaporative cooling in the precipitation shaft” (their paragraph 9) and then connect this to previous observations that significantly tornadic supercells tend to have less negative buoyancy in their rear-flank outflows [Markowski et al., 2002; Grzych et al., 2007; Hirth et al., 2008]. [12] The connection of aerosols to outflow temperature, as envisioned by RB2011, proceeds as follows. “Because the effect of aerosols is to suppress coalescence, rain is delayed and a larger fraction of the cloud water ascends above the 0 °C isotherm level…” (their paragraph 5), which in turn would be expected to enhance riming aloft (their paragraphs 5 and 7). RB2011 explain that the net effects of this change would then increase the total latent heat release aloft (their paragraph 5), which could invigorate the updraft (although RB2011 discount the importance of this effect for supercells, as noted above). RB2011 also surmise that larger hailstones should result; presumably, they believe this is due to the enhanced amount of supercooled liquid water aloft, since RB2011 stipulate that the updraft invigoration effect is thought to be negligible for supercells. The end result envisioned by RB2011 is that the aerosol-enhanced clouds have fewer and larger raindrops (their paragraph 11), which would lessen the potential for evaporative cooling and thus yield weaker (warmer) outflow from the storm. [13] We question whether RB2011's chain of aerosol influences is applicable to supercells on the basis that there is little time for droplet growth below the 0°C level within supercell updrafts as-is, and that the distribution of precipitation particles and formation pathways varies markedly from sector to sector within supercell storms, making the aerosol linkage to outflow temperature near the tornado indirect at best. Most rain in supercells is a result of melting and shedding [e.g., Rasmussen and Heymsfield, 1987], with or without an overabundance of aerosols, and the presence of rain is highly dependent on the variable trajectories that larger ice hydrometeors take in these storms [Knight and Knight, 2001]. Tornadogenesis simulations conducted by Lerach et al. [2008] and Lerach and Cotton [2012] suggest that while aerosols can have a small impact on tornadogenesis where everything else is equal, other factors, such as cold pool dynamics, have a much greater influence. [14] A recurring radar signature of supercells, most prominent at midlevels, is a relative minimum in reflectivity colocated with the updraft, surrounded by an annulus of higher reflectivity. This so-called bounded weak echo region (BWER) is where updraft velocities are sufficiently strong to inhibit both precipitation formation and precipitation fallout (Figures 4b and 4c). Significantly, BWERs usually extend well above the 0°C level (note the location of the freezing level in Figure 4c). The fact that supercell updrafts usually have BWERs is an important point, because BWERs illustrate that droplets do not have much time to grow via collision-coalescence below the 0°C level in most supercell updrafts. The conditions needed to obtain large supercooled liquid water content and enhanced riming aloft are actually routinely present in supercells, without the need to invoke any aerosol influences. [15] We have already noted in section 3.1 that the aerosol impacts on warm rain that RB2011 describe should be muted within supercell updrafts. In addition, their argument regarding hailstone size employs an overly simplified understanding of bulk hail population, as they ignore the wide variety of hailstone trajectories in supercells, the diversity of which is primarily due to differential size sorting [Knight and Knight, 2001]. Model simulations of hailstorms have suggested that the impacts on hail from aerosols are complex and hard to predict. Simulations by Khain et al. [2011] demonstrated an increase in hail mass and hail diameter when cloud condensation nuclei (CCN) concentration changed from 100 to 3000 cm−3. Simulations by Noppel et al. [2010] covaried both CCN concentration (from 100 to 2100 cm−3) and cloud droplet size distributions. They found differing relationships among increasing CCN concentration, hail mass, and the number concentration of large hail stones depending on the shape of the cloud drop size distribution (their Tables 3 and 4). They concluded that “the complexity of a hailstorm – the manifold microphysical processes that interact with each other as well as the dynamics of the storm – make it difficult, if not impossible, to predict what will happen if one microphysical parameter like CCN is changed.” [16] RB2011 hypothesizes that the increase in supercooled water due to aerosol-laden updrafts leads to the growth of larger hail. Only hailstones that follow favorable trajectories through sufficient supercooled liquid water will become large, and then only if the hail particle has a high collection efficiency for the supercooled droplets. The first aerosol indirect effect is that increased aerosol concentrations lead to increased cloud droplet numbers and result in smaller cloud droplets for a given vapor mass flux through a cloud [Twomey, 1974]. Theory and experimental data for hailstone embryo growth [Cober and List, 1993] and hailstone growth [Greenan and List, 1995] show that smaller cloud droplets result in significantly smaller collection efficiencies, making it more difficult for hailstones to grow. These collection efficiencies approach zero for cloud droplets that are too small (Stokes parameter <1, see Cober and List's Figure 10 and Greenan and List's Figure 14, which show collection efficiencies for hail embryos and hailstones, respectively). The end result is that smaller (not larger) hailstones could result from increased aerosol number concentrations, which would short-circuit RB2011's mechanism. [17] In addition, we are skeptical that RB2011's purported aerosol influence on precipitation and the resulting outflow temperature, even if it were sound, could be uniformly applied across the 3D structure of a supercell thunderstorm. The classic Lemon and Doswell [1979] conceptual model of a supercell (Figure 4a) simplifies a more complex structure. The forward-flank outflow may often be quite weak [e.g., Shabbott and Markowski, 2006; Frame et al., 2009], and the rear-flank outflow is apparently quite variable in both temperature and winds [e.g., Beck et al., 2006; Grzych et al., 2007; Marquis et al., 2008, 2012; Lee et al., 2012]. In addition, regardless of the aerosol concentration of the environment, the precipitation in a supercell already contains different populations of drops and ice particles in different parts of the storm [e.g., Romine et al., 2008; Kumjian and Ryzhkov, 2008, 2012; Van Den Broeke et al., 2008; Kumjian, 2011]: dual-polarization radar data suggest that at low altitudes, the forward flank largely comprises sparse large drops, the main downdraft largely comprises hail and meltwater shed from hail, and the hook echo is complicated with different mean drop sizes in different parts of the hook area Frame et al. [2009]. [18] Tornadogenesis (or tornadogenesis failure) appears to be closely related to outflow temperatures in the vicinity of the hook echo and within the near-surface mesocyclone [e.g., Markowski et al., 2002, 2003]. The precipitation size distribution in that part of the storm is temporally unsteady and results from a number of competing processes including horizontal advection by the storm's 3D wind field (as reviewed by Markowski [2002]), size sorting [e.g., Kumjian and Ryzhkov, 2008, 2012; Van Den Broeke et al., 2008; Kumjian, 2011], and small-scale episodic descent of pockets of precipitation particles from aloft (i.e., “descending reflectivity cores”) [Rasmussen et al., 2006; Byko et al., 2009]. Indeed, Kumjian [2011] called the drop size distributions in hook echoes “exotic and atypical of rainfall from other precipitating systems.” RB2011's one-size-fits-all approach attempts to relate aerosol content to a storm's mean precipitation diameter, a quantity that likely has little relevance for outflow temperatures in supercells' rear flanks. [19] RB2011 find a Tuesday peak in the concentration of PM10 and a Wednesday peak in PM2.5 using Environmental Protection Agency monitoring site data. They neglect regional variations in the aerosol cycle by averaging data over all the monitoring sites east of 100°W during JJA of 1998–2005 (RB2011, caption for their Figure 4), when in fact the aerosol cycle is much weaker where tornadoes are most frequent. [20] Previous work indicates that weekly variations in aerosol concentrations across the US are different region to region. The largest magnitude variations between work week highs and weekend lows in the US are associated with urban areas [e.g., Motallebi et al., 2003; DeGaetano and Doherty, 2004; Shutters and Balling, 2006]. Xia et al. [2008] used 1° × 1° satellite observations of aerosol optical depth (MODIS 550 nm AOD) to examine the weekly cycle of AOD worldwide. AOD can be a reasonable proxy for CCN [Andreae, 2009]. For the US region east of 100°W, they found the “work week” (Tues. – Fri.) AOD peaks (often >20% departure from the weekly average) primarily east of the Appalachian Mountains. Weekly cycles in AOD with large amplitudes up to 30% deviation from weekly average were found along the Washington D.C. to Boston corridor and in the Carolinas [Xia et al., 2008, Figure 7]. In contrast, the amplitudes of the weekly cycles of AOD west of the Appalachian Mountains, where most of the JJA tornadoes east of 100°W occur (Figure 3b), are typically ≤10% deviation from weekly average with many observation locations failing to meet a 90% significance threshold. Furthermore, some locations in Wisconsin, Iowa, and Minnesota had a low-amplitude “weekend” (Sat.–Mon.) peak in AOD observations (typically ≤10% deviation from weekly average), opposite that described in RB2011. Bell et al. [2008, Figure 2] showed only cycles in PM2.5 with an amplitude of ≤10% deviation from weekly average for the US region from 90° W to 100° W spanning Minnesota south to the Gulf Coast. By averaging aerosol station data from 100°W eastward, RB2011 have conflated phenomena in different geographic regions: an aerosol cycle that is stronger in the eastern US and tornadoes that occur more frequently in the central US. [21] RB2011's hypothesis that there is causation between a weekly cycle of aerosols and a weekly cycle in tornadoes for the region east of 100°W does not withstand close scrutiny. The SPC tornado report data show that there is no robust weekly cycle in tornado occurrence or in tornado days whether one considers JJA or MJJA. Based on their own analysis, there is no significant weekly cycle in tornadoes east of 100°W during April and May, yet 85% of the April storms and 94% of the May storms have dew points fitting the >≈ 15 °C criteria for warm-based clouds supposedly susceptible to aerosol effects. Last, the weekly cycles of aerosols are usually weak to insignificant in the regions east of 100°W with a high frequency of tornadoes [Bell et al., 2008; Xia et al., 2008]. [22] It is probably not surprising that the purported signals are not robust, because the dynamical and microphysical structures of supercells are inconsistent with RB2011's hypothesized physical basis. Supercell updrafts already have limited growth of drops below the 0°C level (muting any of the purported aerosol influences), and supercell precipitation cascades are heterogeneous. Perhaps, this explains why meteorological parameters such as boundary layer relative humidity and lifting condensation level height have proven to be skillful at discriminating tornadic supercells from nontornadic supercells [Rasmussen and Blanchard, 1998; Markowski et al., 2002; Thompson et al., 2003; Craven and Brooks, 2004] without taking into account the aerosol content or the size distribution of hydrometeors. Such humidity variables have a significant correlation with outflow temperature in supercells [Markowski et al., 2002; Shabbott and Markowski, 2006], as well as a much more direct physical linkage through decreased evaporation in environments with increased relative humidity. [23] Empirical evidence for a cause and effect relationship between higher aerosol concentrations and an increased incidence of tornadoes has yet to be shown. Modeling studies that examine the sensitivity of storms to only perturbations in CCN concentration cannot address the relative role of CCN compared to other plausible sources of storm variability. For example, plausible causal factors for weekly, annual, and decadal trends in summer severe storm frequency over the US include: air temperature and humidity variations associated with large-scale weather systems and persistent sea surface temperature anomalies in the Gulf of Mexico, aerosol direct effects, land surface changes, and changes in large-scale circulations associated with interannual and interseasonal oscillations, to name a few. Until such causal factors can be simultaneously examined in sensitivity studies with techniques like factor separation [Stein and Alpert, 1993], the attribution of any purported effect to one particular cause is premature. [24] This research was supported by the U.S. Department of Energy Atmospheric Systems Research grant DE SC0006701 (Yuter and Miller); the National Aeronautics and Space Administration grant NNX11AE98G (Yuter and Miller); and the National Science Foundation grants ATM-0908420 (Yuter), ATM-0801035 (Markowski, Richardson), AGS-1156123 (Parker), and AGS-1036237 (Straka). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation. DA - 2013/7/16/ PY - 2013/7/16/ DO - 10.1002/jgrd.50526 VL - 118 IS - 13 SP - 7332-7338 SN - 2169-8996 KW - supercell KW - tornado KW - aerosol KW - hail KW - weekly cycle ER - TY - JOUR TI - Coastal evolution of Yancheng, northern Jiangsu, China since the mid-Holocene based on the Landsat MSS imagery AU - Kang, Y. Y. AU - Xia, F. AU - Ding, X. R. AU - Zhang, C. K. AU - Cheng, L. G. AU - Ge, X. P. AU - Glass, J. T2 - Journal of Geographical Sciences DA - 2013/// PY - 2013/// VL - 23 IS - 5 SP - 915-931 ER - TY - JOUR TI - Atmospheric dissolved iron deposition to the global oceans: effects of oxalate-promoted Fe dissolution, photochemical redox cycling, and dust mineralogy AU - Johnson, M. S. AU - Meskhidze, N. T2 - GEOSCIENTIFIC MODEL DEVELOPMENT AB - Abstract. Mineral dust deposition is suggested to be a significant atmospheric supply pathway of bioavailable iron (Fe) to Fe-depleted surface oceans. In this study, mineral dust and dissolved Fe (Fed) deposition rates are predicted for March 2009 to February 2010 using the 3-D chemical transport model GEOS-Chem implemented with a comprehensive dust-Fe dissolution scheme. The model simulates Fed production during the atmospheric transport of mineral dust, taking into account inorganic and organic (oxalate)-promoted Fe dissolution processes, photochemical redox cycling between ferric (Fe(III)) and ferrous (Fe(II)) forms of Fe, dissolution of three different Fe-containing minerals (hematite, goethite, and aluminosilicates), and detailed mineralogy of wind-blown dust from the major desert regions. Our calculations suggest that during the year-long simulation ~0.26 Tg (1 Tg = 1012 g) of Fed was deposited to global oceanic regions. Compared to simulations only taking into account proton-promoted Fe dissolution, the addition of oxalate and Fe(II)/Fe(III) redox cycling to the dust-Fe mobilization scheme increased total annual model-predicted Fed deposition to global oceanic regions by ~75%. The implementation of Fe(II)/Fe(III) photochemical redox cycling in the model also allows for the distinction between different oxidation states of deposited Fed. Our calculations suggest that during the daytime, large fractions of Fed deposited to the global oceans is likely to be in Fe(II) form, while nocturnal fluxes of Fed are largely in Fe(III) form. Model sensitivity simulations suggest Fed fluxes to the oceans can range from ~50% reduction to ~150% increase associated with the uncertainty in Fe-containing minerals commonly found in dust particles. This study indicates that Fed deposition to the oceans is controlled by total dust-Fe mass concentrations, mineralogy, the surface area of dust particles, atmospheric chemical composition, cloud processing, and meteorological parameters and exhibits complex and spatiotemporally variable patterns. Our study suggests that the explicit model representation of individual processes leading to Fed production within mineral dust are needed to improve the understanding of the atmospheric Fe cycle, and quantify the effect of dust-Fe on ocean biological productivity, carbon cycle, and climate. DA - 2013/// PY - 2013/// DO - 10.5194/gmd-6-1137-2013 VL - 6 IS - 4 SP - 1137-1155 SN - 1991-9603 ER - TY - JOUR TI - Surface water geochemistry and chemical weathering across Panama AU - Harmon, Russell S. AU - Lyons, W. Berry AU - Gardner, Christopher B. AU - Goldsmith, Steven T. AU - Long, David T. AU - Mitasova, Helena AU - Welch, Susan AU - Welch, Kathy T2 - PROCEEDINGS OF THE FOURTEENTH INTERNATIONAL SYMPOSIUM ON WATER-ROCK INTERACTION, WRI 14 AB - Abstract A geochemical study of rivers and streams was undertaken across Panama during 2005-09, from the Lago Bayano area in the east to the Costa Rican border in the west. Low overall dissolved solute contents (TDS = 145±160 mg/L) suggest a short residence time for infiltrating precipitation in the weathering zone. Watershed lithology exerts the main control on riverine chemistry, with streams on marine sedimentary rocks having higher dissolved solids loads than those on igneous rocks, with the latter exhibiting the highest silica contents and increasing trends of total cations with increasing dissolved silica. This feature and the large degree of compositional overlap between large rivers and small tributary streams implies that chemical weathering of silicate materials in the soil zone is the predominant process determining the geochemistry of streams and rivers in this tropical environment. Silicate weathering rates (Casil+Mgsil+Na+K) range over more than an order in magnitude from 2.5 to 28.4 tons/km2/y, whilst H4SiO4 yields range from 7.1 to 65 tons/km2/y. Basin-wide CO2 consumption yields by silicate weathering, calculated from total cation content (corrected for sea salt contribution), basin area and discharge, are high on a global basis. DA - 2013/// PY - 2013/// DO - 10.1016/j.proeps.2013.03.134 VL - 7 SP - 342-345 SN - 1878-5220 KW - Panama KW - tropical rivers KW - river chemistry KW - chemical denudation ER - TY - JOUR TI - RELATIONSHIP BETWEEN THE ELLISVILLE PLUTON AND CHOPAWAMSIC FAULT: ESTABLISHMENT OF SIGNIFICANT LATE ORDOVICIAN FAULTING IN THE APPALACHIAN PIEDMONT OF VIRGINIA AU - Hughes, K. Stephen AU - Hibbard, James P. AU - Miller, Brent V. T2 - AMERICAN JOURNAL OF SCIENCE AB - The Chopawamsic fault is the most significant boundary in the western Piedmont of north central Virginia; it separates the metaclastic Early Ordovician or older Potomac terrane of Laurentian affinity from the dominantly metavolcanic Middle to Late Ordovician Chopawamsic terrane of unknown cratonic heritage. On regional maps, the Ellisville pluton had previously been depicted as stitching the Chopawamsic fault, although this relationship has never been documented. It has been hypothesized that the Chopawamsic fault marks the suture of the early Paleozoic Iapetus Ocean, which once separated Laurentian and Gondwanan crustal elements. Consequently, it is important to examine the stitching relationship in detail in order to place timing constraints on motion along this fault. We integrate detailed field mapping, kinematic analysis, petrography, major-oxide, trace, and rare earth element geochemistry, and U-Pb zircon geochronology in order to deduce the relationships between the Ellisville pluton, the Chopawamsic fault, and thus, the Potomac and Chopawamsic terranes in central Virginia. Our study reveals local textural and minor geochronologic variations in the Ellisville pluton, whereas composition and geochemistry are mostly homogenous throughout the body. These data, along with 1:24,000 scale mapping, collectively confirm that the Ellisville pluton stitches the Potomac and Chopawamsic terranes across the Chopawamsic fault. New U-Pb zircon geochronological analyses yield ages of *ca.* 444 Ma and *ca.* 437 Ma, and indicate that the latest significant movement of the fault occurred before a 443.7 ± 3.3 Ma main phase of magmatism present throughout the Ellisville pluton. These dates, with previously determined crystallization ages from the Chopawamsic terrane, constrain significant movement on the Chopawamsic fault to a *ca.* 10 million year interval in the Late Ordovician between *ca.* 453 to 444 Ma. Whether the accretion of the Chopawamsic terrane involved the closing of either a back-arc seaway or a global ocean has yet to be determined; however, based on its timing and kinematic nature, we suggest that the development of the Chopawamsic fault may be related to the Late Ordovician to Early Silurian Cherokee orogeny. DA - 2013/6// PY - 2013/6// DO - 10.2475/06.2013.03 VL - 313 IS - 6 SP - 584-612 SN - 1945-452X KW - Appalachian Piedmont KW - stitching pluton KW - Chopawamsic fault KW - Ellisville pluton ER - TY - JOUR TI - Production mechanisms, number concentration, size distribution, chemical composition, and optical properties of sea spray aerosols AU - Meskhidze, N. AU - Petters, M. D. AU - Tsigaridis, K. AU - Bates, T. AU - O'Dowd, C. AU - Reid, J. AU - Lewis, E. R. AU - Gantt, B. AU - Anguelova, M. D. AU - Bhave, P. V. AU - Bird, J. AU - Callaghan, A. H. AU - Ceburnis, D. AU - Chang, R. AU - Clarke, A. AU - Leeuw, G. AU - Deane, G. AU - DeMott, P. J. T2 - Atmospheric Science Letters DA - 2013/// PY - 2013/// VL - 14 IS - 4 SP - 207-213 ER - TY - JOUR TI - Numerical study of the sensitivity of mangroves in reducing storm surge and flooding to hurricane characteristics in southern Florida AU - Liu, Huiqing AU - Zhang, Keqi AU - Li, Yuepeng AU - Xie, Lian T2 - CONTINENTAL SHELF RESEARCH AB - The sensitivity of the mangrove effect on reducing storm surge flooding to hurricane characteristics is investigated by using the numerical model Coastal and Estuarine Storm Tide (CEST). First, the attenuation of storm surge by mangroves is incorporated into the model by updating Manning’s coefficient based on the National Land Cover Dataset (NLCD) 2001. Then CEST is verified by comparing the model results with field observations in South Florida for Hurricane Wilma. Secondly, a set of numerical experiments using synthetic hurricanes with different intensity, forward speed, radius of maximum wind speed and travel direction are conducted for the sensitivity study. Results indicate that storm surge magnitudes and flooding areas are reduced by the mangrove zone more for fast moving hurricanes than slow moving hurricanes in the west coast of South Florida. In addition, increasing hurricane intensity and hurricane size lower the effect of mangroves on attenuating storm surge and reducing the flooding area. The mangrove zone plays a more effective role in reducing flooding areas from hurricanes that travel from east to west than from hurricanes that travel from west to east. The mangrove reduction effect is most sensitive to changes in hurricane forward speed. A 6.7 m/s to 2.2 m/s decrease in forward speed can result in a decrease in flood area reduction by mangroves that is equivalent to the decrease in flood area reduction by mangroves from Category 3 to 5 hurricanes. DA - 2013/8/1/ PY - 