TY - CONF TI - Work in progress to estimate a Latest Pleistocene slip rate for the Banning Strand of the San Andreas Fault near North Palm Springs C2 - 2016/8// C3 - Southern California Earthquake Center Annual Meeting DA - 2016/8// ER - TY - CONF TI - Late Pleistocene deformation at Aljezur fault system, SW Portugal: Seismicity triggering within a slow tectonic rate setting and relationships with sea-level rise C2 - 2016/8/11/ C3 - International INQUA Meeting on Paleoseismology, Active Tectonics and Archaeseismology, DA - 2016/8/11/ ER - TY - CONF TI - Slip variability and temporal clustering along the Imperial fault at Mesquite Basin, Imperial Valley, California, and possible through-going rupture to the San Andreas Fault C2 - 2016/8// DA - 2016/8// ER - TY - JOUR TI - Testing fault growth models with low-temperature thermochronology in the northwest Basin and Range, USA T2 - Tectonics AB - Abstract Common fault growth models diverge in predicting how faults accumulate displacement and lengthen through time. A paucity of field‐based data documenting the lateral component of fault growth hinders our ability to test these models and fully understand how natural fault systems evolve. Here we outline a framework for using apatite (U‐Th)/He thermochronology (AHe) to quantify the along‐strike growth of faults. To test our framework, we first use a transect in the normal fault‐bounded Jackson Mountains in the Nevada Basin and Range Province, then apply the new framework to the adjacent Pine Forest Range. We combine new and existing cross sections with 18 new and 16 existing AHe cooling ages to determine the spatiotemporal variability in footwall exhumation and evaluate models for fault growth. Three age‐elevation transects in the Pine Forest Range show that rapid exhumation began along the range‐front fault between approximately 15 and 11 Ma at rates of 0.2–0.4 km/Myr, ultimately exhuming approximately 1.5–5 km. The ages of rapid exhumation identified at each transect lie within data uncertainty, indicating concomitant onset of faulting along strike. We show that even in the case of growth by fault‐segment linkage, the fault would achieve its modern length within 3–4 Myr of onset. Comparison with the Jackson Mountains highlights the inadequacies of spatially limited sampling. A constant fault‐length growth model is the best explanation for our thermochronology results. We advocate that low‐temperature thermochronology can be further utilized to better understand and quantify fault growth with broader implications for seismic hazard assessments and the coevolution of faulting and topography. DA - 2016/10// PY - 2016/10// DO - 10.1002/2016tc004211 UR - http://dx.doi.org/10.1002/2016tc004211 ER - TY - JOUR TI - Controls on the stable isotope compositions of travertine from hyperalkaline springs in Oman: Insights from clumped isotope measurements AU - Falk, E.S. AU - Guo, W. AU - Paukert, A.N. AU - Matter, J.M. AU - Mervine, E.M. AU - Kelemen, P.B. T2 - Geochimica et Cosmochimica Acta AB - Carbonate formation at hyperalkaline springs is typical of serpentinization in peridotite massifs worldwide. These travertines have long been known to exhibit large variations in their carbon and oxygen isotope compositions, extending from apparent equilibrium values to highly depleted values. However, the exact causes of these variations are not well constrained. We analyzed a suite of well-characterized fresh carbonate precipitates and travertines associated with hyperalkaline springs in the peridotite section of the Samail ophiolite, Sultanate of Oman, and found their clumped isotope compositions vary systematically with formation environments. Based on these findings, we identified four main processes controlling the stable isotope compositions of these carbonates. These include hydroxylation of CO2, partial isotope equilibration of dissolved inorganic carbon, mixing between isotopically distinct carbonate end-members, and post-depositional recrystallization. Most notably, in fresh crystalline films on the surface of hyperalkaline springs and in some fresh carbonate precipitates from the bottom of hyperalkaline pools, we observed large enrichments in Δ47 (up to ∼0.2‰ above expected equilibrium values) which accompany depletions in δ18O and δ13C, yielding about 0.01‰ increase in Δ47 and 1.1‰ decrease in δ13C for every 1‰ decrease in δ18O, relative to expected equilibrium values. This disequilibrium trend, also reflected in preserved travertines ranging in age from modern to ∼40,000 years old, is interpreted to arise mainly from the isotope effects associated with the hydroxylation of CO2 in high-pH fluids and agrees with our first-order theoretical estimation. In addition, in some fresh carbonate precipitates from the bottom of hyperalkaline pools and in subsamples of one preserved travertine terrace, we observed additional enrichments in Δ47 at intermediate δ13C and δ18O, consistent with mixing between isotopically distinct carbonate end-members. Our results suggest that carbonate clumped isotope analysis can be a valuable tool for identifying and distinguishing processes not readily apparent from the carbonate bulk stable isotope compositions alone, e.g., kinetic effects or mixing of different carbonate end-members, which can significantly alter both the apparent formation temperatures and apparent radiocarbon ages. The isotope trends observed in these travertine samples could be applied more broadly to identify extinct hyperalkaline springs in terrestrial and extraterrestrial environments, to better constrain the formation conditions and post-depositional alteration of hyperalkaline spring carbonates, and to extract potential paleoclimate information. DA - 2016/11// PY - 2016/11// DO - 10.1016/j.gca.2016.06.026 UR - http://dx.doi.org/10.1016/j.gca.2016.06.026 ER - TY - JOUR TI - A new approach for monthly updates of anthropogenic sulfur dioxide emissions from space: Application to China and implications for air quality forecasts AU - Wang, Yi AU - Wang, Jun AU - Xu, Xiaoguang AU - Henze, Daven K. AU - Wang, Yuxuan AU - Qu, Zhen T2 - Geophysical Research Letters AB - Abstract SO 2 emissions, the largest source of anthropogenic aerosols, can respond rapidly to economic and policy driven changes. However, bottom‐up SO 2 inventories have inherent limitations owing to 24–48 months latency and lack of month‐to‐month variation in emissions (especially in developing countries). This study develops a new approach that integrates Ozone Monitoring Instrument (OMI) SO 2 satellite measurements and GEOS‐Chem adjoint model simulations to constrain monthly anthropogenic SO 2 emissions. The approach's effectiveness is demonstrated for 14 months in East Asia; resultant posterior emissions not only capture a 20% SO 2 emission reduction in Beijing during the 2008 Olympic Games but also improve agreement between modeled and in situ surface measurements. Further analysis reveals that posterior emissions estimates, compared to the prior, lead to significant improvements in forecasting monthly surface and columnar SO 2 . With the pending availability of geostationary measurements of tropospheric composition, we show that it may soon be possible to rapidly constrain SO 2 emissions and associated air quality predictions at fine spatiotemporal scales. DA - 2016/9/28/ PY - 2016/9/28/ DO - 10.1002/2016gl070204 VL - 43 IS - 18 SP - 9931-9938 UR - http://dx.doi.org/10.1002/2016gl070204 ER - TY - JOUR TI - Modeling p CO 2 variability in the Gulf of Mexico AU - Xue, Zuo AU - He, Ruoying AU - Fennel, Katja AU - Wei-Jun, Cai AU - Lohrenz, Steven AU - Huang, Wei-Jen AU - Tian, Hanqin AU - Ren, Wei AU - Zang, Zhengchen T2 - Biogeosciences DA - 2016/// PY - 2016/// VL - 13 IS - 15 SP - 4359 ER - TY - CONF TI - Connecting the Mississippi River with Carbon Variability in the Gulf of Mexico AU - Xue, ZG AU - He, R AU - Fennel, K AU - Cai, WJ AU - Lohrenz, SE AU - Huang, WJ AU - Tian, H AU - Ren, W C2 - 2016/// C3 - American Geophysical Union, Ocean Sciences Meeting 2016, abstract# AH33A-04 DA - 2016/// ER - TY - CONF TI - Anthropogenic and climatic controls on carbon and nitrogen exports from Mississippi river basin to Gulf of Mexico during 1800-2100: Implications for hypoxia and ocean acidification AU - Tian, H AU - Yang, J AU - Zhang, B AU - Pan, S AU - Lohrenz, SE AU - Cai, WJ AU - He, R AU - Xue, ZG AU - Lu, C AU - Ren, W AU - others C2 - 2016/// C3 - AGU Fall Meeting Abstracts DA - 2016/// ER - TY - JOUR TI - Spatial and seasonal variation in leaf temperature within the canopy of a tropical forest AU - Rey-Sánchez, AC AU - Slot, M AU - Posada, JM AU - Kitajima, K T2 - Climate Research AB - CR Climate Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials CR 71:75-89 (2016) - DOI: https://doi.org/10.3354/cr01427 Spatial and seasonal variation in leaf temperature within the canopy of a tropical forest A. Camilo Rey-Sánchez1,2,5,*, Martijn Slot2,3, Juan M. Posada1, Kaoru Kitajima2,3,4 1Biology Program, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Cr. 24 # 63C-69, Bogotá, D.C., Colombia 2Smithsonian Tropical Research Institute, Apartado 0843-03092, Balboa, Republic of Panamá 3Department of Biology, University of Florida, Gainesville, FL 32611, USA 4Division of Forest and Biomaterials Science, Kyoto University, Kyoto 606-8502, Japan 5Present address: The Ohio State University, Department of Civil, Environmental and Geodetic Engineering, 2070 Neil Ave., Columbus, OH 43210, USA *Corresponding author: reysanchez.1@osu.edu ABSTRACT: Understanding leaf temperature (Tleaf) variation in the canopy of tropical forests is critical for accurately calculating net primary productivity because plant respiration and net photosynthesis are highly sensitive to temperature. The objectives of this study were to (1) quantify the spatiotemporal variation of Tleaf in a semi-deciduous tropical forest in Panama and (2) create a season-specific empirical model to predict Tleaf in the canopy. To achieve this, we used a 42 m tall construction crane for canopy access and monitored the microenvironment within the canopy of mature, 20-35 m tall trees of 5 tropical tree species during the wet and the dry season. Tleaf was correlated to photosynthetic photon flux density (PPFD) in the wet season but not in the dry season, possibly due to seasonal differences in wind speed, physiology, and canopy phenology. A structural equation model showed that Tleaf is best explained by air temperature (Tair) and PPFD in the wet season, whereas in the dry season, Tair alone predicted most of the variation in Tleaf. These results suggest the utility of an empirical approach to estimate Tleaf variability where simple meteorological data are available. This approach can be incorporated in future models of vegetation-atmosphere carbon and water exchange models of mature tropical forests with similar seasonality. KEY WORDS: Leaf temperature · Tropical forest · Canopy research · Carbon modeling Full text in pdf format PreviousCite this article as: Rey-Sánchez AC, Slot M, Posada JM, Kitajima K (2016) Spatial and seasonal variation in leaf temperature within the canopy of a tropical forest. Clim Res 71:75-89. https://doi.org/10.3354/cr01427 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in CR Vol. 71, No. 1. Online publication date: November 30, 2016 Print ISSN: 0936-577X; Online ISSN: 1616-1572 Copyright © 2016 Inter-Research. DA - 2016/11/30/ PY - 2016/11/30/ DO - 10.3354/cr01427 VL - 71 IS - 1 SP - 75-89 J2 - Clim. Res. LA - en OP - SN - 0936-577X 1616-1572 UR - http://dx.doi.org/10.3354/cr01427 DB - Crossref ER - TY - JOUR TI - Benthic foraminiferal shell weight: Deglacial species-specific responses from the Santa Barbara Basin AU - Davis, Catherine V. AU - Myhre, Sarah E. AU - Hill, Tessa M. T2 - Marine Micropaleontology AB - Here we present a record of size-normalized shell weight for four species of benthic foraminifera through a period of rapid environmental change during the most recent deglaciation (Santa Barbara Basin, CA). A strong Oxygen Minimum Zone (OMZ), the product of high surface productivity and poor ventilation, characterizes the eastern Pacific; this subsurface zone is mechanistically coupled with high concentrations of dissolved inorganic carbon. The OMZ migrated vertically during warming of the last deglaciation, leading to rapid shifts in the oxygenation and inorganic carbon system of the benthos. The size-normalized weight (SNW) of benthic foraminifers Uvigerina peregrina, Bolivina interjuncta, and Bolivina tumida reflects only the broad trends of the vertical migration of the OMZ, and inorganic carbon system, overshadowed by clear species-specific trends. The relative importance of OMZ migrations versus other environmental variables and optimal growth conditions differs across species of benthic foraminifera. In U. peregrina, SNW primarily peaks with foraminiferal density and increased abundance of that species, while B. interjuncta and B. tumida increase in SNW with a shrinking of the OMZ (and carbon maximum) in the late Holocene. Bolivina argentea shows no long-term trends in SNW potentially due to its ability to migrate through the sediment. Our results suggest that, while inorganic carbon and dissolved oxygen may play a role in determining shell weight across species of benthic foraminifera, neither parameter alone is responsible for changes in benthic foraminiferal shell weight in the fossil record. DA - 2016/4// PY - 2016/4// DO - 10.1016/j.marmicro.2016.02.002 VL - 124 SP - 45-53 J2 - Marine Micropaleontology LA - en OP - SN - 0377-8398 UR - http://dx.doi.org/10.1016/j.marmicro.2016.02.002 DB - Crossref ER - TY - JOUR TI - Seasonality in planktic foraminifera of the central California coastal upwelling region AU - Davis, Catherine V. AU - Hill, Tessa M. AU - Russell, Ann D. AU - Gaylord, Brian AU - Jahncke, Jaime T2 - Biogeosciences AB - Abstract. The close association between planktic foraminiferal assemblages and local hydrography make foraminifera invaluable proxies for environmental conditions. Modern foraminiferal seasonality is important for interpreting fossil distributions and shell geochemistry as paleoclimate proxies. Understanding this seasonality in an active upwelling area is also critical for anticipating which species may be vulnerable to future changes in upwelling intensity and ocean acidification. Two years (2012–2014) of plankton tows, along with conductivity–temperature–depth profiles and carbonate chemistry measurements taken along the north-central California shelf, offer new insights into the seasonal dynamics of planktic foraminifera in a seasonal coastal upwelling regime. This study finds an upwelling affinity for Neogloboquadrina pachyderma as well as a seasonal and upwelling associated alternation between dominance of N. pachyderma and Neogloboquadrina incompta, consistent with previous observations. Globigerina bulloides, however, shows a strong affinity for non-upwelled waters, in contrast to findings in Southern California where the species is often associated with upwelling. We also find an apparent lunar periodicity in the abundances of all species and document the presence of foraminifera even at very low saturation states of calcite. DA - 2016/9/16/ PY - 2016/9/16/ DO - 10.5194/bg-13-5139-2016 VL - 13 IS - 18 SP - 5139-5150 J2 - Biogeosciences LA - en OP - SN - 1726-4189 UR - http://dx.doi.org/10.5194/bg-13-5139-2016 DB - Crossref ER - TY - MGZN TI - A departmental approach to addressing the problem of sexual harassment and assault in field experiences AU - Robinson, W.A. T2 - In The Trenches DA - 2016/// PY - 2016/// VL - 6 SP - 12–13 ER - TY - CONF TI - Development of the Coupled Northwest Atlantic Prediction System (CNAPS AU - Zambon, J.B. AU - He, R. AU - Warner, J.C. T2 - American Geophysical Union (AGU) Ocean Sciences Meeting C2 - 2016/// CY - New Orleans, LA DA - 2016/// PY - 2016/2/21/ ER - TY - JOUR TI - Superensemble Regional Climate Modeling for the Western United States AU - Mote, Philip W. AU - Allen, Myles R. AU - Jones, Richard G. AU - Li, Sihan AU - Mera, Roberto AU - Rupp, David E. AU - Salahuddin, Ahmed AU - Vickers, Dean T2 - Bulletin of the American Meteorological Society AB - Abstract Computing resources donated by volunteers have generated the first superensemble of regional climate model results, in which the Hadley Centre Regional Model, version 3P (HadRM3P), and Hadley Centre Atmosphere Model, version 3P (HadAM3P), were implemented for the western United States at 25-km resolution. Over 136,000 valid and complete 1-yr runs have been generated to date: about 126,000 for 1960–2009 using observed sea surface temperatures (SSTs) and 10,000 for 2030–49 using projected SSTs from a global model simulation. Ensemble members differ in initial conditions, model physics, and (potentially, for future runs) SSTs. This unprecedented confluence of high spatial resolution and large ensemble size allows high signal-to-noise ratio and more robust estimates of uncertainty. This paper describes the experiment, compares model output with observations, shows select results for climate change simulations, and gives examples of the strength of the large ensemble size. DA - 2016/2/1/ PY - 2016/2/1/ DO - 10.1175/BAMS-D-14-00090.1 VL - 97 IS - 2 SP - 203-215 LA - en OP - SN - 0003-0007 1520-0477 UR - http://dx.doi.org/10.1175/BAMS-D-14-00090.1 DB - Crossref ER - TY - JOUR TI - Impact of synoptic weather patterns and inter-decadal climate variability on air quality in the North China Plain during 1980–2013 AU - Zhang, Yang AU - Ding, Aijun AU - Mao, Huiting AU - Nie, Wei AU - Zhou, Derong AU - Liu, Lixia AU - Huang, Xin AU - Fu, Congbin T2 - Atmospheric Environment AB - Potential relationships between air quality, synoptic weather patterns, and the East Asian Monsoon (EAM) over the North China Plain (NCP) were examined during the time period of 1980–2013 using a weather typing technique and ground-based air pollution index (API) data from three cities: Beijing, Tianjin and Shijiazhuang. Using the Kirchhofer method, circulation patterns during the 34-yr study period were classified into 5 categories, which were further used to understand the quantitative relationship between weather and air quality in NCP. The highest API values were associated with a stagnant weather condition when wide-spread stable conditions controlled most part of NCP, while westerly and southerly wind flowed over the northern and eastern part of this region, resulting in both the regional transport and local build-up of air pollutants. Under the continuous control of this weather pattern, API values were found to increase at a rate of 8.5 per day on average. Based on the qualitative and quantitative analysis, a significant correlation was found between the strength of EAM and inter-annual variability of frequencies of the weather patterns. The strengthening of summer/winter monsoon could increase the frequency of occurrence of cyclone/anticyclone related weather patterns. Time series of climate-induced variability in API over the 34 years were reconstructed based on the quantitative relationship between API and predominant weather patterns during 2001–2010. Significant connections between EAM and reconstructed API were found on both the inter-annual and inter-decadal scales. In winter and summer, strengthening/weakening of EAM, which was generally associated with the change of the representative circulation patterns, could improve/worsen air quality in this region. DA - 2016/1// PY - 2016/1// DO - 10.1016/J.ATMOSENV.2015.05.063 VL - 124 SP - 119-128 J2 - Atmospheric Environment LA - en OP - SN - 1352-2310 UR - http://dx.doi.org/10.1016/J.ATMOSENV.2015.05.063 DB - Crossref KW - Air quality KW - North China Plain KW - Weather typing KW - East Asia Monsoon KW - Climate change ER - TY - BOOK TI - Marine Benthic Dinoflagellates—Unveiling Their Worldwide Biodiversity. Kleine Senckenberg-Reihe, Volume 54. By Mona Hoppenrath, Shauna A. Murray, Nicolas Chomérat, and Takeo Horiguchi. Stuttgart (Germany): E. Schweizerbart’sche Verlagsbuchhandlung. 19.90€ (paper). 276 p.; ill.; taxonomic index. ISBN: 978-3-510-61402-8. 2014. AU - Burkholder, JoAnn AU - Hoppenrath, Mona AU - Murray, Shauna A. AU - Chomerat, Nicolas AU - Horiguchi, Takeo AB - Previous articleNext article No AccessMicrobiologyMarine Benthic Dinoflagellates—Unveiling Their Worldwide Biodiversity. Kleine Senckenberg-Reihe, Volume 54. By Mona Hoppenrath, Shauna A. Murray, Nicolas Chomérat, and Takeo Horiguchi. Stuttgart (Germany): E. Schweizerbart’sche Verlagsbuchhandlung. 19.90€ (paper). 276 p.; ill.; taxonomic index. ISBN: 978-3-510-61402-8. 2014.JoAnn BurkholderJoAnn BurkholderApplied Ecology, North Carolina State University, Raleigh, North Carolina Search for more articles by this author Applied Ecology, North Carolina State University, Raleigh, North CarolinaPDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Quarterly Review of Biology Volume 91, Number 4December 2016 Published in association with Stony Brook University Article DOIhttps://doi.org/10.1086/689525 Views: 17Total views on this site For permission to reuse, please contact [email protected]PDF download Crossref reports no articles citing this article. DA - 2016/12// PY - 2016/12// DO - 10.1086/689525 VL - 91 PB - University of Chicago Press SE - 518–518 UR - http://dx.doi.org/10.1086/689525 ER - TY - JOUR TI - River profile response to normal fault growth and linkage: An example from the Hellenic forearc of south-central Crete, Greece AU - Gallen, Sean F. AU - Wegmann, Karl W. AB - Abstract. Topography is a reflection of the tectonic and geodynamic processes that act to uplift the Earth's surface and the erosional processes that work to return it to base level. Numerous studies have shown that topography is a sensitive recorder or tectonic signals. A quasi-physical understanding of the relationship between river incision and rock uplift has made the analysis of fluvial topography a popular technique for deciphering relative, and some argue absolute, histories of rock uplift. Here we present results from a study of the fluvial topography from south-central Crete demonstrating that river longitudinal profiles indeed record the relative history of uplift, but several other processes make it difficult to recover quantitative uplift histories. Prior research demonstrates that the south-central coastline of Crete is bound by a large (~100 km long) E-W striking composite normal fault system. Marine terraces reveal that it is uplifting between 0.1–1.0 mm yr−1. These studies suggest that two normal fault systems, the offshore Ptolemy and onshore South-Central Crete faults linked together in the recent geologic past (Ca. 0.4–1 Myrs bp). Fault mechanics predicts that when adjacent faults link into a single fault the uplift rate in the linkage zone will increase rapidly. Using river profile analysis we show that rivers in south-central Crete record the relative uplift history of fault growth and linkage, as theory predicts that they should. Calibration of the commonly used stream power incision model shows that the slope exponent, n, is ~ 0.5, contrary to most studies that find n ≥ 1. Analysis of fluvial knickpoints shows that migration distances are not proportional to upstream contributing drainage area, as predicted by the stream power incision model. Maps of the transformed stream distance variable, χ, indicate that drainage basin instability, drainage divide migration and river capture events complicate river profile analysis in south-central Crete. Waterfalls are observed in southern Crete and appear to operate under less efficient and different incision mechanics than assumed by the stream power incision model. Drainage area exchange and waterfall formation are argued to obscure linkages between empirically derived metrics and quasi-physical descriptions of river incision, making is difficult to quantitatively interpret rock uplift histories from river profiles in this setting. Karst hydrology, break down of assumed drainage area-discharge scaling and chemical weathering might also contribute to the failure of the stream power incision model to adequately predict the behavior of the fluvial system in south-central Crete. DA - 2016/11/8/ PY - 2016/11/8/ DO - 10.5194/esurf-2016-52 VL - 11 UR - https://doi.org/10.5194/esurf-2016-52 ER - TY - JOUR TI - Paleotopography and erosion rates in the central Hangay Dome, Mongolia: Landscape evolution since the mid-Miocene AU - Smith, Stephen G. AU - Wegmann, Karl W. AU - Ancuta, Leonard D. AU - Gosse, John C. AU - Hopkins, Chelsea E. T2 - Journal of Asian Earth Sciences AB - Standing over 2 km above the surrounding topography and flanked by orogen-scale strike-slip faults, the Hangay Dome in central Mongolia is characterized by long wavelength high topography, basaltic eruptions spanning 30 million years, and an abundance of flat-topped summit plateaus. However, despite decades of research, the origin and timing of the intraplate Hangay Dome uplift continues to be debated. Using Landsat imagery, GIS, and cosmogenic beryllium-10, we employ geomorphic investigations of (1) paleotopography preserved beneath basalt flows of known age, (2) erosion rates at various temporal scales, and (3) the relative contribution of glacial activity to total erosion to provide insight into the nature of landscape evolution in the Egiin Davaa region of the central Hangay Dome since the middle Miocene. Reconstruction of paleo-valleys cut into Paleozoic basement rock that exhibit a degree of local relief (>600 m) similar to the modern landscape, sluggish mean erosion rates (<45 m Myr−1), and dominance of glacial erosion suggest that there