2013/8/1/ DO - 10.1016/j.csr.2013.05.015 VL - 64 SP - 51-65 SN - 0278-4343 KW - Mangroves KW - Storm surge KW - Hurricane KW - Surge attenuation KW - Storm surge modeling ER - TY - JOUR TI - Numerical Study of the Effects of Wave-Induced Forcing on Dynamics in Ocean Mixed Layer AU - Deng, Zengan AU - Xie, Lian AU - Yu, Ting AU - Shi, Suixiang AU - Jin, Jiye AU - Wu, Kejian T2 - ADVANCES IN METEOROLOGY AB - Numerical experiments using hybrid coordinate ocean model (HYCOM) are designed to quantify the effects of wind wave-induced Coriolis-Stokes forcing (CSF) on mixed layer (ML) dynamics in a global context. CSF calculated by the wave parameters simulated by using the WaveWatch III (WW3) model is introduced as a new driving force for HYCOM. The results show that noticeable influence on ocean circulation in ML can be caused by CSF. Over most of the global oceans the direction of Stokes transport is different from that of the change in current transport caused by CSF. This is not unusual because CSF is normal to Stokes drift. However, the CSF-caused change in current transport and the wave-induced Stokes transport have the same magnitude. The seasonal variabilities of mixed layer temperature (MLT) and mixed layer depth (MLD) caused by CSF are analyzed, and the possible relationship between them is also given. DA - 2013/// PY - 2013/// DO - 10.1155/2013/365818 VL - 2013 SP - SN - 1687-9317 ER - TY - JOUR TI - Coastal upwelling linked to toxic Pseudo-nitzschia australis blooms in Los Angeles coastal waters, 20052007 AU - Schnetzer, Astrid AU - Jones, Burton H. AU - Schaffner, Rebecca A. AU - Cetinic, Ivona AU - Fitzpatrick, Elizabeth AU - Miller, Peter E. AU - Seubert, Erica L. AU - Caron, David A. T2 - JOURNAL OF PLANKTON RESEARCH AB - Harmful algal blooms dominated by the diatom Pseudo-nitzschia spp. have become a perennial but variable event within surface waters near the greater Los Angeles area. Toxic blooms during spring seasons from 2005 to 2007 varied strongly in their overall toxicity and duration. Differences in bloom dynamics were linked to differences in storm-induced river discharge following episodic rain events and coastal upwelling, both major coastal processes that led to the injection of nutrients into coastal surface waters. Heavy river runoff during early 2005, a record-rainfall year, favored a phytoplankton community mainly comprised of algal taxa other than Pseudo-nitzschia. The spring bloom during 2005 was associated with low domoic acid surface concentrations and minor contributions of (mainly) P. delicatissima to the diatom assemblage. In contrast, highly toxic P. australis-dominated blooms during spring seasons of 2006 and 2007 were linked to strong upwelling events. River discharge quotas in 2006 and 2007, in contrast to 2005, fell well below annual averages for the region. Surface toxin levels were linked to colder, more saline (i.e. upwelled) water over the 3-year study, but no such consistent relationship between domoic acid levels and other physiochemical parameters, such as macronutrient concentrations or nutrient ratios, was observed. DA - 2013/// PY - 2013/// DO - 10.1093/plankt/fbt051 VL - 35 IS - 5 SP - 1080-1092 SN - 1464-3774 KW - domoic acid KW - Pseudo-nitzschia KW - southern California KW - coastal upwelling KW - river discharge ER - TY - JOUR TI - Ammonia in the atmosphere: a review on emission sources, atmospheric chemistry and deposition on terrestrial bodies AU - Behera, Sailesh N. AU - Sharma, Mukesh AU - Aneja, Viney P. AU - Balasubramanian, Rajasekhar T2 - ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH DA - 2013/11// PY - 2013/11// DO - 10.1007/s11356-013-2051-9 VL - 20 IS - 11 SP - 8092-8131 SN - 1614-7499 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84885897259&partnerID=MN8TOARS KW - Ammonia KW - PM2,(5) KW - Global emissions KW - Atmospheric chemistry KW - Dry deposition KW - Wet deposition ER - TY - JOUR TI - A connection to deep groundwater alters ecosystem carbon fluxes and budgets: Example from a Costa Rican rainforest AU - Genereux, David P. AU - Nagy, Laura A. AU - Osburn, Christopher L. AU - Oberbauer, Steven F. T2 - Geophysical Research Letters AB - Abstract Field studies of watershed carbon fluxes and budgets are critical for understanding the carbon cycle, but the role of deep regional groundwater is poorly known and field examples are lacking. Here we show that discharge of regional groundwater into a lowland Costa Rican rainforest has a major influence on ecosystem carbon fluxes. This influence is observable through chemical, isotopic, and flux signals in groundwater, surface water, and air. Not addressing the influence of regional groundwater in the field measurement program and data analysis would give a misleading impression of the overall carbon source or sink status of the rainforest. In quantifying a carbon budget with the traditional “small watershed” mass balance approach, it would be critical at this site and likely many others to consider watershed inputs or losses associated with exchange between the ecosystem and the deeper hydrogeological system on which it sits. DA - 2013/5/28/ PY - 2013/5/28/ DO - 10.1002/grl.50423 VL - 40 IS - 10 SP - 2066-2070 J2 - Geophys. Res. Lett. LA - en OP - SN - 0094-8276 UR - http://dx.doi.org/10.1002/grl.50423 DB - Crossref KW - rainforest KW - carbon flux KW - groundwater KW - aquifer ER - TY - CONF TI - Using a laser aureole to study aerosols AU - Long, B. J. N. AU - Hook, D. A. AU - Pangle, G. E. AU - Hallen, H. D. AU - Philbrick, C. R. C2 - 2013/// C3 - Laser radar technology and applications xviii DA - 2013/// VL - 8731 ER - TY - JOUR TI - Understanding of the formation mechanisms of ozone and particulate matter at a fine scale over the southeastern US: Process analyses and responses to future-year emissions AU - Liu, Xiao-Huan AU - Zhang, Yang T2 - ATMOSPHERIC ENVIRONMENT AB - Ozone (O3) and fine particle (PM2.5) formation over the southeastern U.S. are of a major concern due to high emissions of precursors and special weather conditions that are conducive to their formation. In this study, the Community Multiscale Air Quality (CMAQ) modeling system is applied to simulate the formation of major air pollutants over an area in the southeastern U.S. at a 4-km horizontal grid resolution for January, April, July, and October in 2002 and 2018. Model performance evaluation shows an overall satisfactory performance for O3 in all months and for PM2.5 in January and October at rural sites and in January, April, and October at urban sites. Large underpredictions in PM2.5 concentrations occur in April and July at rural sites and in July at urban sites, because of biases in meteorological predictions and underestimation of emissions of precursors. The model performance at 4-km in terms of O3, PM2.5 and PM2.5 components show some improvements but overall are not always better than that at 12-km. O3 chemistry is VOC-limited in urban areas and NOx-limited over the west of the mountain regions and the southern Georgia throughout the year, and VOC-limited over the rest of areas in January but NOx-limited in other months. Among all photochemical indicators examined, PH2O2/PHNO3 and O3/NOy are the most robust indicators. The domain is NH3-rich or neutral in all months, indicating a high potential for NH4NO3 formation and the sensitivity of PM2.5 formation to the emissions of SO2, NOx, and NH3. Surface O3 is accumulated primarily through vertical transport in urban, rural and coastal areas and both horizontal and vertical transport in mountain regions and produced via gas-phase chemistry at non-urban sites during daytime. The loss of O3 is attributed to gas-phase chemistry via NO titration in urban areas, and dry deposition and transport processes in rural and mountain areas. PM2.5 is produced by primary emissions and PM processes and lost through vertical and horizontal transport in urban areas. The combined effects of transport, emissions, and PM processes influence PM concentrations in other areas. The 2018 simulations project a decrease in PM2.5 concentrations and an improvement in visibility over almost the entire domain, slight decreases in O3 mixing ratios in urban areas in July and most non-urban areas in April and October but large increases in the rest of areas in other months, and a decrease in total N deposition fluxes in most areas except for central and eastern North Carolina and northern Georgia. The development of integrated emission control strategies should consider region-specific seasonality and differences in the responses of O3, PM2.5, visibility, and nitrogen deposition. DA - 2013/8// PY - 2013/8// DO - 10.1016/j.atmosenv.2013.03.057 VL - 74 SP - 259-276 SN - 1873-2844 KW - CMAQ KW - O-3 KW - PM2.5 KW - Process analysis KW - Chemical regime indicators KW - Future-year air quality ER - TY - CONF TI - Understanding lidar returns from complex dust mixtures AU - Hook, D. A. AU - Pangle, G. E. AU - Long, B. J. N. AU - Philbrick, C. R. AU - Hallen, H. D. C2 - 2013/// C3 - Laser radar technology and applications xviii DA - 2013/// VL - 8731 ER - TY - JOUR TI - The role of time in heterogeneous freezing nucleation AU - Wright, Timothy P. AU - Petters, Markus D. T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - A small fraction of particles in the atmosphere can catalyze ice formation in cloud water drops through heterogeneous freezing nucleation at temperatures warmer than the homogeneous freezing temperature of approximately −38°C. The rate for heterogeneous freezing nucleation is dependent on several factors, including the type and surface area of dust that is immersed inside the drop. Although nucleation is an inherently stochastic process resulting from size fluctuations of the incipient ice germ, there is a growing body of literature that suggests that quasi‐deterministic models of ice nucleation can describe laboratory experiments. Here we present new experiments and simulations that aim to better constrain theoretical models fitted to laboratory data. We collected ice nucleation data for Arizona Test Dust aerosol immersed in water using a droplet freezing assay setup that allows for the cooling rates to be changed between 10 and 0.01 K min −1 . Discrete event simulations based on a variant of the multiple‐component stochastic model of heterogeneous freezing nucleation were used to simulate different experimental procedures. The nucleation properties of the dust are specified by four material‐dependent parameters that accurately describe the time dependence of the freezing process. We anticipate that the combination of discrete event simulations and a spectrum of experimental procedures described here can be used to design more meaningful laboratory experiments probing ice nucleation and will aid the development of better parameterizations for use in models. DA - 2013/5/16/ PY - 2013/5/16/ DO - 10.1002/jgrd.50365 VL - 118 IS - 9 SP - 3731-3743 SN - 2169-8996 KW - Ice nuclei KW - aerosol-cloud interaction KW - immersion mode freezing ER - TY - CONF TI - The role of dynamic surface tension in cloud droplet activation AU - Petters, Markus D. AU - Suda, Sarah R. AU - Christensen, Sara I. T2 - NUCLEATION AND ATMOSPHERIC AEROSOLS: 19th International Conference AB - We present new data on the cloud droplet forming abilities of two-component particles that contain the surfactant sodium dodecyl sulfate and sodium chloride or ammonium sulfate. The experiments were designed to test specific predictions made by Kohler theory that accounts for the reduction of surface tension and the partitioning of the surfactant between the interior and the surface of the droplet. We also introduced a pre-humidification step followed by a six minute time delay to test whether dynamic surface tension may lead to kinetic limitations on the partitioning process. Our results confirm previous studies that show that surfactants do not enhance cloud droplet activation relative to what would be predicted from water activity alone. The data obtained with and without time delay were indistinguishable within measurement uncertainty, suggesting that dynamic surface tension does not need to be considered in Kohler theory. C2 - 2013/// C3 - DA - 2013/// DO - 10.1063/1.4803393 VL - 1527 SP - 801-807 PB - AIP UR - http://dx.doi.org/10.1063/1.4803393 DB - Crossref KW - Cloud condensation nuclei KW - Kohler theory KW - dynamic surface tension ER - TY - JOUR TI - The South-Central US Flood of May 2010: Present and Future AU - Lackmann, Gary M. T2 - JOURNAL OF CLIMATE AB - Abstract Previous studies have documented a feedback mechanism involving the cyclonic low-level jet (LLJ), poleward moisture flux and flux convergence, and condensational heating. Increased water vapor content and potentially heavier precipitation accompanying climate warming suggest the hypothesis that this feedback could strengthen with warming, contributing to amplification of precipitation extremes beyond what the thermodynamically controlled vapor increase would provide. Here, this hypothesis is tested with numerical simulations of a severe flooding event that took place in early May 2010 in the south-central United States. Control simulations with a mesoscale model capture the main features of the May 2010 flooding event. A pseudo–global warming approach is used to modify the current initial, surface, and boundary conditions by applying thermodynamic changes projected by an ensemble of GCMs for the A2 emission scenario. The observed synoptic pattern of the flooding event is replicated but with modified future thermodynamics, allowing isolation of thermodynamic changes on the moisture feedback. This comparison does not indicate a strengthening of the LLJ in the future simulation. Analysis of the lower-tropospheric potential vorticity evolution reveals that the southern portion of the LLJ over the Gulf of Mexico in this event was strengthened through processes involving the terrain of the Mexican Plateau; this aspect is largely insensitive to climate change. Despite the lack of LLJ strengthening, precipitation in the future simulation increased at a super Clausius–Clapeyron rate because of strengthened convective updrafts. DA - 2013/7// PY - 2013/7// DO - 10.1175/jcli-d-12-00392.1 VL - 26 IS - 13 SP - 4688-4709 SN - 1520-0442 KW - Climate change KW - Convective storms KW - Diabatic heating KW - Latent heating KW - cooling KW - Mesoscale processes KW - Orographic effects ER - TY - JOUR TI - The Importance of Resolving Mesoscale Latent Heating in the North Atlantic Storm Track AU - Willison, Jeff AU - Robinson, Walter A. AU - Lackmann, Gary M. T2 - JOURNAL OF THE ATMOSPHERIC SCIENCES AB - Abstract Theoretical, observational, and modeling studies have established an important role for latent heating in midlatitude cyclone development. Models simulate some contribution from condensational heating to cyclogenesis, even with relatively coarse grid spacing (on the order of 100 km). Our goal is to more accurately assess the diabatic contribution to storm-track dynamics and cyclogenesis while bridging the gap between climate modeling and synoptic dynamics. This study uses Weather Research and Forecasting model (WRF) simulations with 120- and 20-km grid spacing to demonstrate the importance of resolving additional mesoscale features that are associated with intense precipitation and latent heat release within extratropical cyclones. Sensitivity to resolution is demonstrated first with a case study, followed by analyses of 10 simulated winters over the North Atlantic storm track. Potential vorticity diagnostics are employed to isolate the influences of latent heating on storm dynamics, and terms in the Lorenz energy cycle are analyzed to determine the resulting influences on the storm track. The authors find that the intensities of individual storms and their aggregate behavior in the storm track are strongly sensitive to horizontal resolution. An enhanced positive feedback between cyclone intensification and latent heat release is seen at higher resolution, resulting in a systematic increase in eddy intensity and a stronger storm track relative to the coarser simulations. These results have implications for general circulation models and their projections of climate change. DA - 2013/7// PY - 2013/7// DO - 10.1175/jas-d-12-0226.1 VL - 70 IS - 7 SP - 2234-2250 SN - 1520-0469 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000322125600022&KeyUID=WOS:000322125600022 KW - Cyclogenesis KW - cyclolysis KW - Extratropical cyclones KW - Potential vorticity ER - TY - CONF TI - Optical extinction dependence on wavelength and size distribution of airborne dust AU - Pangle, G. E. AU - Hook, D. A. AU - Long, B. J. N. AU - Philbrick, C. R. AU - Hallen, H. D. C2 - 2013/// C3 - Laser radar technology and applications xviii DA - 2013/// VL - 8731 ER - TY - JOUR TI - Numerical modeling of a historic storm: Simulating the Blizzard of 1888 AU - Michaelis, Allison C. AU - Lackmann, Gary M. T2 - GEOPHYSICAL RESEARCH LETTERS AB - The National Oceanic and Atmospheric Administration/Cooperative Institute for Research in Environmental Sciences Twentieth Century Reanalysis (20CR) is used to explore the feasibility of high‐resolution simulation of a historic extratropical cyclone event: The New England Blizzard of 1888. Using the 20CR as initial and lateral boundary conditions for the Weather Research and Forecasting model, a reasonable depiction of the cyclone is obtained, albeit displaced significantly to the north of the observed cyclone during the later stages of the event. Despite the position error, the simulated storm produces heavy snowfall over parts of New England and intense offshore cyclogenesis. DA - 2013/8/16/ PY - 2013/8/16/ DO - 10.1002/grl.50750 VL - 40 IS - 15 SP - 4092-4097 SN - 1944-8007 KW - reanalysis KW - extratropical cyclone KW - historical simulation ER - TY - CONF TI - Multistatic lidar measurements of non-spherical aerosols AU - Hallen, H. D. AU - Long, B. J. N. AU - Hook, D. A. AU - Pangle, G. E. AU - Philbrick, C. R. C2 - 2013/// C3 - Laser radar technology and applications xviii DA - 2013/// VL - 8731 ER - TY - JOUR TI - Fossil grebes from the Truckee Formation (Miocene) of Nevada and a new phylogenetic analysis of Podicipediformes (Aves) AU - Ksepka, D. T. AU - Balanoff, A. M. AU - Bell, M. A. AU - Houseman, M. D. T2 - Palaeontology DA - 2013/// PY - 2013/// VL - 56 IS - 5 SP - 1149-1169 ER - TY - JOUR TI - Formation and Growth of Atmospheric Particles at a Forest Site in the Southeast US AU - Pillai, Priya AU - Walker, John AU - Khlystov, Andrey AU - Aneja, Viney T2 - NUCLEATION AND ATMOSPHERIC AEROSOLS AB - Atmospheric particle size distribution measurements (10 ≤ aerodynamic diameter, Dp ≤ 250 nm), which took place above a loblolly pine plantation in the Southeast U.S. from November 2005 to September 2007, were made using Scanning Mobility Particle Sizer (SMPS). The size distributions were investigated to identify new particle formation and to classify the new particle formation episodes into different event classes based on the behavior of particle size distribution and particle growth pattern. About 69% of the observation days had nucleation. The event frequency was highest in spring and lowest in winter. The particle growth rate was highest in May (5.0 ± 3.6 nm hr−1) and lowest in February (1.2 ± 2.2 nm hr−1) with an annual average particle growth rate of 2.5 ± 0.3 nm hr−1. Nucleation frequency and event types are examined along with associated meteorological and chemical conditions. DA - 2013/// PY - 2013/// DO - 10.1063/1.4803288 VL - 1527 SP - 401-404 SN - 0094-243X UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84877358779&partnerID=MN8TOARS KW - Nucleation KW - Particle Size Distribution KW - SMPS KW - Nucleation frequency KW - biogenic VOC KW - Condensation Sink KW - PAR KW - Growth Rate ER - TY - JOUR TI - Dynamic Downscaling of the Impact of Climate Change on the Ocean Circulation in the Galapagos Archipelago AU - Liu, Yanyun AU - Xie, Lian AU - Morrison, John M. AU - Kamykowski, Daniel T2 - ADVANCES IN METEOROLOGY AB - The regional impact of global climate change on the ocean circulation around the Galápagos Archipelago is studied using the Hybrid Coordinate Ocean Model (HYCOM) configured for a four-level nested domain system. The modeling system is validated and calibrated using daily atmospheric forcing derived from the NCEP/NCAR reanalysis dataset from 1951 to 2007. The potential impact of future anthropogenic global warming (AGW) in the Galápagos region is examined using the calibrated HYCOM with forcing derived from the IPCC-AR4 climate model. Results show that although the oceanic variability in the entire Galápagos region is significantly affected by global climate change, the degree of such effects is inhomogeneous across the region. The upwelling region to the west of the Isabella Island shows relatively slower warming trends compared to the eastern Galápagos region. Diagnostic analysis suggests that the variability in the western Galápagos upwelling region is affected mainly by equatorial undercurrent (EUC) and Panama currents, while the central/east Galápagos is predominantly affected by both Peru and EUC currents. The inhomogeneous responses in different regions of the Galápagos Archipelago to future AGW can be explained by the incoherent changes of the various current systems in the Galápagos region as a result of global climate change. DA - 2013/// PY - 2013/// DO - 10.1155/2013/837432 VL - 2013 SP - SN - 1687-9317 ER - TY - JOUR TI - Atlantic Hurricanes and Climate Change. Part I: Experimental Design and Isolation of Thermodynamic Effects AU - Mallard, Megan S. AU - Lackmann, Gary M. AU - Aiyyer, Anantha AU - Hill, Kevin T2 - JOURNAL OF CLIMATE AB - Abstract The Weather Research and Forecasting (WRF) model is used in a downscaling experiment to simulate a portion of the Atlantic hurricane season both in present-day conditions and with modifications to include future thermodynamic changes. Temperature and moisture changes are derived from an ensemble of climate simulations from the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) A1B scenario and added to analyzed initial and lateral boundary conditions, leaving horizontal temperature gradients and vertical wind shear unaltered. This method of downscaling excludes future changes in shear and incipient disturbances, thereby isolating the thermodynamic component of climate change and its effect on tropical cyclone (TC) activity. The North Atlantic basin is simulated with 18- and 6-km grid spacing, and a four-member physics ensemble is composed by varying microphysical and boundary layer parameterization schemes. This ensemble is used in monthly simulations during an active (2005) and inactive (2009) season, and the simulations are able to capture the change in activity between the different years. TC frequency is better reproduced with use of 6-km grid spacing and explicitly simulated convection, relative to simulations with 18-km grid spacing. A detailed comparison of present-day and future ensemble results is provided in a companion study. DA - 2013/7// PY - 2013/7// DO - 10.1175/jcli-d-12-00182.1 VL - 26 IS - 13 SP - 4876-4893 SN - 1520-0442 KW - Tropical cyclones KW - Climate change KW - Hurricanes KW - typhoons KW - General circulation models KW - Mesoscale models ER - TY - JOUR TI - A physical and biological context for Karenia brevis seed populations on the northwest Florida shelf during July 2009 AU - McCulloch, Anita A. AU - Kamykowski, Daniel AU - Morrison, John M. AU - Thomas, Carrie J. AU - Pridgen, Katy Grabowski T2 - CONTINENTAL SHELF RESEARCH AB - The current effort focuses on