has been no dramatic change in tectonic forcing of the study area since ∼13 Ma, and that high amplitude climate oscillations beginning in the Pliocene have led to an environment influenced primarily by the activity of glaciers. These results provide support for uplift onset during the Oligocene or early Miocene, quantify landscape evolution since the middle Miocene, and underscore the importance of considering geomorphic archives found on Earth’s surface when building models of intra-continental epeirogeny. DA - 2016/// PY - 2016/// DO - http://dx.doi.org/10.1016/j.jseaes.2016.05.013 VL - 125 IS - SP - 37 - 57 UR - http://www.sciencedirect.com/science/article/pii/S1367912016301274 N1 - RN - ER - TY - JOUR TI - Source-to-sink sedimentary systems and global carbon burial: A river runs through it AU - Leithold, Elana L. AU - Blair, Neal E. AU - Wegmann, Karl W. T2 - Earth-Science Reviews AB - Source to sink sedimentary systems are important settings of carbon cycling, serving as sites of carbon transfer between terrestrial and marine reservoirs, and as the primary locations for organic carbon burial on Earth. The age and character of the carbon that is buried at the terminal ends of these systems reflects the sources and transformations of the organic carbon (OC) throughout their linked terrestrial and marine segments. Profound differences are observed between large passive and small active margin systems. Large passive margin systems are characterized by large floodplains and relatively broad shelves where OC has protracted exposure to oxidants. Rapid burial in prograding, subaqueous deltaic clinoforms or bypass to submarine fans, however, leads to high burial efficiency of terrestrial biospheric OC in some passive margin settings. The OC in small active margin systems, in contrast, follows relatively short pathways from headwaters to seabed. This rapid transit, facilitated by the important role of storm-driven transport in such settings, can lead to high OC burial efficiencies. The study of OC sources and transformations in contemporaneous source to sink sedimentary systems informs interpretations about the systems in which OC was buried in the geologic past, their stratigraphic records of environmental change, and their potential to produce petroleum resources. DA - 2016/// PY - 2016/// DO - http://dx.doi.org/10.1016/j.earscirev.2015.10.011 VL - 153 IS - SP - 30 - 42 UR - http://www.sciencedirect.com/science/article/pii/S001282521530057X N1 - Source-to-Sink Systems: Sediment & Solute Transfer on the Earth Surface RN - Source-to-Sink Systems: Sediment & Solute Transfer on the Earth Surface ER - TY - JOUR TI - Storm impact on sea surface temperature and chlorophyll a in the Gulf of Mexico and Sargasso Sea based on daily cloud-free satellite data reconstructions AU - Shropshire, Taylor AU - Li, Yizhen AU - He, Ruoying T2 - Geophysical Research Letters AB - Abstract Upper ocean responses to tropical storms/hurricanes have been extensively studied using satellite observations. However, resolving concurrent sea surface temperature (SST) and chlorophyll a (chl a ) responses along storm tracks remains a major challenge due to extensive cloud coverage in satellite images. Here we produce daily cloud‐free SST and chl a reconstructions based on the Data INterpolating Empirical Orthogonal Function method over a 10 year period (2003–2012) for the Gulf of Mexico and Sargasso Sea regions. Daily reconstructions allow us to characterize and contrast previously obscured subweekly SST and chl a responses to storms in the two main storm‐impacted regions of the Atlantic Ocean. Statistical analyses of daily SST and chl a responses revealed regional differences in the response time as well as the response sensitivity to maximum sustained wind speed and translation speed. This study demonstrates that SST and chl a responses clearly depend on regional ocean conditions and are not as universal as might have been previously suggested. DA - 2016/12/14/ PY - 2016/12/14/ DO - 10.1002/2016GL071178 VL - 43 IS - 23 SP - 12,199-12,207 J2 - Geophys. Res. Lett. LA - en OP - SN - 0094-8276 UR - http://dx.doi.org/10.1002/2016GL071178 DB - Crossref KW - storm KW - sea surface temperature KW - surface chl a KW - northwest Atlantic ocean ER - TY - JOUR TI - Implications for post-comminution processes in subglacial suspended sediment using coupled radiogenic strontium and neodymium isotopes AU - Clinger, Anna E. AU - Aciego, Sarah M. AU - Stevenson, Emily I. AU - Arendt, Carli A. AU - Robbins, Mark J. T2 - Geomorphology AB - Abstract Enhanced physical weathering rates in subglacial systems promote high levels of comminution, transport, and deposition of fine-grained sediment within the subglacial drainage network. The impact of shifts in sediment loads from variations in meltwater flux, and their effects on downstream ecosystems, remains poorly quantified and places a fundamental importance on our ability to characterize subglacial depositional environments. Here, for the first time, we assess the seasonal evolution of the subglacial suspended sediment using coupled radiogenic strontium ( 87 Sr/ 86 Sr) and neodymium ( 143 Nd/ 144 Nd) isotopic ratios with elemental ratios and in situ measurements. Weathering rates in fluvial and riverine systems have been traditionally assessed using radiogenic isotopic tracers: 143 Nd/ 144 Nd ratios relate to the crustal age whereas 87 Sr/ 86 Sr ratios relate to age and preferential mineral dissolution. Thus relative shifts in these ratios will allow us to characterize distinct sediment transport networks. We apply this technique to the Lemon Creek Glacier (LCG), Alaska, USA, and to the Athabasca Glacier (AG), Alberta, CA. At the LCG, the 143 Nd/ 144 Nd values range from e Nd of − 4.6 (0.9) to − 8.7 (0.2), which suggests a poorly mixed sediment flux. However, the greatest period of variability may correlate with the drainage of a supraglacial lake and suggests caution should be exerted in time-scale 143 Nd/ 144 Nd provenance studies that may be affected by climatic disturbances. In contrast, limited variation is observed within the AG 143 Nd/ 144 Nd seasonal record. A consistent, direct relation between the Rb/Sr elemental ratio and the 87 Sr/ 86 Sr ratio proves interesting as it enables us to unravel incongruent weathering trends in the radiogenic Sr record. Correlation between the 87 Sr/ 86 Sr and total discharge suggests that the process is partially controlled by mantling of the bedrock, which can be detected using post-comminution ages. While the subglacial structure may be enabled by the subglacial till beneath the AG, our study supports the use of Sr-Nd as a new proxy in the subglacial environment. DA - 2016/4// PY - 2016/4// DO - 10.1016/J.GEOMORPH.2016.02.006 VL - 259 SP - 134-144 J2 - Geomorphology LA - en OP - SN - 0169-555X UR - http://dx.doi.org/10.1016/J.GEOMORPH.2016.02.006 DB - Crossref KW - Subglacial environment KW - Radiogenic isotopes KW - Suspended sediment KW - Comminution ER - TY - JOUR TI - Insights into combined radiogenic and stable strontium isotopes as tracers for weathering processes in subglacial environments AU - Stevenson, E.I. AU - Aciego, S.M. AU - Chutcharavan, P. AU - Parkinson, I.J. AU - Burton, K.W. AU - Blakowski, M.A. AU - Arendt, C.A. T2 - Chemical Geology AB - This study reports stable and radiogenic strontium isotope behaviour in the dissolved load and suspended sediments from the subglacial outflow of the Lemon Creek glacier (Juneau Ice Field, Alaska) over a single melt season. In situ measurements (discharge, total alkalinity, pH and conductivity) are combined with elemental concentrations, X-ray diffraction (XRD) analysis and radiogenic strontium isotope measurements to interpret the variations observed in stable strontium isotopic ratios. The stable Sr isotope composition (88Sr/86Sr ratio expressed as δ88/86Sr, ‰) of the dissolved load averages 0.31 ± 0.05‰, and is heavier than both the suspended sediment 0.18 ± 0.03‰, as well as local bedrocks ~ 0.20 to 0.26‰. We attribute the enrichment of heavier isotopes in the dissolved load to the uptake of lighter Sr isotopes by secondary weathering minerals, driving the dissolved load to heavier values. X-ray diffraction (XRD) analysis confirms the presence of clays in the suspended sediments and thermodynamic modelling suggests the presence of iron oxy-hydroxide phases. Although it is not possible to completely rule out the effect of dissolution of primary minerals in controlling Sr isotopic compositions of the dissolved load, our data indicate that the extent of secondary mineral formation likely plays a significant role. The preferential weathering of minerals such as biotite (consistent with the mineralogical assemblages found in the suspended sediments), as well as the potential presence of radiogenic calcites from metacarbonates (derived from the Yukon-Tanana terrain), may be driving the small seasonal shifts in 87Sr/86Sr of the dissolved load to more radiogenic compositions, from 87Sr/86Sr(DL) = 0.71048 to 0.710647. Using the combination of stable and radiogenic strontium isotopes to investigate weathering processes shows that radiogenic Sr isotopes provide information regarding weathering of primary phases. While the stable Sr isotope data appear to record information regarding the extent of secondary mineral formation, where secondary minerals incorporate the light isotopes, driving the dissolved load to heavy values. DA - 2016/7// PY - 2016/7// DO - 10.1016/J.CHEMGEO.2016.03.008 VL - 429 SP - 33-43 J2 - Chemical Geology LA - en OP - SN - 0009-2541 UR - http://dx.doi.org/10.1016/J.CHEMGEO.2016.03.008 DB - Crossref KW - Strontium isotopes KW - Stable strontium isotopes KW - Weathering KW - Subglacial environments ER - TY - JOUR TI - Hydrologic controls on radiogenic Sr in meltwater from an alpine glacier system: Athabasca Glacier, Canada AU - Arendt, C.A. AU - Stevenson, E.I. AU - Aciego, S.M. T2 - Applied Geochemistry AB - Filtered subglacial meltwater samples were collected daily during the onset of melt (May) and peak melt (July) over the 2011 melt season at the Athabasca Glacier (Alberta, Canada) and analyzed for strontium-87/strontium-86 (87Sr/86Sr) isotopic composition to infer the evolution of subglacial weathering processes. Both the underlying bedrock composition and subglacial water–rock interaction time are the primary influences on meltwater 87Sr/86Sr. The Athabasca Glacier is situated atop Middle Cambrian carbonate bedrock that also contains silicate minerals. The length of time that subglacial meltwater interacts with the underlying bedrock and substrate is a predominant determining factor in solute concentration. Over the course of the melt season, increasing trends in Ca/K and Ca/Mg correspond to overall decreasing trends in 87Sr/86Sr, which indicate a shift in weathering processes from the presence of silicate weathering to primarily carbonate weathering. Early in the melt season, rates of carbonate dissolution slow as meltwater approaches saturation with respect to calcite and dolomite, corresponding to an increase in silicate weathering that includes Sr-rich silicate minerals, and an increase in meltwater 87Sr/86Sr. However, carbonate minerals are preferentially weathered in unsaturated waters. During the warmest part of a melt season the discharged meltwater is under saturated, causing an increase in carbonate weathering and a decrease in the radiogenic Sr signal. Likewise, larger fraction contributions of meltwater from glacial ice corresponds to lower 87Sr/86Sr values, as the meltwater has lower water–rock interaction times in the subglacial system. These results indicate that although weathering of Sr-containing silicate minerals occurs in carbonate dominated glaciated terrains, the continual contribution of new meltwater permits the carbonate weathering signal to dominate. DA - 2016/6// PY - 2016/6// DO - 10.1016/J.APGEOCHEM.2016.04.002 VL - 69 SP - 42-49 J2 - Applied Geochemistry LA - en OP - SN - 0883-2927 UR - http://dx.doi.org/10.1016/J.APGEOCHEM.2016.04.002 DB - Crossref KW - Radiogenic strontium KW - Oxygen KW - Isotopes KW - Athabasca Glacier KW - Subglacial weathering KW - Meltwater fraction contribution ER - TY - JOUR TI - Detection and attribution of climate extremes in the observed record AU - Easterling, David R. AU - Kunkel, Kenneth E. AU - Wehner, Michael F. AU - Sun, Liqiang T2 - Weather and Climate Extremes AB - We present an overview of practices and challenges related to the detection and attribution of observed changes in climate extremes. Detection is the identification of a statistically significant change in the extreme values of a climate variable over some period of time. Issues in detection discussed include data quality, coverage, and completeness. Attribution takes that detection of a change and uses climate model