characterizing physical and biological conditions across the northwest Florida shelf during summer as they influence Karenia brevis distributions and phytoplankton/microphytobenthos community associations. Phytoplankton and benthic algal communities were examined in the context of cross-shelf hydrography and sediment conditions during July 2009 between the 20 and 65 m isobaths off Panama City, FL. A towed undulating profiler (SeaSciences Acrobat) mapped water column characteristics between near-surface and ∼1 m above the sediment. A CTD/rosette provided hydrographic profiles and collected water samples at 17 cross-shelf locations at selected depths for nutrient concentration, phytoplankton biomass determination, and chemotaxonomic and taxonomic phytoplankton identification. In addition, a CTD/rosette time series sample set was collected following a holey sock drogue set at ∼34 m along the ∼50 m isobath, and cores were collected at eight stations approximately along the 30, 40 and 55 m isobaths. Cross-shelf, a pycnocline existed at ∼10 m depth, the 1% light level penetrated to ∼45 m depth, and nitrate–nitrite (NO3−+NO2−) concentrations increased in the lower 10 m of the water column to the 50 m isobath and then below 40-m depth to the 65 m isobath. A chlorophyll a peak occurred near-bottom between the 25 and 35 m isobaths. Gyroxanthin dinoflagellates (GD) representing K. brevis occurred across the shelf in near-surface and near-bottom waters. Near-surface GD co-occurred with cyanophytes at low density in the upper 20 m of the water column where NO3−+NO2− concentrations were low. Above sediments in the euphotic zone, near-bottom GD were most abundant between the 25 and 35 m isobaths where the NO3−+NO2− concentrations were 1–4 µM and where microphytobenthos competed for nutrient sources. Below the euphotic zone, GD were present near-bottom to the 60 m isobath where NO3−+NO2− concentrations approached 6 µM. A pattern consistent with dinoflagellate diel vertical migration was inferred at the 50-m isobath time-series station. The results provide insight into offshore K. brevis seed populations and their associations with other phytoplankton and microphytobenthos. Under summer light and nutrient conditions along the northwest Florida shelf, K. brevis coastal blooms may be seeded by diffuse near-surface populations during occasional downwelling conditions and by more concentrated near-bottom populations during more prevalent upwelling conditions. DA - 2013/7/15/ PY - 2013/7/15/ DO - 10.1016/j.csr.2013.05.001 VL - 63 SP - 94-111 SN - 1873-6955 KW - Benthic KW - Harmful algal bloom KW - Pelagic KW - Sediment KW - Upwelling ER - TY - JOUR TI - Vertebrate paleontology of the cloverly formation (Lower Cretaceous), I: Faunal composition, biogeographic relationships, and sampling AU - Oreska, M. P. J. AU - Carrano, M. T. AU - Dzikiewicz, K. M. T2 - Journal of Vertebrate Paleontology DA - 2013/// PY - 2013/// VL - 33 IS - 2 SP - 264-292 ER - TY - JOUR TI - Tracking the long-distance dispersal of marine organisms: sensitivity to ocean model resolution AU - Putman, Nathan F AU - He, Ruoying T2 - Journal of the Royal Society Interface DA - 2013/// PY - 2013/// VL - 10 IS - 81 SP - 20120979 ER - TY - JOUR TI - Return to use and performance following exploratory celiotomy for colic in horses: 195 cases (20032010) AU - Davis, W. AU - Fogle, C. A. AU - Gerard, M. P. AU - Levine, J. F. AU - Blikslager, A. T. T2 - EQUINE VETERINARY JOURNAL AB - Summary Reasons for performing study: There are few objective data on return to use and performance in horses following colic surgery. Objective: To investigate return to functional use of horses following colic surgery and factors associated with a negative outcome. Methods: The North Carolina State University Equine Colic Database was reviewed for horses that underwent exploratory celiotomy for colic (2003–2010). Horses were excluded from the study if they survived <6 months, had no intended use preoperatively, or if further data were not available at attempted follow‐up. Information retrieved included history, background, use, and selected pre‐, intra‐, and post operative factors. Telephone interviews were used to obtain follow‐up data. Logistic regression was used to investigate associations between clinical data and outcome, reported as odds ratios with a 95% confidence interval and corresponding P value. Results: Of patients surviving to 6 months, 133/195 (68%) were performing their intended use and 85/156 (54%) were at or above preoperative performance. At one year, 145/190 (76%) horses were performing their intended use and 101/153 (66%) were at or above preoperative performance. Animals were significantly less likely to return to use/performance if they had a previous celiotomy, stall rest for an orthopaedic condition, a nonstrangulating lesion type, incisional hernia, diarrhoea or laminitis. Conclusions: The overall prognosis for return to use and performance following colic surgery is fair to good. Multiple pre‐ and post operative factors may affect the likelihood of return to use and performance. Potential relevance: Targeted owner education regarding preoperative lameness, post operative rehabilitation and treatment for complications, such as incisional hernioplasty, may help inform owners about their horse's potential for return to use and performance following colic surgery. DA - 2013/3// PY - 2013/3// DO - 10.1111/j.2042-3306.2012.00615.x VL - 45 IS - 2 SP - 224-228 SN - 0425-1644 KW - horse KW - colic KW - surgery KW - prognosis KW - performance ER - TY - JOUR TI - Gravity-wave-induced perturbations in marine stratocumulus AU - Allen, G. AU - Vaughan, G. AU - Toniazzo, T. AU - Coe, H. AU - Connolly, P. AU - Yuter, S. E. AU - Burleyson, C. D. AU - Minnis, P. AU - Ayers, J. K. T2 - QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY AB - Abstract We discuss the role of atmospheric gravity waves in modulating cloud radiative and dynamical properties over the southeast Pacific. Satellite imagery and satellite‐retrieved cloud properties during October 2008 illustrate three distinct episodes of horizontal propagation of gravity wave trains across the large‐scale stratocumulus (Sc) cloud deck capping the local marine boundary layer. In one period, 7–9 October 2008, the waves modulated cloud‐top‐height by up to 400 m peak‐to‐trough, propagating perpendicular to the synoptic boundary layer flow with phase speed 15.3 m s −1 , period ∼1 h and horizontal wavelength 55 km. The gravity waves were observed to be non‐dispersive. These waves were first evident in the cloud deck near 30°S, 85°W during a 24 h period beginning at midday on 7 October 2008, and propagated northeastward toward the Peruvian coast for the following 48 h. During this time they induced both reversible and non‐reversible changes in cloud‐radiative and cloud‐dynamic properties, such that areas of clear sky developed in the troughs of passing wave‐fronts. These pockets of open cells persisted long after the passage of the gravity waves, advecting northwestward with the background wind. Using the analysis fields of the European Centre for Medium‐Range Weather Forecasts in conjunction with infrared and microwave satellite imagery, we show that these gravity waves emerged from a disturbed subtropical jet stream. The radiant of the waves was coincident in all cases with centres of large negative residuals in nonlinear balance, suggesting that geostrophic readjustment of sharply divergent flows associated with the disturbed jet provided a source for the wave energy. Conversely, gravity waves were not observed in more quiescent jet conditions. This case study highlights the important and irreversible effects that gravity waves propagating in the troposphere can have on cloud radiative properties (and hence surface radiation budgets) over a very wide area. It also highlights the importance of synoptic influence on Sc‐covered marine boundary layers. Copyright © 2012 Royal Meteorological Society DA - 2013/1// PY - 2013/1// DO - 10.1002/qj.1952 VL - 139 IS - 670 SP - 32-45 SN - 1477-870X KW - VOCALS KW - stratocumulus KW - gravity waves KW - pockets of open cells KW - cloud microphysics KW - scale interactions ER - TY - JOUR TI - Cold front induced changes on the Florida panhandle shelf during October 2008 AU - Kamykowski, D. AU - Pridgen, K. Grabowski AU - Morrison, J. M. AU - McCulloch, A. A. AU - Nyadjro, E. S. AU - Thomas, C. A. AU - Sinclair, G. A. T2 - CONTINENTAL SHELF RESEARCH AB - A significant step transition between seasonally stratified and destratified hydrographic conditions occurred during an October 2008 cruise to the Florida Panhandle Shelf along a cross-shelf transect that was sampled before and after a cold front passed through the area. Meteorological measurements from nearby ocean and land-based stations characterized the event. Cross-shelf continuous Acrobat profiles and discrete CTD stations characterized water column hydrographic patterns, while mid-shelf multicorer and box corer samples characterized sediment texture and nutrients. Water samples collected from selected depths biased toward the sediment interface were analyzed for nutrient content and phytoplankton community composition. Pre-front, the cross-shelf water column exhibited vertical stratification with complex temperature and salinity patterns. A prominent near-bottom chlorophyll a maximum of ∼1.5 μg L−1 between the 25–35 m isobaths occurred with the 1% light level at ∼18 m depth and a near-bottom nitrate+nitrite (NO3−+NO2−) maximum >3 μM between the 30–40 m isobaths. HPLC-determined phytoplankton community composition in the near-bottom chlorophyll a maximum consisted of gyroxanthin-containing dinoflagellates (Karenia brevis) and less abundant diatoms, both verified by FlowCAM analysis, mixed with detectable cryptophytes and chlorophytes. Sediment trends based on limited core replicates suggested the sediments were a potential source of nutrients to near-bottom populations of K. brevis and that shell hash could provide abundant pore space for K. brevis incursions. Between the 40–50 m isobaths, diatoms, cryptophytes and chlorophytes dominated near-bottom, gyroxanthin-containing dinoflagellates and prasinophytes occurred throughout the water column, and cyanophytes dominated near-surface. Post-front, the cross-shelf water column exhibited destratification with temperature and salinity increasing offshore. A chlorophyll a maximum of ∼0.75 μg Chl a L−1 left the sediment between 25–35 m isobaths and extended offshore especially in the lower water column with the 1% light level at ∼15 m depth and NO3−+NO2− concentrations ∼2 μM to the 60 m isobath. HPLC-determined phytoplankton community composition of the offshore plume retained the signature of gyroxanthin-containing dinoflagellates and chlorophytes. Between the 30–50 m isobaths, prasinophytes increased in the lower water column, while cyanophytes increased at all depths across the shelf. The observed step transition from stratification to destratification on the Florida Panhandle Shelf contributed to altered phytoplankton community patterns in response to predominant downwelling favorable winds. Pre-front, K. brevis cells were broadly distributed cross-shelf, but concentrated near-bottom between the 25–35 m isobaths and staged for prolific bloom seeding in response to the upwelling favorable west winds more typical of spring-summer. Post-front, K. brevis cells were mixed throughout the mid-shelf water column and were staged for diffuse bloom seeding in response to either the downwelling or upwelling favorable winds occurring fall-winter. Cyanophytes located predominantly near-surface offshore pre-front, were ubiquitous cross-shelf and more closely associated with K. brevis post-front. DA - 2013/2/15/ PY - 2013/2/15/ DO - 10.1016/j.csr.2012.12.006 VL - 54 SP - 52-66 SN - 1873-6955 KW - Karenia brevis KW - Pycnocline erosion KW - Winter mixing KW - Hydrographic transition KW - Pigment taxonomy KW - Gulf of Mexico ER - TY - JOUR TI - Chromophoric Dissolved Organic Matter and Dissolved Organic Carbon from Sea-Viewing Wide Field-of-View Sensor (SeaWiFS), Moderate Resolution Imaging Spectroradiometer (MODIS) and MERIS Sensors: Case Study for the Northern Gulf of Mexico AU - Tehrani, Nazanin Chaichi AU - Eurico J. D'Sa, AU - Osburn, Christopher L. AU - Bianchi, Thomas S. AU - Schaeffer, Blake A. T2 - REMOTE SENSING AB - Empirical band ratio algorithms for the estimation of colored dissolved organic matter (CDOM) and dissolved organic carbon (DOC) for Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Moderate Resolution Imaging Spectroradiometer (MODIS) and MERIS ocean color sensors were assessed and developed for the northern Gulf of Mexico. Match-ups between in situ measurements of CDOM absorption coefficients at 412 nm (aCDOM(412)) with that derived from SeaWiFS were examined using two previously reported reflectance band ratio algorithms. Results indicate better performance using the Rrs(510)/Rrs(555) (Bias = −0.045; RMSE = 0.23; SI = 0.49, and R2 = 0.66) than the Rrs(490)/Rrs(555) reflectance band ratio algorithm. Further, a comparison of aCDOM(412) retrievals using the Rrs(488)/Rrs(555) for MODIS and Rrs(510)/Rrs(560) for MERIS reflectance band ratios revealed better CDOM retrievals with MERIS data. Since DOC cannot be measured directly by remote sensors, CDOM as the colored component of DOC is utilized as a proxy to estimate DOC remotely. A seasonal relationship between CDOM and DOC was established for the summer and spring-winter with high correlation for both periods (R2~0.9). Seasonal band ratio empirical algorithms to estimate DOC were thus developed using the relationships between CDOM-Rrs and seasonal CDOM-DOC for SeaWiFS, MODIS and MERIS. Results of match-up comparisons revealed DOC estimates by both MODIS and MERIS to be relatively more accurate during summer time, while both of them underestimated DOC during spring-winter time. A better DOC estimate from MERIS in comparison to MODIS in spring-winter could be attributed to its similarity with the SeaWiFS band ratio CDOM algorithm. DA - 2013/3// PY - 2013/3// DO - 10.3390/rs5031439 VL - 5 IS - 3 SP - 1439-1464 SN - 2072-4292 KW - CDOM KW - DOC KW - SeaWiFS KW - MODIS KW - MERIS ER - TY - JOUR TI - A single parameter representation of hygroscopic growth and cloud condensation nucleus activity - Part 3: Including surfactant partitioning AU - Petters, M. D. AU - Kreidenweis, S. M. T2 - Atmospheric Chemistry and Physics DA - 2013/// PY - 2013/// VL - 13 IS - 2 SP - 1081-1091 ER - TY - JOUR TI - The carbon stable isotope biogeochemistry of streams, Taylor Valley, Antarctica AU - Lyons, W. B. AU - Leslie, D. L. AU - Harmon, R. S. AU - Neumann, K. AU - Welch, K. A. AU - Bisson, K. M. AU - McKnight, D. M. T2 - APPLIED GEOCHEMISTRY AB - The McMurdo Dry Valleys region of Antarctica is the largest ice-free region on the continent. This study reports the first C stable isotope measurements for dissolved inorganic C present in ephemeral streams in four dry valleys that flow for four to twelve weeks during the austral summer. One of these valleys, Taylor Valley, has been the focus of the McMurdo Dry Valleys Long-Term Ecological Research (MCM-LTER) program since 1993. Within Taylor Valley, numerous ephemeral streams deliver water to three perennially ice-covered, closed-basin lakes: Lake Fryxell, Lake Hoare, and Lake Bonney. The Onyx River in the Wright Valley, the longest river in Antarctica, flows for 40 km from the Wright Lower Glacier and Lake Brownworth at the foot of the glacier to Lake Vanda. Streamflow in the McMurdo Dry Valley streams is produced primarily from glacial melt, as there is no overland flow. However, hyporheic zone exchange can be a major hydrogeochemical process in these streams. Depending on landscape position, these streams vary in gradient, channel substrate, biomass abundance, and hyporheic zone extent. This study sampled streams from Taylor, Wright, Garwood, and Miers Valleys and conducted diurnal sampling of two streams of different character in Taylor Valley. In addition, transect sampling was undertaken of the Onyx River in Wright Valley. The δ13CPDB values from these streams span a range of greater than 14‰, from −9.4‰ to +5.1‰, with the majority of samples falling between −3‰ and +2‰, suggesting that the C stable isotope composition of dissolved C in McMurdo Dry Valley streams is largely inorganic in character. Because there are no vascular plants on this landscape and no groundwater input to these streams, atmospheric exchange is the dominant control on δ13C-DIC. DA - 2013/5// PY - 2013/5// DO - 10.1016/j.apgeochem.2012.08.019 VL - 32 SP - 26-36 SN - 1872-9134 ER - TY - JOUR TI - Rain on small tropical islands (vol 118, pg 2301, 2013) AU - Sobel, A. H. AU - Burleyson, C. D. AU - Yuter, S. E. AU - Biasutti, M. T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Key Points Observations of pitch‐angle distributions with repeated probe configurations Electron flux variations depend on probe relative to the flow type of electron PAD depends on position relative to the neutral sheet DA - 2013/3/16/ PY - 2013/3/16/ DO - 10.1002/jgrd.50205 VL - 118 IS - 5 SP - 2301-2302 SN - 2169-897X ER - TY - JOUR TI - New material of Mongolemys elegans Khosatzky and Mlynarski, 1971 (Testudines: Lindholmemydidae), from the Late Cretaceous of Mongolia with comments on bone histology and phylogeny AU - Cadena, E. A. AU - Ksepka, D. T. AU - Norell, M. A. T2 - American Museum Novitates DA - 2013/// PY - 2013/// IS - 3766 SP - 1-27 ER - TY - JOUR TI - Identifying human influences on atmospheric temperature AU - Santer, B. D. AU - Painter, J. F. AU - Mears, C. A. AU - Doutriaux, C. AU - Caldwell, P. AU - Arblaster, J. M. AU - Cameron-Smith, P. J. AU - Gillett, N. P. AU - Gleckler, P. J. AU - Lanzante, J. AU - Perlwitz, J. AU - Solomon, S. AU - Stott, P. A. AU - Taylor, K. E. AU - Terray, L. AU - Thorne, P. W. T2 - Proceedings of the National Academy of Sciences of the United States of America DA - 2013/// PY - 2013/// VL - 110 IS - 1 SP - 26-33 ER - TY - JOUR TI - Characterization of oil components from the Deepwater Horizon oil spill in the Gulf of Mexico using fluorescence EEM and PARAFAC techniques AU - Zhou, Zhengzhen AU - Guo, Laodong AU - Shiller, Alan M. AU - Lohrenz, Steven E. AU - Asper, Vernon L. AU - Osburn, Christopher L. T2 - MARINE CHEMISTRY AB - Three-dimensional (3D) fluorescence spectroscopy and parallel factor analysis (PARAFAC) were used to characterize oil components and to examine their fate and transformation processes during the unprecedented Deepwater Horizon oil spill in the Gulf of Mexico. Water samples were collected during two cruises in May and June 2010 soon after the spill began. Fluorescence excitation-emission matrix (EEM) spectra of seawater samples strongly resemble those of crude oil from the Macondo well and weathered oil collected from Gulf surface waters. This indicates the influence of oil on marine dissolved organic matter (DOM) which yielded elevated dissolved organic carbon (DOC) concentrations, higher UV–vis absorbance, and higher optically inferred molecular weight DOM in the water column. Two major types of DOM were found in the water column: one with low abundance but high optical activity and the other with high mass concentration yet low optical activity. Higher specific UV absorbance but lower spectral slope values observed for deep-water samples indicates the presence of less degraded or fresher crude oil in deep waters. Results of PARAFAC modeling revealed three oil-related components corresponding to crude and weathered oil in the water column: the most prominent one (namely C1) centered on Ex/Em 226/340 nm and the other two components (C2 and C6) centered on 236/360 and 252/311 nm, respectively. In addition, there is another DOM component (C3), partially representing chemically dispersed oil. Interestingly, the oil component ratios, an intensive property, varied with time and the degradation status of oil. We hypothesize that C2 (236/360 nm) is mostly a degraded product while C6 (252/311 nm) is a crude oil component with lower molecular weight, but at the same time, could be derived from oil degradation. Changes in fluorescence component ratios can thus be used as a compelling index to track the fate and transport of oil in marine environments. DA - 2013/1/20/ PY - 2013/1/20/ DO - 10.1016/j.marchem.2012.10.003 VL - 148 SP - 10-21 SN - 1872-7581 KW - Deepwater Horizon oil spill KW - Fluorescence EEMs KW - PARAFAC analysis KW - CDOM KW - Dissolved organic matter KW - Gulf of Mexico ER - TY - JOUR TI - A history of shifting fortunes for African penguins AU - Thomas, D. B. AU - Ksepka, D. T. T2 - Zoological Journal of the Linnean Society DA - 2013/// PY - 2013/// VL - 168 IS - 1 SP - 207-219 ER - TY - JOUR TI - A Shift in the Biogenic Silica of Sediment in the Larsen B Continental Shelf, Off the Eastern Antarctic Peninsula, Resulting from Climate Change AU - Sane, Elisabet AU - Isla, Enrique AU - Angeles Barcena, Maria AU - DeMaster, David J. T2 - PLOS ONE AB - In 2002, section B of the Larsen ice shelf, off of the Eastern Antarctic Peninsula, collapsed and created the opportunity to study whether the changes at the sea surface left evidence in the sedimentary record. Biogenic silica is major constituent of Antarctic marine sediment, and its presence in the sediment column is associated with diatom production in the euphotic zone. The abundance of diatom valves and the number of sponge spicules in the biogenic silica was analyzed to determine how the origin of the biogenic silica in the upper layers of the sediment column responded to recent environmental changes. Diatom valves were present only in the upper 2 cm of sediment, which roughly corresponds to the period after the collapse of the ice shelf. In contrast, sponge spicules, a more robust form of biogenic silica, were also found below the upper 2 cm layer of the sediment column. Our results indicate that in this region most of the biogenic silica in the sedimentary record originated from sponge spicules rather than diatoms during the time when the sea surface was covered by the Larsen ice shelf. Since the collapse of the ice shelf, the development of phytoplankton blooms and the consequent influx of diatom debris to the seabed have shifted the biogenic silica record to one dominated by diatom debris, as occurs in most of the Antarctic marine sediment. This shift provides further evidence of the anthropogenic changes to the benthic habitats of the Antarctic and will improve the interpretation of the sedimentary record in Polar Regions where these events occur. DA - 2013/1/2/ PY - 2013/1/2/ DO - 10.1371/journal.pone.0052632 VL - 8 IS - 1 SP - SN - 1932-6203 ER - TY - JOUR TI - The physical and chemical characteristics of marine primary organic aerosol: a review AU - Gantt, B. AU - Meskhidze, N. T2 - ATMOSPHERIC CHEMISTRY AND PHYSICS AB - Abstract. Knowledge of the physical characteristics and chemical composition of marine organic aerosols is needed for the quantification of their effects on solar radiation transfer and cloud processes. This review examines research pertinent to the chemical composition, size distribution, mixing state, emission mechanism, photochemical oxidation and climatic impact of marine primary organic aerosol (POA) associated with sea-spray. Numerous measurements have shown that both the ambient mass concentration of marine POA and size-resolved organic mass fraction of sea-spray aerosol are related to surface ocean biological activity. Recent studies have also indicated that fine mode (smaller than 200 nm in diameter) marine POA can have a size