simulations to evaluate whether a cause can be assigned to that change. Additionally, we discuss a newer field of attribution, event attribution, where individual extreme events are analyzed for the express purpose of assigning some measure of whether that event was directly influenced by anthropogenic forcing of the climate system. DA - 2016/3// PY - 2016/3// DO - 10.1016/J.WACE.2016.01.001 VL - 11 SP - 17-27 J2 - Weather and Climate Extremes LA - en OP - SN - 2212-0947 UR - http://dx.doi.org/10.1016/J.WACE.2016.01.001 DB - Crossref KW - Observed climate change KW - Extremes KW - Detection KW - Attribution ER - TY - JOUR TI - Trends and Extremes in Northern Hemisphere Snow Characteristics AU - Kunkel, Kenneth E. AU - Robinson, David A. AU - Champion, Sarah AU - Yin, Xungang AU - Estilow, Thomas AU - Frankson, Rebekah M. T2 - Current Climate Change Reports AB - Recent studies of snow climatology show a mix of trends but a preponderance of evidence suggest an overall tendency toward decreases in several metrics of snow extremes. The analysis performed herein on maximum seasonal snow depth points to a robust negative trend in this variable for the period of winter 1960/1961–winter 2014/2015. This conclusion is applicable to North America. Maximum snow depth is also mostly decreasing for those European stations analyzed. Research studies show generally negative trends in snow cover extent and snow water equivalent across both North America and Eurasia. These results are mostly, but not fully, consistent with simple hypotheses for the effects of global warming on snow characteristics. DA - 2016/4/8/ PY - 2016/4/8/ DO - 10.1007/S40641-016-0036-8 VL - 2 IS - 2 SP - 65-73 J2 - Curr Clim Change Rep LA - en OP - SN - 2198-6061 UR - http://dx.doi.org/10.1007/S40641-016-0036-8 DB - Crossref KW - Snow KW - Extremes KW - Snow cover KW - Snowfall KW - Snowdepth ER - TY - JOUR TI - Thermodynamic and kinetic behavior of glycerol aerosol AU - Wright, Timothy P. AU - Song, Chen AU - Sears, Stephen AU - Petters, Markus D. T2 - Aerosol Science and Technology AB - Glycerol and propylene glycol mixtures are common carrier solutions in electronic cigarettes. Aerosols produced from these mixtures will evaporate quickly in a dry environment due to their high volatility. In a humid environment, such as the lungs, the kinetics of evaporation and hygroscopic growth determine the evolution of aerosol plume glycerol. Here, we apply a temperature and relative humidity-controlled hygroscopicity/volatility tandem differential mobility analyzer system to study the growth and evaporation kinetics of glycerol aerosol over a wide range of temperature, relative humidity, and residence times. Results show that at dry conditions glycerol aerosols evaporate within seconds at temperatures warmer than 20°C and that the accommodation coefficient of glycerol vapor on dry glycerol particles is 0.8. Under humidified conditions, the mutual depression of vapor pressures of the aqueous glycerol/water solution slows the glycerol evaporation rate consistent with thermodynamic and kinetic model predictions. Model calculations show that water vapor aided condensation of glycerol can occur at high relative humidity for glycerol vapor concentrations that result in glycerol particle evaporation under dry conditions. The combined results will help with constraining computational modules that model the evolution of glycerol-containing aerosols along a prescribed thermodynamic trajectory.Copyright © 2016 American Association for Aerosol Research DA - 2016/10/7/ PY - 2016/10/7/ DO - 10.1080/02786826.2016.1245405 VL - 50 IS - 12 SP - 1385-1396 J2 - Aerosol Science and Technology LA - en OP - SN - 0278-6826 1521-7388 UR - http://dx.doi.org/10.1080/02786826.2016.1245405 DB - Crossref ER - TY - JOUR TI - Coalescence-based assessment of aerosol phase state using dimers prepared through a dual-differential mobility analyzer technique AU - Rothfuss, Nicholas E. AU - Petters, Markus D. T2 - Aerosol Science and Technology AB - Viscosity of atmospheric aerosol spans at least 15 orders of magnitude, from thin liquids to glassy solids, with possible concomitant impact on multiple processes of meteorological and/or climatological concern. Recently there has been interest in aerosol phase assessment techniques based upon dimer coalescence. Theoretical treatment suggests discernible reductions in dimer diameter begin when viscosity ∼108 Pa·s and the dimer is spherical at ∼105 Pa·s for submicron particles, or the middle range of the semisolid regime. A method using nanoparticle dimers synthesized by utilizing differential mobility analyzers of opposite polarity to produce monomers of opposite charge that subsequently undergo electrostatically mediated coagulation has been developed and is detailed in this work. This method was used to assess the aerosol phase state of several atmospherically relevant organic species and inorganic salts at relative humidity (RH) values ranging between 10% and 100%. Ammonium sulfate, monosodium α-ketoglutaric acid, sodium chloride, and sucrose all displayed RH-dependent phase state. These observed viscous transitions occurred at RH values less than existing deliquescence RH data, a result consistent with existing literature reports of RH-induced structural rearrangements. Fully coalesced and fully uncoalesced diameters could be fitted to single values, indicating that the presented technique is absolute. The method was also used to assess the phase state of dry sucrose aerosol at temperatures between 20°C and 70°C. A phase transition was noted at 63.7°C ± 4.4°C, near the glass transition temperature, suggesting the presented method may also be useful for probing phase responses to temperature perturbations.Copyright © 2016 American Association for Aerosol Research DA - 2016/8/5/ PY - 2016/8/5/ DO - 10.1080/02786826.2016.1221050 VL - 50 IS - 12 SP - 1294-1305 J2 - Aerosol Science and Technology LA - en OP - SN - 0278-6826 1521-7388 UR - http://dx.doi.org/10.1080/02786826.2016.1221050 DB - Crossref ER - TY - CHAP TI - Soundscapes and Larval Settlement: Characterizing the Stimulus from a Larval Perspective AU - Lillis, Ashlee AU - Eggleston, David B. AU - Bohnenstiehl, DelWayne R. T2 - The Effects of Noise on Aquatic Life II AB - There is growing evidence that underwater sounds serve as a cue for the larvae of marine organisms to locate suitable settlement habitats; however, the relevant spatiotemporal scales of variability in habitat-related sounds and how this variation scales with larval settlement processes remain largely uncharacterized, particularly in estuarine habitats. Here, we provide an overview of the approaches we have developed to characterize an estuarine soundscape as it relates to larval processes, and a conceptual framework is provided for how habitat-related sounds may influence larval settlement, using oyster reef soundscapes as an example. PY - 2016/// DO - 10.1007/978-1-4939-2981-8_77 SP - 637-645 OP - PB - Springer New York SN - 9781493929801 9781493929818 UR - http://dx.doi.org/10.1007/978-1-4939-2981-8_77 DB - Crossref KW - Estuarine sounds KW - Acoustic cue KW - Drifting hydrophone KW - Bivalve settlement ER - TY - CHAP TI - Soundscapes and Larval Settlement: Larval Bivalve Responses to Habitat-Associated Underwater Sounds AU - Eggleston, David B. AU - Lillis, Ashlee AU - Bohnenstiehl, DelWayne R. T2 - The Effects of Noise on Aquatic Life II AB - We quantified the effects of habitat-associated sounds on the settlement response of two species of bivalves with contrasting habitat preferences: (1) Crassostrea virginicia (oyster), which prefers to settle on other oysters, and (2) Mercenaria mercenaria (clam), which settles on unstructured habitats. Oyster larval settlement in the laboratory was significantly higher when exposed to oyster reef sound compared with either off-reef or no-sound treatments. Clam larval settlement did not vary according to sound treatments. Similar to laboratory results, field experiments showed that oyster larval settlement in "larval housings" suspended above oyster reefs was significantly higher compared with off-reef sites. PY - 2016/// DO - 10.1007/978-1-4939-2981-8_30 SP - 255-263 OP - PB - Springer New York SN - 9781493929801 9781493929818 UR - http://dx.doi.org/10.1007/978-1-4939-2981-8_30 DB - Crossref KW - Clams KW - Estuarine soundscape KW - Habitat-specific sounds KW - Larval settlement KW - Oysters ER - TY - CHAP TI - Causality-Guided Feature Selection AU - Chaudhary, Mandar S. AU - Gonzalez, Doel L. AU - Bello, Gonzalo A. AU - Angus, Michael P. AU - Desai, Dhara AU - Harenberg, Steve AU - Doraiswamy, P. Murali AU - Semazzi, Fredrick H. M. AU - Kumar, Vipin AU - Samatova, Nagiza F. T2 - Advanced Data Mining and Applications AB - Identifying meaningful features that drive a phenomenon (response) of interest in complex systems of interconnected factors is a challenging problem. Causal discovery methods have been previously applied to estimate bounds on causal strengths of factors on a response or to identify meaningful interactions between factors in complex systems, but these approaches have been used only for inferential purposes. In contrast, we posit that interactions between factors with a potential causal association on a given response could be viable candidates not only for hypothesis generation but also for predictive modeling. In this work, we propose a causality-guided feature selection methodology that identifies factors having a potential cause-effect relationship in complex systems, and selects features by clustering them based on their causal strength with respect to the response. To this end, we estimate statistically significant causal effects on the response of factors taking part in potential causal relationships, while addressing associated technical challenges, such as multicollinearity in the data. We validate the proposed methodology for predicting response in five real-world datasets from the domain of climate science and biology. The selected features show predictive skill and consistent performance across different domains. PY - 2016/// DO - 10.1007/978-3-319-49586-6_26 SP - 391-405 OP - PB - Springer International Publishing SN - 9783319495859 9783319495866 UR - http://dx.doi.org/10.1007/978-3-319-49586-6_26 DB - Crossref ER - TY - JOUR TI - Use of plankton-derived vitamin B1 precursors, especially thiazole-related precursor, by key marine picoeukaryotic phytoplankton AU - Paerl, Ryan W AU - Bouget, Francois-Yves AU - Lozano, Jean-Claude AU - Vergé, Valérie AU - Schatt, Philippe AU - Allen, Eric E AU - Palenik, Brian AU - Azam, Farooq T2 - The ISME Journal AB - Several cosmopolitan marine picoeukaryotic phytoplankton are B1 auxotrophs requiring exogenous vitamin B1 or precursor to survive. From genomic evidence, representatives of picoeukaryotic phytoplankton (Ostreococcus and Micromonas spp.) were predicted to use known thiazole and pyrimidine B1 precursors to meet their B1 demands, however, recent culture-based experiments could not confirm this assumption. We hypothesized these phytoplankton strains could grow on precursors alone, but required a thiazole-related precursor other the well-known and extensively tested 4-methyl-5-thiazoleethanol. This hypothesis was tested using bioassays and co-cultures of picoeukaryotic phytoplankton and bacteria. We found that specific B1-synthesizing proteobacteria and phytoplankton are sources of a yet-to-be chemically identified thiazole-related precursor(s) that, along with pyrimidine B1 precursor 4-amino-5-hydroxymethyl-2-methylpyrimidine, can support growth of Ostreococcus spp. (also Micromonas spp.) without B1. We additionally found that the B1-synthesizing plankton do not require contact with picoeukaryotic phytoplankton cells to produce thiazole-related precursor(s). Experiments with wild-type and genetically engineered Ostreococcus lines revealed that the thiazole kinase, ThiM, is required for growth on precursors, and that thiazole-related precursor(s) accumulate to appreciable levels in the euphotic ocean. Overall, our results point to thiazole-related B1 precursors as important micronutrients promoting the survival of abundant phytoplankton influencing surface ocean production and biogeochemical cycling. DA - 2016/12/9/ PY - 2016/12/9/ DO - 10.1038/ISMEJ.2016.145 VL - 11 IS - 3 SP - 753-765 J2 - ISME J LA - en OP - SN - 1751-7362 1751-7370 UR - http://dx.doi.org/10.1038/ISMEJ.2016.145 DB - Crossref ER - TY - JOUR TI - Editorial: Linking Optical and Chemical Properties of Dissolved Organic Matter in Natural Waters AU - Osburn, Christopher L. AU - Bianchi, Thomas S. T2 - Frontiers in Marine Science AB - EDITORIAL article Front. Mar. Sci., 16 November 2016Sec. Marine Biogeochemistry Volume 3 - 2016 | https://doi.org/10.3389/fmars.2016.00223 DA - 2016/11/16/ PY - 2016/11/16/ DO - 10.3389/fmars.2016.00223 VL - 3 J2 - Front. Mar. Sci. OP - SN - 2296-7745 UR - http://dx.doi.org/10.3389/fmars.2016.00223 DB - Crossref KW - CDOM KW - DOC KW - absorbance KW - fluorescence KW - biomarkers KW - stable isotopes KW - photochemistry ER - TY - JOUR TI - Marine Non-Cyanobacterial Diazotrophs: Moving beyond Molecular Detection AU - Bombar, Deniz AU - Paerl, Ryan W. AU - Riemann, Lasse T2 - Trends in Microbiology AB - The nitrogen input through biological N2 fixation is essential for life in vast areas of the global ocean. The belief is that cyanobacteria are the only relevant N2-fixing (diazotrophic) organisms. It has, however, now become evident that non-cyanobacterial diazotrophs, bacteria and archaea with ecologies fundamentally distinct from those of cyanobacteria, are widespread and occasionally fix N2 at significant rates. The documentation of a globally relevant nitrogen input from these diazotrophs would constitute a new paradigm for research on oceanic nitrogen cycling. Here we highlight the need for combining rate measurements and molecular analyses of field samples with cultivation studies in order to clarify the ecology of non-cyanobacteria and their contribution to marine N2 fixation on local and global scales. DA - 2016/11// PY - 2016/11// DO - 10.1016/j.tim.2016.07.002 VL - 24 IS - 11 SP - 916-927 J2 - Trends in Microbiology LA - en OP - SN - 0966-842X UR - http://dx.doi.org/10.1016/j.tim.2016.07.002 DB - Crossref ER - TY - JOUR TI - Linking Heterotrophic Microbial Activities with Particle Characteristics in Waters of the Mississippi River Delta in the Aftermath of Hurricane Isaac AU - Ziervogel, Kai AU - Osburn, Christopher AU - Brym, Adeline AU - Battles, Jessica AU - Joye, Samantha AU - D'souza, Nigel AU - Montoya, Joseph AU - Passow, Uta AU - Arnosti, Carol T2 - Frontiers in Marine Science AB - Riverine runoff often triggers microbial responses in coastal marine environments, including phytoplankton blooms and enhanced bacterial biomass production that drive the transformation of dissolved and particulate organic matter on its way from land to the deep ocean. We measured concentrations and characteristics of particulate organic matter (POM), concentrations of dissolved organic carbon (DOC), and bacterial community abundance and activities in the water column at three sites near the Mississippi River Delta two weeks after Hurricane Isaac made landfall in late August 2012. River plumes had salinities of >30 PSU and high levels of DOC (210-380 µM), resulting from the storm surge that pushed large quantities of marine waters upstream. Relatively high concentrations of phytoplankton POM and low levels of microbial exopolymeric particles (TEP and CSP) suggested that storm-induced riverine discharge triggered the development of phytoplankton blooms that were in their initial stages at the time of sampling. Surface water POM had C/N ratios of 5-7 and strong protein-like fluorescence signals in the base-extracted POM (BEPOM) fraction at the two sites closer to the river mouth (Stns. TE and MSP). Freshly produced POM triggered a twofold increase in heterotrophic bacterial biomass production (3H-leucine incorporation) and a fourfold increase in bacterial peptide hydrolysis (activities of leucine-aminopeptidase). In contrast, elevated DOC concentrations coincided with only moderate bacterial community activity, suggesting that heterotrophic bacterial metabolism near the Mississippi River Delta in the aftermath of Hurricane Isaac was more closely linked with autochthonous primary production. DA - 2016/2/16/ PY - 2016/2/16/ DO - 10.3389/fmars.2016.00008 VL - 3 J2 - Front. Mar. Sci. OP - SN - 2296-7745 UR - http://dx.doi.org/10.3389/fmars.2016.00008 DB - Crossref KW - hydrolytic enzyme activities KW - bacterial protein production KW - base-extracted POM KW - Mississippi River discharge KW - carbon cycle KW - Hurricane Isaac ER - TY - JOUR TI - Optical Proxies for Terrestrial Dissolved Organic Matter in Estuaries and Coastal Waters AU - Osburn, Christopher L. AU - Boyd, Thomas J. AU - Montgomery, Michael T. AU - Bianchi, Thomas S. AU - Coffin, Richard B. AU - Paerl, Hans W. T2 - Frontiers in Marine Science AB - Optical proxies, especially DOM fluorescence, were used to track terrestrial DOM fluxes through estuaries and coastal waters by comparing models developed for several coastal ecosystems. Key to using optical properties is validating and calibrating them with chemical measurements, such as lignin-derived phenols - a proxy to quantify terrestrial DOM. Utilizing parallel factor analysis (PARAFAC), and comparing models statistically using the OpenFluor database (http://www.openfluor.org) we have found common, ubiquitous fluorescing components which correlate most strongly with lignin phenol concentrations in several estuarine and coastal environments. Optical proxies for lignin were computed for the following regions: Mackenzie River Estuary, Atchafalaya River Estuary, Charleston Harbor, Chesapeake Bay, and Neuse River Estuary. The slope of linear regression models relating CDOM absorption at 350 nm (a350) to DOC and to lignin, varied 5 to 10 fold among systems. Where seasonal observations were available from a region, there were distinct seasonal differences in equation parameters for these optical proxies. Despite variability, overall models using single linear regression were developed that related dissolved organic carbon (DOC) concentration to CDOM (DOC = 40×a350+138; R2 = 0.77; N = 130) and lignin (Σ8) to CDOM (Σ8 = 2.03×a350-0.5; R2 = 0.87; N = 130). This wide variability suggested that local or regional optical models should be developed for predicting terrestrial DOM flux into coastal oceans and taken into account when upscaling to remote sensing observations and calibrations. DA - 2016/1/20/ PY - 2016/1/20/ DO - 10.3389/fmars.2015.00127 VL - 2 J2 - Front. Mar. Sci. OP - SN - 2296-7745 UR - http://dx.doi.org/10.3389/fmars.2015.00127 DB - Crossref KW - CDOM absorbance KW - CDOM fluorescence KW - dissolved organic matter (DOM) KW - lignin KW - carbon stable isotopes ER - TY - JOUR TI - The Impact of Incongruous Lake Temperatures on Regional Climate Extremes Downscaled from the CMIP5 Archive Using the WRF Model T2 - Journal of Climate AB - Abstract The impact of incongruous lake temperatures is demonstrated using the Weather Research and Forecasting (WRF) Model to downscale global climate fields. Unrealistic lake temperatures prescribed by the default WRF configuration cause obvious biases near the lakes and also affect predicted extremes hundreds of kilometers from the lakes, especially during winter. Using these default temperatures for the Great Lakes in winter creates a thermally induced wave in the modeled monthly average sea level pressure field, which reaches southern Florida. Differences of more than 0.5 K in monthly average daily maximum 2-m temperature occur along that wave during winter. Noteworthy changes to temperature variability, precipitation, and mesoscale circulation also occur when the default method is used for downscaling. Consequently, improperly setting lake temperatures for downscaling could result in misinterpreting changes in regional climate and adversely affect applications reliant on downscaled data, even in areas remote from the lakes. DA - 2016/1// PY - 2016/1// DO - 10.1175/jcli-d-15-0233.1 UR - http://dx.doi.org/10.1175/jcli-d-15-0233.1 KW - Circulation KW - Dynamics KW - Lake effects KW - Stationary waves KW - Physical Meteorology and Climatology KW - Mass fluxes KW - transport KW - Models and modeling KW - Climate models KW - Mesoscale models KW - Regional models ER - TY - JOUR TI - Co-benefits of global and regional greenhouse gas mitigation for US air quality in 2050 T2 - Atmospheric Chemistry and Physics AB - Policies to mitigate greenhouse gas (GHG) emissions will not only slow climate change, but can also have ancillary benefits of improved air quality. Here we examine the co-benefits of both global and regional GHG mitigation on U.S. air quality in 2050 at fine resolution, using dynamical downscaling methods, building on a previous global co-benefits study (West et al., 2013). The co-benefits for U.S. air quality are quantified via two mechanisms: through reductions in co-emitted air pollutants from the same sources, and by slowing climate change and its influence on air quality, following West et al. (2013). Additionally, we separate the total co-benefits into contributions from domestic GHG mitigation versus mitigation in foreign countries. We use the WRF model to dynamically downscale future global climate to the regional scale, the SMOKE program to directly process global anthropogenic emissions into the regional domain, and we provide dynamical boundary conditions from global simulations to the regional CMAQ model. The total co-benefits of global GHG mitigation from the RCP4.5 scenario compared with its reference are estimated to be higher in the eastern U.S. (ranging from 0.6-1.0 μg m-3) than the west (0-0.4 μg m-3) for PM2.5, with an average of 0.47 μg m-3 over U.S.; for O3, the total co-benefits are more uniform at 2-5 ppb with U.S. average of 3.55 ppb. Comparing the two mechanisms of co-benefits, we find that reductions of co-emitted air pollutants have a much greater influence on both PM2.5 (96% of the total co-benefits) and O3 (89% of the total) than the second co-benefits mechanism via slowing climate change, consistent with West et al. (2013). GHG mitigation from foreign countries contributes more to the U.S. O3 reduction (76% of the total) than that from domestic GHG mitigation only (24%), highlighting the importance of global methane reductions and the intercontinental transport of air pollutants. For PM2.5, the benefits of domestic GHG control are greater (74% of total). Since foreign contributions to co-benefits can be substantial, with foreign O3 benefits much larger than those from domestic reductions, previous studies that focus on local or regional co-benefits may greatly underestimate the total co-benefits of global GHG reductions. We conclude that the U.S. can gain significantly greater domestic air quality co-benefits by engaging with other nations to control GHGs. DA - 2016/8/1/ PY - 2016/8/1/ DO - 10.5194/acp-16-9533-2016 UR - http://dx.doi.org/10.5194/acp-16-9533-2016 ER - TY - CONF TI - Tangible landscape: Cognitively grasping the flowofwater AU - Harmon, B.A. AU - Petrasova, A. AU - Petras, V. AU - Mitasova, H. AU - Meentemeyer, R.K. AB - Complex spatial forms like topography can be challenging to understand, much less intentionally shape, given the heavy cognitive load of visualizing and manipulating 3D form. Spatiotemporal processes like the flow of water over a landscape are even more challenging to understand and intentionally direct as they are dependent upon their context and require the simulation of forces like gravity and momentum. This cognitive work can be offloaded onto computers through 3D geospatial modeling, analysis, and simulation. Interacting with computers, however, can also be challenging, often requiring training and highly abstract thinking. Tangible computing – an emerging paradigm of human-computer interaction in which data is physically manifested so that users can feel it and directly manipulate it – aims to offload this added cognitive work onto the body. We have designed Tangible Landscape, a tangible interface powered by an open source geographic information system (GRASS GIS), so that users can naturally shape topography and interact with simulated processes with their hands in order to make observations, generate and test hypotheses, and make inferences about scientific phenomena in a rapid, iterative process. Conceptually Tangible Landscape couples a malleable physical model with a digital model of a landscape through a continuous cycle of 3D scanning, geospatial modeling, and projection. We ran a flow modeling experiment to test whether tangible interfaces like this can effectively enhance spatial performance by offloading cognitive processes onto computers and our bodies. We used hydrological simulations and statistics to quantitatively assess spatial performance. We found that Tangible Landscape enhanced 3D spatial performance and helped users understand water flow. C2 - 2016/// C3 - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives DA - 2016/// DO - 10.5194/isprsarchives-XLI-B2-647-2016 VL - 41 SP - 647-653 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84981276026&partnerID=MN8TOARS KW - embodied cognition KW - spatial thinking KW - physical processes KW - water flow KW - hydrology KW - tangible user interfaces KW - user experiment KW - 3D ER - TY - CONF TI - Processing UAV and LiDAR point clouds in grass GIS AU - Petras, V. AU - Petrasova, A. AU - Jeziorska, J. AU - Mitasova, H. AB - Today’s methods of acquiring