distribution independent from sea-salt, while coarse mode aerosols (larger than 1000 nm in diameter) are more likely to be internally mixed with sea-salt. Modelling studies have estimated global submicron marine POA emission rates of ~10 ± 5 Tg yr−1, with a considerable fraction of these emissions occurring over regions most susceptible to aerosol perturbations. Climate studies have found that marine POA can cause large local increases in the cloud condensation nuclei concentration and have a non-negligible influence on model assessments of the anthropogenic aerosol forcing of climate. Despite these signs of climate-relevance, the source strength, chemical composition, mixing state, hygroscopicity, cloud droplet activation potential, atmospheric aging and removal of marine POA remain poorly quantified. Additional laboratory, field, and modelling studies focused on the chemistry, size distribution and mixing state of marine POA are needed to better understand and quantify their importance. DA - 2013/// PY - 2013/// DO - 10.5194/acp-13-3979-2013 VL - 13 IS - 8 SP - 3979-3996 SN - 1680-7324 ER - TY - JOUR TI - Monitoring and understanding trends in extreme storms state of knowledge AU - Kunkel, K. E. AU - Karl, T. R. AU - Brooks, H. AU - Kossin, J. AU - Lawrimore, J. H. AU - Arndt, D. AU - Bosart, L. AU - Changnon, D. AU - Cutter, S. L. AU - Doesken, N. AU - Emanuel, K. Y. AU - Groisman, P. Y. AU - Katz, R. W. AU - Knutson, T. AU - O'Brien, J. AU - Paciorek, C. J. AU - Peterson, T. C. T2 - Bulletin of the American Meteorological Society DA - 2013/// PY - 2013/// VL - 94 IS - 4 SP - 499-514 ER - TY - JOUR TI - Impact of Moisture Flux and Freezing Level on Simulated Orographic Precipitation Errors over the Pacific Northwest AU - Lin, Yanluan AU - Colle, Brian A. AU - Yuter, Sandra E. T2 - JOURNAL OF HYDROMETEOROLOGY AB - Abstract Two cool seasons (November–March) of daily simulations using the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) over the Pacific Northwest are used to investigate orographic precipitation bias. Model simulations are compared with data from a radiosonde site at Salem, Oregon, just upstream (west) of the Oregon Cascades; precipitation gauges over a portion of the Pacific Northwest; and a National Weather Service Weather Surveillance Radar-1988 Doppler (WSR-88D) in Portland, Oregon. The 77 storms analyzed are partitioned into warm/cold storms based on the freezing level above/below the Oregon Cascades crest (~1600 m MSL). Although the seasonal precipitation is well simulated, the model has a tendency to overpredict surface precipitation for cold storms. The correlation between the upstream relative humidity–weighted integrated moisture transport and precipitation for warm storms (r2 = 0.81) is higher than that for cold storms (r2 = 0.54). Comparisons of model ice water content (IWC) and derived reflectivity with radar-retrieved IWC and observed reflectivity for the 38 well-simulated storms show reasonably good agreement for warm storms but an overprediction of IWC and reflectivity aloft for cold storms. One plausible reason for the persistent overprediction of IWC in cold storms might be related to the positive bias in snow depositional growth formulation in the model bulk microphysics parameterization. A favorable overlap of the maximum snow depositional growth region with the mountain wave ascent region in cold storms magnifies the bias and likely contributes to the precipitation overprediction. This study also highlights the benefit of using data aloft from an operational radar to complement surface precipitation gauges for model precipitation evaluation over mountainous terrain. DA - 2013/2// PY - 2013/2// DO - 10.1175/jhm-d-12-019.1 VL - 14 IS - 1 SP - 140-152 SN - 1525-755X ER - TY - JOUR TI - Identifying the MJO, Equatorial Waves, and Their Impacts Using 32 Years of HIRS Upper-Tropospheric Water Vapor AU - Schreck, Carl J., III AU - Shi, Lei AU - Kossin, James P. AU - Bates, John J. T2 - JOURNAL OF CLIMATE AB - Abstract The Madden–Julian oscillation (MJO) and convectively coupled equatorial waves are the dominant modes of synoptic-to-subseasonal variability in the tropics. These systems have frequently been examined with proxies for convection such as outgoing longwave radiation (OLR). However, upper-tropospheric water vapor (UTWV) gives a more complete picture of tropical circulations because it is more sensitive to the drying and warming associated with subsidence. Previous studies examined tropical variability using relatively short (3–7 yr) UTWV datasets. Intersatellite calibration of data from the High Resolution Infrared Radiation Sounder (HIRS) has recently produced a homogeneous 32-yr climate data record of UTWV for 200–500 hPa. This study explores the utility of HIRS UTWV for identifying the MJO and equatorial waves. Spectral analysis shows that the MJO and equatorial waves stand out above the low-frequency background in UTWV, similar to previous findings with OLR. The fraction of variance associated with the MJO and equatorial Rossby waves is actually greater in UTWV than in OLR. Kelvin waves, on the other hand, are overshadowed in UTWV by horizontal advection from extratropical Rossby waves. For the MJO, UTWV identifies subsidence drying in the subtropics, poleward of the convection. These dry anomalies are associated with the MJO’s subtropical Rossby gyres. MJO events with dry anomalies over the central North Pacific Ocean also amplify the 200-hPa flow pattern over North America 7 days later. These events cannot be identified using equatorial OLR alone, which demonstrates that UTWV is a useful supplement for identifying the MJO, equatorial waves. DA - 2013/2// PY - 2013/2// DO - 10.1175/jcli-d-12-00034.1 VL - 26 IS - 4 SP - 1418-1431 SN - 1520-0442 ER - TY - JOUR TI - Energy Dispersion in African Easterly Waves AU - Diaz, Michael AU - Aiyyer, Anantha T2 - JOURNAL OF THE ATMOSPHERIC SCIENCES AB - Abstract The existence of an upstream (eastward) group velocity for African easterly waves (AEWs) is shown based on single-point lag regressions using gridded reanalysis data from 1990 to 2010. The eastward energy dispersion is consistent with the direction of ageostrophic geopotential flux vectors. A local eddy kinetic energy (EKE) budget reveals that, early in the life cycle of AEWs, growth rate due to geopotential flux convergence exceeds baroclinic and barotropic growth rates. Later in the life cycle, EKE decay due to geopotential flux divergence cancels or exceeds baroclinic and barotropic growth. A potential vorticity (PV) budget is used to diagnose tendencies related to group propagation. Although both upstream and downstream group speeds are possible because of the reversal in the mean meridional PV gradient, upstream propagation associated with the positive poleward PV gradient dominates wave packet evolution. Analogous to the concept of downstream development of midlatitude baroclinic waves, new AEWs develop preferentially upstream of the older ones, thus providing a mechanism for seeding new waves. It is suggested that these results are also relevant to AEW intermittency and storm-track structure. DA - 2013/1// PY - 2013/1// DO - 10.1175/jas-d-12-019.1 VL - 70 IS - 1 SP - 130-145 SN - 1520-0469 ER - TY - JOUR TI - Adjusting the Wind Stress Drag Coefficient in Storm Surge Forecasting Using an Adjoint Technique AU - Peng, Shiqiu AU - Li, Yineng AU - Xie, Lian T2 - JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY AB - Abstract A three-dimensional ocean model and its adjoint model are used to adjust the drag coefficient in the calculation of wind stress for storm surge forecasting. A number of identical twin experiments (ITEs) with different error sources imposed are designed and performed. The results indicate that when the errors come from the wind speed, the drag coefficient is adjusted to an “optimal value” to compensate for the wind errors, resulting in significant improvements of the specific storm surge forecasting. In practice, the “true” drag coefficient is unknown and the wind field, which is usually calculated by an empirical parameter model or a numerical weather prediction model, may contain large errors. In addition, forecasting errors may also come from imperfect model physics and numerics, such as insufficient resolution and inaccurate physical parameterizations. The results demonstrate that storm surge forecasting errors can be reduced through data assimilation by adjusting the drag coefficient regardless of the error sources. Therefore, although data assimilation may not fix model imperfection, it is effective in improving storm surge forecasting by adjusting the wind stress drag coefficient using the adjoint technique. DA - 2013/3// PY - 2013/3// DO - 10.1175/jtech-d-12-00034.1 VL - 30 IS - 3 SP - 590-608 SN - 1520-0426 ER - TY - JOUR TI - Underwater acoustic records from the March 2009 eruption of Hunga Ha'apai-Hunga Tonga volcano in the Kingdom of Tonga AU - Bohnenstiehl, DelWayne R. AU - Dziak, Robert P. AU - Matsumoto, Haru AU - Lau, T. -K. Andy T2 - JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH AB - Abstract A network of autonomous underwater hydrophones is used to monitor acoustic activity associated with Hunga Ha'apai-Hunga Tonga volcano during a period of 15 months. The data provide a continuous record spanning a surtseyan eruption (VEI 2) in March of 2009, which input ~ 10 13  J of acoustic energy into the ocean soundscape. In the months before the eruption, the volcano can be identified as an intermittent source of ambient noise. The period of seismic unrest that precedes the eruption begins at 15:11 UTC on 16 March (04:11 LT on 17 March), approximately 7 h before the first satellite confirmation of eruptive activity and 14 h before the first eyewitness reports. The initial seismic activity, which includes a single 4.8 m b event at 15:25, evolves as a typical foreshock–mainshock–aftershock sequence. By 15:38, however, the rate of small earthquakes begins to increase, marking the onset of the seismic swarm. The period of highest-amplitude acoustic energy release between 16:40 and ~ 17:10 is interpreted to mark the opening of the volcanic conduit. By 19:00 on 16 March, the acoustic signature of the volcano is marked by a continuous wide-band (1–20 Hz) noise and a set of transient very-broadband (1–125 Hz) explosion signals. This activity is characteristic of the main surtseyan phase of the eruption. Both the intensity of explosions and the amplitude of the lower frequency wide-band noise decay through time, and eruptive activity likely ends at ~ 09:00 on 19 March, ~ 2.7 days after the initiation of seismic activity. At this time the continuous low frequency noise decays to near background levels and signal coherence drops suddenly. Low-level acoustic unrest persists through June of 2009, after which the volcano becomes acoustically dormant during the remaining ten months of monitoring. The analysis of volcano-acoustic signals associated with Hunga Ha'apai-Hunga Tonga volcano highlights the potential role of regional hydroacoustic monitoring in assessing volcanic hazards in arc settings. DA - 2013/1/1/ PY - 2013/1/1/ DO - 10.1016/j.jvolgeores.2012.08.014 VL - 249 SP - 12-24 SN - 1872-6097 KW - Hunga Ha'apai-Hunga Tonga Volcano KW - Surtseyan eruption KW - Acoustics KW - Hydrophone monitoring KW - Arc volcanism ER - TY - JOUR TI - U.S. climate reference network after one decade of operations status and assessment AU - Diamond, H. J. AU - Karl, T. R. AU - Palecki, M. A. AU - Baker, C. B. AU - Bell, J. E. AU - Leeper, R. D. AU - Easterling, D. R. AU - Lawrimore, J. H. AU - Meyers, T. P. AU - Helfert, M. R. AU - Goodge, G. AU - Thorne, P. W. T2 - Bulletin of the American Meteorological Society DA - 2013/// PY - 2013/// VL - 94 IS - 4 SP - 485-498 ER - TY - JOUR TI - Incorporation and mineralization