Earth surface data, namely lidar and unmanned aerial vehicle (UAV) imagery, non-selectively collect or generate large amounts of points. Point clouds from different sources vary in their properties such as number of returns, density, or quality. We present a set of tools with applications for different types of points clouds obtained by a lidar scanner, structure from motion technique (SfM), and a low-cost 3D scanner. To take advantage of the vertical structure of multiple return lidar point clouds, we demonstrate tools to process them using 3D raster techniques which allow, for example, the development of custom vegetation classification methods. Dense point clouds obtained from UAV imagery, often containing redundant points, can be decimated using various techniques before further processing. We implemented and compared several decimation techniques in regard to their performance and the final digital surface model (DSM). Finally, we will describe the processing of a point cloud from a low-cost 3D scanner, namely Microsoft Kinect, and its application for interaction with physical models. All the presented tools are open source and integrated in GRASS GIS, a multi-purpose open source GIS with remote sensing capabilities. The tools integrate with other open source projects, specifically Point Data Abstraction Library (PDAL), Point Cloud Library (PCL), and OpenKinect libfreenect2 library to benefit from the open source point cloud ecosystem. The implementation in GRASS GIS ensures long term maintenance and reproducibility by the scientific community but also by the original authors themselves. C2 - 2016/// C3 - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives DA - 2016/// DO - 10.5194/isprsarchives-XLI-B7-945-2016 VL - 41 SP - 945-952 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84979529878&partnerID=MN8TOARS KW - 3D rasters KW - decimation KW - sampling KW - binning KW - LAS KW - PDAL KW - PCL KW - Kinect ER - TY - CONF TI - Open source approachto urban growth simulation AU - Petrasova, A. AU - Petras, V. AU - Van Berkel, D. AU - Harmon, B.A. AU - Mitasova, H. AU - Meentemeyer, R.K. AB - Spatial patterns of land use change due to urbanization and its impact on the landscape are the subject of ongoing research. Urban growth scenario simulation is a powerful tool for exploring these impacts and empowering planners to make informed decisions. We present FUTURES (FUTure Urban – Regional Environment Simulation) – a patch-based, stochastic, multi-level land change modeling framework as a case showing how what was once a closed and inaccessible model benefited from integration with open source GIS.We will describe our motivation for releasing this project as open source and the advantages of integrating it with GRASS GIS, a free, libre and open source GIS and research platform for the geospatial domain. GRASS GIS provides efficient libraries for FUTURES model development as well as standard GIS tools and graphical user interface for model users. Releasing FUTURES as a GRASS GIS add-on simplifies the distribution of FUTURES across all main operating systems and ensures the maintainability of our project in the future. We will describe FUTURES integration into GRASS GIS and demonstrate its usage on a case study in Asheville, North Carolina. The developed dataset and tutorial for this case study enable researchers to experiment with the model, explore its potential or even modify the model for their applications. C2 - 2016/// C3 - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives DA - 2016/// DO - 10.5194/isprsarchives-XLI-B7-953-2016 VL - 41 SP - 953-959 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84979582473&partnerID=MN8TOARS KW - GRASS GIS KW - FUTURES KW - urbanization KW - land change KW - open science KW - simulation ER - TY - JOUR TI - Immersive Tangible Geospatial Modeling AU - Tabrizian, Payam AU - Petrasova, Anna AU - Harmon, Brendan AU - Petras, Vaclav AU - Mitasova, Helena AU - Meentemeyer, Ross T2 - 24TH ACM SIGSPATIAL INTERNATIONAL CONFERENCE ON ADVANCES IN GEOGRAPHIC INFORMATION SYSTEMS (ACM SIGSPATIAL GIS 2016) AB - Tangible Landscape is a tangible interface for geographic information systems (GIS). It interactively couples physical and digital models of a landscape so that users can intuitively explore, model, and analyze geospatial data in a collaborative environment. Conceptually Tangible Landscape lets users hold a GIS in their hands so that they can feel the shape of the topography, naturally sculpt new landforms, and interact with simulations like water flow. Since it only affords a bird's-eye view of the landscape, we coupled it with an immersive virtual environment so that users can virtually walk around the modeled landscape and visualize it at a human-scale. Now as users shape topography, draw trees, define viewpoints, or route a walkthrough, they can see the results on the projection-augmented model, rendered on a display, or rendered on a head-mounted display. In this paper we present the Tangible Landscape Immersive Extension, describe its physical setup and software architecture, and demonstrate its features with a case study. DA - 2016/// PY - 2016/// DO - 10.1145/2996913.2996950 SP - UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85011015621&partnerID=MN8TOARS KW - immersive virtual environments KW - augmented reality KW - tangible user interfaces KW - tangible interaction KW - landscape modeling KW - head mounted display KW - Oculus Rift ER - TY - JOUR TI - The Sensitivity of WRF Downscaled Precipitation in Puerto Rico to Cumulus Parameterization and Interior Grid Nudging AU - Wootten, A. AU - Bowden, J. H. AU - Boyles, R. AU - Terando, A. T2 - JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY AB - Abstract The sensitivity of the precipitation over Puerto Rico that is simulated by the Weather Research and Forecasting (WRF) Model is evaluated using multiple combinations of cumulus parameterization (CP) schemes and interior grid nudging. The NCEP–DOE AMIP-II reanalysis (R-2) is downscaled to 2-km horizontal grid spacing both with convective-permitting simulations (CP active only in the middle and outer domains) and with CP schemes active in all domains. The results generally show lower simulated precipitation amounts than are observed, regardless of WRF configuration, but activating the CP schemes in the inner domain improves the annual cycle, intensity, and placement of rainfall relative to the convective-permitting simulations. Furthermore, the use of interior-grid-nudging techniques in the outer domains improves the placement and intensity of rainfall in the inner domain. Incorporating a CP scheme at convective-permitting scales (<4 km) and grid nudging at non-convective-permitting scales (>4 km) improves the island average correlation of precipitation by 0.05–0.2 and reduces the island average RMSE by up to 40 mm on average over relying on the explicit microphysics at convective-permitting scales with grid nudging. Projected changes in summer precipitation between 2040–42 and 1985–87 using WRF to downscale CCSM4 range from a 2.6-mm average increase to an 81.9-mm average decrease, depending on the choice of CP scheme. The differences are only associated with differences between WRF configurations, which indicates the importance of CP scheme for projected precipitation change as well as historical accuracy. DA - 2016/10// PY - 2016/10// DO - 10.1175/jamc-d-16-0121.1 VL - 55 IS - 10 SP - 2263-2281 SN - 1558-8432 UR - http://dx.doi.org/10.1175/jamc-d-16-0121.1 ER - TY - JOUR TI - Evaluation of a High-Resolution SPI for Monitoring Local Drought Severity AU - Cumbie-Ward, Rebecca V. AU - Boyles, Ryan P. T2 - JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY AB - Abstract A standardized precipitation index (SPI) that uses high-resolution, daily estimates of precipitation from the National Weather Service over the contiguous United States has been developed and is referred to as HRD SPI. There are two different historical distributions computed in the HRD SPI dataset, each with a different combination of normals period (1971–2000 or 1981–2010) and clustering solution of gauge stations. For each historical distribution, the SPI is computed using the NCEP Stage IV and Advanced Hydrologic Prediction Service (AHPS) gridded precipitation datasets for a total of four different HRD SPI products. HRD SPIs are found to correlate strongly with independently produced SPIs over the 10-yr period from 2005 to 2015. The drought-monitoring utility of the HRD SPIs is assessed with case studies of drought in the central and southern United States during 2012 and over the Carolinas during 2007–08. A monthly comparison between HRD SPIs and independently produced SPIs reveals generally strong agreement during both events but weak agreement in areas where radar coverage is poor. For both study regions, HRD SPI is compared with the U.S. Drought Monitor (USDM) to assess the best combination of precipitation input, normals period, and station clustering solution. SPI generated with AHPS precipitation and the 1981–2010 PRISM normals and associated cluster solution is found to best capture the spatial extent and severity of drought conditions indicated by the USDM. This SPI is also able to resolve local variations in drought conditions that are not shown by either the USDM or comparison SPI datasets. DA - 2016/10// PY - 2016/10// DO - 10.1175/jamc-d-16-0106.1 VL - 55 IS - 10 SP - 2247-2262 SN - 1558-8432 ER - TY - CONF TI - Tangible landscape: cognitively grasping the flow of water AU - Harmon, B. A. AU - Petrasova, A. AU - Petras, Vaclav AU - Mitasova, Helena AU - Meentemeyer, K. AB - Abstract. Complex spatial forms like topography can be challenging to understand, much less intentionally shape, given the heavy cognitive load of visualizing and manipulating 3D form. Spatiotemporal processes like the flow of water over a landscape are even more challenging to understand and intentionally direct as they are dependent upon their context and require the simulation of forces like gravity and momentum. This cognitive work can be offloaded onto computers through 3D geospatial modeling, analysis, and simulation. Interacting with computers, however, can also be challenging, often requiring training and highly abstract thinking. Tangible computing – an emerging paradigm of human-computer interaction in which data is physically manifested so that users can feel it and directly manipulate it – aims to offload this added cognitive work onto the body. We have designed Tangible Landscape, a tangible interface powered by an open source geographic information system (GRASS GIS), so that users can naturally shape topography and interact with simulated processes with their hands in order to make observations, generate and test hypotheses, and make inferences about scientific phenomena in a rapid, iterative process. Conceptually Tangible Landscape couples a malleable physical model with a digital model of a landscape through a continuous cycle of 3D scanning, geospatial modeling, and projection. We ran a flow modeling experiment to test whether tangible interfaces like this can effectively enhance spatial performance by offloading cognitive processes onto computers and our bodies. We used hydrological simulations and statistics to quantitatively assess spatial performance. We found that Tangible Landscape enhanced 3D spatial performance and helped users understand water flow. C2 - 2016/// C3 - International archives of the photogrammetry remote sensing and spatial DA - 2016/// DO - 10.5194/isprs-archives-xli-b2-647-2016 VL - 41 SP - 647–653 M1 - B2 ER - TY - JOUR TI - Quantifying an aquifer nitrate budget and future nitrate discharge using field data from streambeds and well nests AU - Gilmore, Troy E. AU - Genereux, David P. AU - Solomon, D. Kip AU - Farrell, Kathleen M. AU - Mitasova, Helena T2 - WATER RESOURCES RESEARCH AB - Abstract Novel groundwater sampling (age, flux, and nitrate) carried out beneath a streambed and in wells was used to estimate (1) the current rate of change of nitrate storage, / dt , in a contaminated unconfined aquifer, and (2) future [ ] FWM (the flow‐weighted mean nitrate concentration in groundwater discharge) and (the nitrate flux from aquifer to stream). Estimates of / dt suggested that at the time of sampling (2013) the nitrate storage in the aquifer was decreasing at an annual rate (mean = −9 mmol/m 2 yr) equal to about one‐tenth the rate of nitrate input by recharge. This is consistent with data showing a slow decrease in the [ ] of groundwater recharge in recent years. Regarding future [ ] FWM and , predictions based on well data show an immediate decrease that becomes more rapid after ∼5 years before leveling out in the early 2040s. Predictions based on streambed data generally show an increase in future [ ] FWM and until the late 2020s, followed by a decrease before leveling out in the 2040s. Differences show the potential value of using information directly from the groundwater—surface water interface to quantify the future impact of groundwater nitrate on surface water quality. The choice of denitrification kinetics was similarly important; compared to zero‐order kinetics, a first‐order rate law levels out estimates of future [ ] FWM and (lower peak, higher minimum) as legacy nitrate is flushed from the aquifer. Major fundamental questions about nonpoint‐source aquifer contamination can be answered without a complex numerical model or long‐term monitoring program. DA - 2016/11// PY - 2016/11// DO - 10.1002/2016wr018976 VL - 52 IS - 11 SP - 9046-9065 SN - 1944-7973 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85005896258&partnerID=MN8TOARS ER - TY - JOUR TI - Influence of pulp suspension ph on the performance of chitosan as a strength agent for hardwood cmp paper AU - Rohi, M. AU - Ramezani, O. AU - Rahmaninia, M. AU - Zabihzadeh, S. M. AU - Hubbe, M. A. T2 - Cellulose Chemistry and Technology DA - 2016/// PY - 2016/// VL - 50 IS - 7-8 SP - 873-878 ER - TY - JOUR TI - Gulf Stream variability and a triggering mechanism of its large meander in the South Atlantic Bight AU - Zeng, Xiangming AU - He, Ruoying T2 - JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS AB - The Gulf Stream (GS) variability has an important impact on coastal circulation, shelf ecosystem, and regional weather and climate systems. Here we focus on the variability of the GS south of Cape Hatteras in the South Atlantic Bight (SAB). Statistical analysis on the 21 year satellite altimetry data reveals that the GS path in the SAB has two patterns: weakly and strongly deflected. The strongly deflected pattern is more likely to occur in winter. Over the last two decades, the largest GS offshore meander occurred in November 2009 to April 2010. Realistic ocean hindcast simulation and adjoint sensitivity analysis are used to investigate the triggering mechanisms for this extreme event. Our analyses show that a net increase of relative vorticity near the Charleston Bump was generated by strong interaction between increased GS velocity and local bathymetry, pushing the GS further offshore by virtue of conserving the potential vorticity. Quantitative vorticity analysis confirms this finding. DA - 2016/11// PY - 2016/11// DO - 10.1002/2016jc012077 VL - 121 IS - 11 SP - 8021-8038 SN - 2169-9291 KW - Gulf Stream variability KW - meander KW - South Atlantic Bight KW - ocean modeling KW - adjoint sensitivity ER - TY - JOUR TI - Fort Fisher, NC Past and Present: A Geospatial Analysis using LiDAR and GIS AU - Starek, Michael J. AU - Harmon, Russell S. AU - Mitasova, Helena T2 - MILITARY GEOSCIENCES AND DESERT WARFARE: PAST LESSONS AND MODERN CHALLENGES AB - Fort Fisher was constructed in 1861–1863 by the Confederacy at the mouth of the Cape Fear River in North Carolina to protect the vital trading routes of the seaport at Wilmington. The largest Confederate fort, Ft. Fisher was constructed as an L-shaped fortification consisting of 30 ft (9 m) thick earthen mounds capable of absorbing the shock of a heavy bombardment. In its prime, this fortification consisted of an approximately 1800 ft (550 m) long land face and a mile-long (1.6 km) sea face bounded by two larger 45 ft (14 m) and 60 ft (18 m) high mounds on the southern end. Today, Ft. Fisher is a mere remnant of its former self, with only about one-tenth of the original structure remaining. The region where the fort was constructed is a highly dynamic section of coastline that has undergone extensive shoreline retreat over the past century, resulting in the loss of the majority of the original fortification. Light detection and ranging (LiDAR) survey data and historical maps were used to generate past and present 3-D digital elevation models (DEMs) for both the terrain and fort. The historical shorelines, aerial imagery, bathymetric data and fort models were then integrated and compared within a geographic information system (GIS) to analyze and to model the evolution of the coastline from past to present. Results provide insight into the geographic advantages behind Ft. Fisher’s original layout for defense of the inlet compared to the present day geomorphology of the region. DA - 2016/// PY - 2016/// DO - 10.1007/978-1-4939-3429-4_7 SP - 95-103 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-85064763153&partnerID=MN8TOARS KW - LiDAR KW - Coastal erosion KW - Civil war KW - Spatial modeling ER - TY - JOUR TI - Expressing and Reasoning about Conflicting Norms in Cybersecurity: Poster AU - Jiang, Jiaming AU - Ajmeri, Nirav AU - Chirkova, Rada Y. AU - Doyle, Jon AU - Singh, Munindar P. T2 - SYMPOSIUM AND BOOTCAMP ON THE SCIENCE OF SECURITY AB - Secure collaboration requires the collaborating parties to apply the right policies for their interaction. We adopt a notion of conditional, directed norms as a way to capture the standards of correctness for a collaboration. How can we handle conflicting norms? We describe an approach based on knowledge of what norm dominates what norm in what situation. Our approach adapts answer-set programming to compute stable sets of norms with respect to their computed conflicts and dominance. It assesses agent compliance with respect to those stable sets. We demonstrate our approach on a healthcare scenario. DA - 2016/// PY - 2016/// DO - 10.1145/2898375.2898395 SP - 63-64 KW - Normative System KW - Dominance Relation KW - Norm ER - TY - JOUR TI - Seismic constraints on caldera dynamics from the 2015 Axial Seamount eruption AU - Wilcock, William S. D. AU - Tolstoy, Maya AU - Waldhauser, Felix AU - Garcia, Charles AU - Tan, Yen Joe AU - Bohnenstiehl, DelWayne R. AU - Caplan-Auerbach, Jacqueline AU - Dziak, Robert P. AU - Arnulf, Adrien F. AU - Mann, M. Everett T2 - SCIENCE AB - Volcano monitoring goes into the deep Axial Seamount is a large and active submarine volcano along the Juan de Fuca midocean ridge off the coast of the western United States. Eruptions in 1998 and 2011 were followed by periods of magma recharge, making it an ideal location to include in the Ocean Observatories Initiative Cabled Array. Wilcock et al. present real-time seismic data from the most recent eruption in April 2015 that allow the tracking of magma before and during eruption. Nooner and Chadwick show that eruptions are predictable on the basis of deformation data. As magma pools underneath it, Axial Seamount inflates and erupts when the inflation hits a threshold. Both studies elucidate the dynamics of submarine volcanoes, which vastly outnumber their aboveground counterparts. Science , this issue p. 1395 , p. 1399 DA - 2016/12/16/ PY - 2016/12/16/ DO - 10.1126/science.aah5563 VL - 354 IS - 6318 SP - 1395-1399 SN - 1095-9203 ER - TY - JOUR TI - Linking silicate weathering to riverine geochemistry-A case study from a mountainous tropical setting in west-central Panama AU - Harmon, Russell S. AU - Woerner, Gerhard AU - Goldsmith, Steven T. AU - Harmon, Brendan A. AU - Gardner, Christopher B. AU - Lyons, W. Berry AU - Ogden, Fred L. AU - Pribil, Michael J. AU - Long, David T. AU - Kern, Zoltan AU - Forizs, Istvan T2 - GEOLOGICAL SOCIETY OF AMERICA BULLETIN AB - Research Article| November 01, 2016 Linking silicate weathering to riverine geochemistry—A case study from a mountainous tropical setting in west-central Panama Russell S. Harmon; Russell S. Harmon † 1Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695, USA2Engineer Research and Development Center, International Research Office, U.S. Army Corps of Engineers, Ruislip, HA4 7HB, UK †russell.s.harmon.civ@mail.mil Search for other works by this author on: GSW Google Scholar Gerhard Wörner; Gerhard Wörner 3Division of Geochemistry, Geoscience Centre, University of Göttingen, 37077 Göttingen, Germany Search for other works by this author on: GSW Google Scholar Steven T. Goldsmith; Steven T. Goldsmith 4Department of Geography and the Environment, Villanova University, Villanova, Pennsylvania 19085, USA Search for other works by this author on: GSW Google Scholar Brendan A. Harmon; Brendan A. Harmon 1Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695, USA Search for other works by this author on: GSW Google Scholar Christopher B. Gardner; Christopher B. Gardner 5School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, USA Search for other works by this author on: GSW Google Scholar W. Berry Lyons; W. Berry Lyons 5School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, USA Search for other works by this author on: GSW Google Scholar Fred L. Ogden; Fred L. Ogden 6Department of Civil & Architectural Engineering, University of Wyoming, Laramie, Wyoming 82071, USA Search for other works by this author on: GSW Google Scholar Michael J. Pribil; Michael J. Pribil 7U.S. Geological Survey, P.O. Box 25046, MS973, Denver, Colorado 80225, USA Search for other works by this author on: GSW Google Scholar David T. Long; David T. Long 8Department of Geological Sciences, Michigan State University, East Lansing, Michigan 48824, USA Search for other works by this author on: GSW Google Scholar Zoltán Kern; Zoltán Kern 9Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Budaörsi út 45, Budapest, H-1112, Hungary Search for other works by this author on: GSW Google Scholar István Fórizs István Fórizs 9Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Budaörsi út 45, Budapest, H-1112, Hungary Search for other works by this author on: GSW Google Scholar Author and Article Information Russell S. Harmon † 1Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695, USA2Engineer Research and Development Center, International Research Office, U.S. Army Corps of Engineers, Ruislip, HA4 7HB, UK Gerhard Wörner 3Division of Geochemistry, Geoscience Centre, University of Göttingen, 37077 Göttingen, Germany Steven T. Goldsmith 4Department of Geography and the Environment, Villanova University, Villanova, Pennsylvania 19085, USA Brendan A. Harmon 1Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695, USA Christopher B. Gardner 5School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, USA W. Berry Lyons 5School of Earth Sciences, The Ohio State University, Columbus, Ohio 43210, USA Fred L. Ogden 6Department of Civil & Architectural Engineering, University of Wyoming, Laramie, Wyoming 82071, USA Michael J. Pribil 7U.S. Geological Survey, P.O. Box 25046, MS973, Denver, Colorado 80225, USA David T. Long 8Department of Geological Sciences, Michigan State University, East Lansing, Michigan 48824, USA Zoltán Kern 9Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Budaörsi út 45, Budapest, H-1112, Hungary István Fórizs 9Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Budaörsi út 45, Budapest, H-1112, Hungary †russell.s.harmon.civ@mail.mil Publisher: Geological Society of America Received: 22 Jul 2015 Revision Received: 11 Apr 2016 Accepted: 12 May 2016 First Online: 23 Jun 2017 Online Issn: 1943-2674 Print Issn: 0016-7606 © 2016 Geological Society of America GSA Bulletin (2016) 128 (11-12): 1780–1812. https://doi.org/10.1130/B31388.1 Article history Received: 22 Jul 2015 Revision Received: 11 Apr 2016 Accepted: 12 May 2016 First Online: 23 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Russell S. Harmon, Gerhard Wörner, Steven T. Goldsmith, Brendan A. Harmon, Christopher B. Gardner, W. Berry Lyons, Fred L. Ogden, Michael J. Pribil, David T. Long, Zoltán Kern, István Fórizs; Linking silicate weathering to riverine geochemistry—A case study from a mountainous tropical setting in west-central Panama. GSA Bulletin 2016;; 128 (11-12): 1780–1812. doi: https://doi.org/10.1130/B31388.