of TNT and other anthropogenic organics by natural microbial assemblages from a small, tropical estuary AU - Montgomery, Michael T. AU - Coffin, Richard B. AU - Boyd, Thomas J. AU - Osburn, Christopher L. T2 - Environmental Pollution AB - 2,4,6-Trinitrotoluene (TNT) metabolism was compared across salinity transects in Kahana Bay, a small tropical estuary on Oahu, HI. In surface water, TNT incorporation rates (range: 3-121 μg C L(-1) d(-1)) were often 1-2 orders of magnitude higher than mineralization rates suggesting that it may serve as organic nitrogen for coastal microbial assemblages. These rates were often an order of magnitude more rapid than those for RDX and two orders more than HMX. During average or high stream flow, TNT incorporation was most rapid at the riverine end member and generally decreased with increasing salinity. This pattern was not seen during low flow periods. Although TNT metabolism was not correlated with heterotrophic growth rate, it may be related to metabolism of other aromatic compounds. With most TNT ring-carbon incorporation efficiencies at greater than 97%, production of new biomass appears to be a more significant product of microbial TNT metabolism than mineralization. DA - 2013/3// PY - 2013/3// DO - 10.1016/j.envpol.2012.11.036 VL - 174 SP - 257-264 J2 - Environmental Pollution LA - en OP - SN - 0269-7491 UR - http://dx.doi.org/10.1016/j.envpol.2012.11.036 DB - Crossref KW - TNT KW - Incorporation KW - Mineralization KW - Biodegradation KW - Bacteria KW - Kahana Bay ER - TY - JOUR TI - Fossil evidence of wing shape in a stem relative of swifts and hummingbirds (Aves, Pan-Apodiformes) AU - Ksepka, D. T. AU - Clarke, J. A. AU - Nesbitt, S. J. AU - Kulp, F. B. AU - Grande, L. T2 - Proceedings of the Royal Society of London. Series B DA - 2013/// PY - 2013/// VL - 280 IS - 1761 ER - TY - JOUR TI - Enhanced transfer of terrestrially derived carbon to the atmosphere in a flooding event AU - Bianchi, Thomas S. AU - Garcia-Tigreros, Fenix AU - Yvon-Lewis, Shari A. AU - Shields, Michael AU - Mills, Heath J. AU - Butman, David AU - Osburn, Christopher AU - Raymond, Peter AU - Shank, G. Christopher AU - DiMarco, Steven F. AU - Walker, Nan AU - Reese, Brandi Kiel AU - Mullins-Perry, Ruth AU - Quigg, Antonietta AU - Aiken, George R. AU - Grossman, Ethan L. T2 - Geophysical Research Letters AB - Abstract Rising CO 2 concentration in the atmosphere, global climate change, and the sustainability of the Earth's biosphere are great societal concerns for the 21st century. Global climate change has, in part, resulted in a higher frequency of flooding events, which allow for greater exchange between soil/plant litter and aquatic carbon pools. Here we demonstrate that the summer 2011 flood in the Mississippi River basin, caused by extreme precipitation events, resulted in a “flushing” of terrestrially derived dissolved organic carbon (TDOC) to the northern Gulf of Mexico. Data from the lower Atchafalaya and Mississippi rivers showed that the DOC flux to the northern Gulf of Mexico during this flood was significantly higher than in previous years. We also show that consumption of radiocarbon‐modern TDOC by bacteria in floodwaters in the lower Atchafalaya River and along the adjacent shelf contributed to northern Gulf shelf waters changing from a net sink to a net source of CO 2 to the atmosphere in June and August 2011. This work shows that enhanced flooding, which may or may not be caused by climate change, can result in rapid losses of stored carbon in soils to the atmosphere via processes in aquatic ecosystems. DA - 2013/1/8/ PY - 2013/1/8/ DO - 10.1029/2012gl054145 VL - 40 IS - 1 SP - 116-122 J2 - Geophys. Res. Lett. LA - en OP - SN - 0094-8276 UR - http://dx.doi.org/10.1029/2012GL054145 DB - Crossref ER - TY - JOUR TI - Editorial-The 3rd International Workshop on Modeling the Ocean (IWMO 2011) AU - Oey, Lie-Yauw AU - Ezer, Tal AU - Qiu, Bo AU - Berntsen, Jarle AU - He, Ruoying T2 - OCEAN DYNAMICS DA - 2013/3// PY - 2013/3// DO - 10.1007/s10236-013-0595-3 VL - 63 IS - 2-3 SP - 307-309 SN - 1616-7228 ER - TY - JOUR TI - Detection and characterization of heavy drizzle cells within subtropical marine stratocumulus using AMSR-E 89-GHz passive microwave measurements AU - Miller, M. A. AU - Yuter, S. E. T2 - ATMOSPHERIC MEASUREMENT TECHNIQUES AB - Abstract. This empirical study demonstrates the feasibility of using 89-GHz Advanced Microwave Scanning Radiometer–Earth Observing System (AMSR-E) passive microwave brightness temperature data to detect heavily drizzling cells within subtropical marine stratocumulus. For the purpose of this paper, we define heavily drizzling cells as areas ≥ 6 km × 4 km with C-band Z > 0 dBZ; equivalent to > 0.084 mm h−1. A binary heavy drizzle product is described that can be used to determine areal and feature statistics of drizzle cells within the major marine stratocumulus regions. Current satellite liquid water path (LWP) and cloud radar products capable of detecting drizzle are either lacking in resolution (AMSR-E LWP), diurnal coverage (MODIS LWP), or spatial coverage (CloudSat). The AMSR-E 89-GHz data set at 6 km × 4 km spatial resolution is sufficient for resolving individual heavily drizzling cells. Radiant emission at 89 GHz by liquid-water cloud and precipitation particles from drizzling cells in marine stratocumulus regions yields local maxima in brightness temperature against an otherwise cloud-free background brightness temperature. The background brightness temperature is primarily constrained by column-integrated water vapor for moderate sea surface temperatures. Clouds containing ice are screened out. Once heavily drizzling pixels are identified, connected pixels are grouped into discrete drizzle cell features. The identified drizzle cells are used in turn to determine several spatial statistics for each satellite scene, including drizzle cell number and size distribution. The identification of heavily drizzling cells within marine stratocumulus regions with satellite data facilitates analysis of seasonal and regional drizzle cell occurrence and the interrelation between drizzle and changes in cloud fraction. DA - 2013/// PY - 2013/// DO - 10.5194/amt-6-1-2013 VL - 6 IS - 1 SP - 1-13 SN - 1867-8548 ER - TY - JOUR TI - Crocodyliform Feeding Traces on Juvenile Ornithischian Dinosaurs from the Upper Cretaceous (Campanian) Kaiparowits Formation, Utah AU - Boyd, Clint A. AU - Drumheller, Stephanie K. AU - Gates, Terry A. T2 - PLOS ONE AB - Crocodyliforms serve as important taphonomic agents, accumulating and modifying vertebrate remains. Previous discussions of Mesozoic crocodyliform feeding in terrestrial and riverine ecosystems have often focused on larger taxa and their interactions with equally large dinosaurian prey. However, recent evidence suggests that the impact of smaller crocodyliforms on their environments should not be discounted. Here we present direct evidence of feeding by a small crocodyliform on juvenile specimens of a 'hypsilophodontid' dinosaur from the Upper Cretaceous (Campanian) Kaiparowits Formation of southern Utah. Diagnostic crocodyliform bite marks present on a left scapula and a right femur, as well as a partial probable crocodyliform tooth crown (ovoid in cross-section) preserved within a puncture on the right femur, comprise the bulk of the feeding evidence. Computed tomography scans of the femoral puncture reveal impact damage to the surrounding bone and that the distal tip of the embedded tooth was missing prior to the biting event. This is only the second reported incidence of a fossil crocodyliform tooth being found embedded directly into prey bone. These bite marks provide insight into the trophic interactions of the ecosystem preserved in the Kaiparowits Formation. The high diversity of crocodyliforms within this formation may have led to accentuated niche partitioning, which seems to have included juvenile dinosaurian prey. DA - 2013/2/27/ PY - 2013/2/27/ DO - 10.1371/journal.pone.0057605 VL - 8 IS - 2 SP - SN - 1932-6203 ER - TY - JOUR TI - Molecular analyses of dinosaur osteocytes support the presence of endogenous molecules AU - Schweitzer, Mary Higby AU - Zheng, Wenxia AU - Cleland, Timothy P. AU - Bern, Marshall T2 - BONE AB - The discovery of soft, transparent microstructures in dinosaur bone consistent in morphology with osteocytes was controversial. We hypothesize that, if original, these microstructures will have molecular features in common with extant osteocytes. We present immunological and mass spectrometry evidence for preservation of proteins comprising extant osteocytes (Actin, Tubulin, PHEX, Histone H4) in osteocytes recovered from two non-avian dinosaurs. Furthermore, antibodies to DNA show localized binding to these microstructures, which also react positively with DNA intercalating stains propidium iodide (PI) and 4',6'-diamidino-2-phenylindole dihydrochloride (DAPI). Each antibody binds dinosaur cells in patterns similar to extant cells. These data are the first to support preservation of multiple proteins and to present multiple lines of evidence for material consistent with DNA in dinosaurs, supporting the hypothesis that these structures were part of the once living animals. We propose mechanisms for preservation of cells and component molecules, and discuss implications for dinosaurian cellular biology. DA - 2013/1// PY - 2013/1// DO - 10.1016/j.bone.2012.10.010 VL - 52 IS - 1 SP - 414-423 SN - 1873-2763 KW - Osteocytes KW - Fossil KW - Dinosaur KW - T. rex KW - Ancient proteins KW - Ancient DNA ER - TY - JOUR TI - Misuse of the phytoplanktonzooplankton dichotomy: the need to assign organisms as mixotrophs within plankton functional types AU - Flynn, Kevin J. AU - Stoecker, Diane K. AU - Mitra, Aditee AU - Raven, John A. AU - Glibert, Patricia M. AU - Hansen, Per Juel AU - Graneli, Edna AU - Burkholder, Joann M. T2 - JOURNAL OF PLANKTON RESEARCH AB - The classic portrayal of plankton is dominated by phytoplanktonic primary producers and zooplanktonic secondary producers. In reality, many if not most plankton traditionally labelled as phytoplankton or microzooplankton should be identified as mixotrophs, contributing to both primary and secondary production. Mixotrophic protists (i.e. single-celled eukaryotes that perform photosynthesis and graze on particles) do not represent a minor component of the plankton, as some form of inferior representatives of the past evolution of protists; they represent a major component of the extant protist plankton, and one which could become more dominant with climate change. The implications for this mistaken identification, of the incorrect labelling of mixotrophs as “phytoplankton” or “microzooplankton”, are great. It extends from the (mis)use of photopigments as indicators of primary production performed by strict photoautotrophs rather than also (co)locating mixotrophic activity, through to the inadequacy of plankton functional type descriptions in models (noting that mixotrophic production in the individual organism is not a simple sum of phototrophy and heterotrophy). We propose that mixotrophy should be recognized as a major contributor to plankton dynamics, with due effort expended in field and laboratory studies, and should no longer be side-lined in conceptual food webs or in mathematical models. DA - 2013/// PY - 2013/// DO - 10.1093/plankt/fbs062 VL - 35 IS - 1 SP - 3-11 SN - 1464-3774 KW - phytoplankton KW - microzooplankton KW - primary production KW - secondary production KW - mixotroph KW - model KW - plankton functional type ER - TY - JOUR TI - Dependence of mean square slope on wave state and its application in altimeter wind speed retrieval AU - Li, S. Q. AU - Zhao, D. L. AU - Zhou, L. M. AU - Liu, B. T2 - International Journal of Remote Sensing DA - 2013/// PY - 2013/// VL - 34 IS - 1 SP - 264-275 ER -