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Chemical analyses from 71 watersheds across an ∼450 km transect in west-central Panama provide insight into controls on weathering and rates of chemical denudation and CO2 consumption across an igneous arc terrain in the tropics. Stream and river compositions across this region of Panama are generally dilute, having a total dissolved solute value = 118 ± 91 mg/L, with bicarbonate and silica being the predominant dissolved species. Solute, stable isotope, and radiogenic isotope compositions are consistent with dissolution of igneous rocks present in Panama by meteoric precipitation, with geochemical signatures of rivers largely acquired in their upstream regions. Comparison of a headwater basin with its entire watershed observed considerably more runoff production from the high-elevation upstream portion of the catchment than in its much more spatially extensive downstream region. Rock alteration profiles document that weathering proceeds primarily by dissolution of feldspar and pyroxene, with base cations effectively leached in the following sequence: Na > Ca > Mg > K. Control on water chemistry by bedrock lithology is indicated through a linking of elevated ([Na + K]/[Ca + Mg]) ratios in waters to a high proportion of catchment area silicic bedrock and low ratios to mafic bedrock. Sr-isotope ratios are dominated by basement-derived Sr, with only very minor, if any, contribution from other sources. Cation weathering of Casil + Mgsil + Na + K spans about an order in magnitude, from 3 to 32 tons/km2/yr. Strong positive correlations of chemical denudation and CO2 consumption are observed with precipitation, mean watershed elevation, extent of land surface forest cover, and physical erosion rate. You do not have access to this content, please speak to your institutional administrator if you feel you should have access. DA - 2016/11// PY - 2016/11// DO - 10.1130/b31388.1 VL - 128 IS - 11-12 SP - 1780-1812 SN - 1943-2674 ER - TY - JOUR TI - Spatiotemporal changes in precipitation extremes over Yangtze River basin, China, considering the rainfall shift in the late 1970s AU - Gao, Tao AU - Xie, Lian T2 - GLOBAL AND PLANETARY CHANGE AB - Precipitation extremes are the dominated causes for the formation of severe flood disasters at regional and local scales under the background of global climate change. In the present study, five annual extreme precipitation events, including 1, 7 and 30 day annual maximum rainfall and 95th and 97.5th percentile threshold levels, are analyzed relating to the reference period 1960–2011 from 140 meteorological stations over Yangtze River basin (YRB). A generalized extreme value (GEV) distribution is applied to fit annual and percentile extreme precipitation events at each station with return periods up to 200 years. The entire time period is divided into preclimatic (preceding climatic) period 1960–1980 and aftclimatic (after climatic) period 1981–2011 by considering distinctly abrupt shift of precipitation regime in the late 1970s across YRB. And the Mann-Kendall trend test is adopted to conduct trend analysis during pre- and aftclimatic periods, respectively, for the purpose of exploring possible increasing/decreasing patterns in precipitation extremes. The results indicate that the increasing trends for return values during aftclimatic period change significantly in time and space in terms of different magnitudes of extreme precipitation, while the stations with significantly positive trends are mainly distributed in the vicinity of the mainstream and major tributaries as well as large lakes, this would result in more tremendous flood disasters in the mid-lower reaches of YRB, especially in southeast coastal regions. The increasing/decreasing linear trends based on annual maximum precipitation are also investigated in pre- and aftclimatic periods, respectively, whereas those changes are not significantly similar to the variations of return values during both subperiods. Moreover, spatiotemporal patterns of precipitation extremes become more uneven and unstable in the second half period over YRB. DA - 2016/12// PY - 2016/12// DO - 10.1016/j.gloplacha.2016.10.016 VL - 147 SP - 106-124 SN - 1872-6364 KW - Extreme precipitation events KW - Climate change KW - Generalized extreme value distribution KW - Mann-Kendall trend KW - Yangtze River basin ER - TY - CONF TI - Overland flow analysis using time series of sUAS- derived elevation models AU - Jeziorska, J. AU - Mitasova, Helena AU - Petrasova, A. AU - Petras, Vaclav AU - Divakaran, D. AU - Zajkowski, T. AB - Abstract. With the advent of the innovative techniques for generating high temporal and spatial resolution terrain models from Unmanned Aerial Systems (UAS) imagery, it has become possible to precisely map overland flow patterns. Furthermore, the process has become more affordable and efficient through the coupling of small UAS (sUAS) that are easily deployed with Structure from Motion (SfM) algorithms that can efficiently derive 3D data from RGB imagery captured with consumer grade cameras. We propose applying the robust overland flow algorithm based on the path sampling technique for mapping flow paths in the arable land on a small test site in Raleigh, North Carolina. By comparing a time series of five flights in 2015 with the results of a simulation based on the most recent lidar derived DEM (2013), we show that the sUAS based data is suitable for overland flow predictions and has several advantages over the lidar data. The sUAS based data captures preferential flow along tillage and more accurately represents gullies. Furthermore the simulated water flow patterns over the sUAS based terrain models are consistent throughout the year. When terrain models are reconstructed only from sUAS captured RGB imagery, however, water flow modeling is only appropriate in areas with sparse or no vegetation cover. C2 - 2016/// C3 - International archives of the photogrammetry remote sensing and spatial DA - 2016/// DO - 10.5194/isprs-annals-iii-8-159-2016 VL - 3 SP - 159–166 M1 - 8 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84979525774&partnerID=MN8TOARS ER - TY - JOUR TI - Molecular evidence of keratin and melanosomes in feathers of the Early Cretaceous bird Eoconfuciusornis AU - Pan, Yanhong AU - Zheng, Wenxia AU - Moyer, Alison E. AU - Jingmai K. O'Connor, AU - Wang, Min AU - Zheng, Xiaoting AU - Wang, Xiaoli AU - Schroeter, Elena R. AU - Zhou, Zhonghe AU - Schweitzer, Mary H. T2 - PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA AB - Microbodies associated with feathers of both nonavian dinosaurs and early birds were first identified as bacteria but have been reinterpreted as melanosomes. Whereas melanosomes in modern feathers are always surrounded by and embedded in keratin, melanosomes embedded in keratin in fossils has not been demonstrated. Here we provide multiple independent molecular analyses of both microbodies and the associated matrix recovered from feathers of a new specimen of the basal bird Eoconfuciusornis from the Early Cretaceous Jehol Biota of China. Our work represents the oldest ultrastructural and immunological recognition of avian beta-keratin from an Early Cretaceous (∼130-Ma) bird. We apply immunogold to identify protein epitopes at high resolution, by localizing antibody-antigen complexes to specific fossil ultrastructures. Retention of original keratinous proteins in the matrix surrounding electron-opaque microbodies supports their assignment as melanosomes and adds to the criteria employable to distinguish melanosomes from microbial bodies. Our work sheds new light on molecular preservation within normally labile tissues preserved in fossils. DA - 2016/12/6/ PY - 2016/12/6/ DO - 10.1073/pnas.1617168113 VL - 113 IS - 49 SP - E7900-E7907 SN - 0027-8424 KW - keratinous protein KW - immunogold KW - ChemiSTEM KW - melanosome KW - Early Cretaceous ER - TY - JOUR TI - Microscopic and immunohistochemical analyses of the claw of the nesting dinosaur, Citipati osmolskae AU - Moyer, A. E. AU - Zheng, W. X. AU - Schweitzer, M. H. T2 - Proceedings of the Royal Society of London. Series B DA - 2016/// PY - 2016/// VL - 283 IS - 1842 ER - TY - JOUR TI - CDOM Sources and Photobleaching Control Quantum Yields for Oceanic DMS Photolysis AU - Gali, Marti AU - Kieber, David J. AU - Romera-Castillo, Cristina AU - Kinsey, Joanna D. AU - Devred, Emmanuel AU - Perez, Gonzalo L. AU - Westby, George R. AU - Marrase, Celia AU - Babin, Marcel AU - Levasseur, Maurice AU - Duarte, Carlos M. AU - Agusti, Susana AU - Simo, Rafel T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Photolysis is a major removal pathway for the biogenic gas dimethylsulfide (DMS) in the surface ocean. Here we tested the hypothesis that apparent quantum yields (AQY) for DMS photolysis varied according to the quantity and quality of its photosensitizers, chiefly chromophoric dissolved organic matter (CDOM) and nitrate. AQY compiled from the literature and unpublished studies ranged across 3 orders of magnitude at the 330 nm reference wavelength. The smallest AQY(330) were observed in coastal waters receiving major riverine inputs of terrestrial CDOM (0.06-0.5 m3 (mol quanta)-1). In open-ocean waters, AQY(330) generally ranged between 1 and 10 m3 (mol quanta)-1. The largest AQY(330), up to 34 m3 (mol quanta)-1), were seen in the Southern Ocean potentially associated with upwelling. Despite the large AQY variability, daily photolysis rate constants at the sea surface spanned a smaller range (0.04-3.7 d-1), mainly because of the inverse relationship between CDOM absorption and AQY. Comparison of AQY(330) with CDOM spectral signatures suggests there is an interplay between CDOM origin (terrestrial versus marine) and photobleaching that controls variations in AQYs, with a secondary role for nitrate. Our results can be used for regional or large-scale assessment of DMS photolysis rates in future studies. DA - 2016/12/20/ PY - 2016/12/20/ DO - 10.1021/acs.est.6b04278 VL - 50 IS - 24 SP - 13361-13370 SN - 1520-5851 ER - TY - JOUR TI - A Tube Seepage Meter for In Situ Measurement of Seepage Rate and Groundwater Sampling AU - Solder, John E. AU - Gilmore, Troy E. AU - Genereux, David P. AU - Solomon, D. Kip T2 - GROUNDWATER AB - Abstract We designed and evaluated a “tube seepage meter” for point measurements of vertical seepage rates ( q ), collecting groundwater samples, and estimating vertical hydraulic conductivity ( K ) in streambeds. Laboratory testing in artificial streambeds show that seepage rates from the tube seepage meter agreed well with expected values. Results of field testing of the tube seepage meter in a sandy‐bottom stream with a mean seepage rate of about 0.5 m/day agreed well with Darcian estimates (vertical hydraulic conductivity times head gradient) when averaged over multiple measurements. The uncertainties in q and K were evaluated with a Monte Carlo method and are typically 20% and 60%, respectively, for field data, and depend on the magnitude of the hydraulic gradient and the uncertainty in head measurements. The primary advantages of the tube seepage meter are its small footprint, concurrent and colocated assessments of q and K , and that it can also be configured as a self‐purging groundwater‐sampling device. DA - 2016/// PY - 2016/// DO - 10.1111/gwat.12388 VL - 54 IS - 4 SP - 588-595 SN - 1745-6584 ER - TY - JOUR TI - Partially implicit finite difference scheme for calculating dynamic pressure in a terrain-following coordinate non-hydrostatic ocean model AU - Liu, Zhe AU - Lin, Lei AU - Xie, Lian AU - Gao, Huiwang T2 - OCEAN MODELLING AB - To improve the efficiency of the terrain-following σ-coordinate non-hydrostatic ocean model, a partially implicit finite difference (PIFD) scheme is proposed. By using explicit terms instead of implicit terms to discretize the parts of the vertical dynamic pressure gradient derived from the σ-coordinate transformation, the coefficient matrix of the discrete Poisson equation that the dynamic pressure satisfies can be simplified from 15 diagonals to 7 diagonals. The PIFD scheme is shown to run stably when it is applied to simulate five benchmark cases, namely, a standing wave in a basin, a surface solitary wave, a lock-exchange problem, a periodic wave over a bar and a tidally induced internal wave. Compared with the conventional fully implicit finite difference (FIFD) scheme, the PIFD scheme produces simulation results of equivalent accuracy at only 40–60% of the computational cost. The PIFD scheme demonstrates strong applicability and can be easily implemented in σ-coordinate ocean models. DA - 2016/10// PY - 2016/10// DO - 10.1016/j.ocemod.2016.09.004 VL - 106 SP - 44-57 SN - 1463-5011 KW - Non-hydrostatic ocean model KW - Partially implicit finite difference scheme KW - Terrain-following coordinate KW - Internal wave KW - Surface dispersive wave ER - TY - CONF TI - Monitoring the Gulf Stream and shelf environment in the South Atlantic Bight through integrated autonomous underwater glider observations and data assimilative ocean model predictions AU - He, Ruoying AU - Woods, Wendy AU - Zambon, Joseph B. AU - Xue, Zuo T2 - IEEE AB - Gliders are the state-of-the-art autonomous underwater vehicles (AUV) that can operate unattended for roughly a month-long period in the ocean. Given a forward horizontal speed of 0.25 ms -1 , gliders can cover ~ 25 km per day. They trace sawtooth profiles in the ocean by changing buoyancy, observing subsurface temperature, conductivity, and other water properties versus depth, and at the surface, fix position via Global Positioning System. Onshore team monitor and direct glider trajectories using two-way Iridium satellite communications, which permit near real-time delivery of observations and re-direction of mission/adaptive sampling. NCSU Ocean Observing and Modeling Group group has been running glider surveys in the South Atlantic Bight on a seasonal basis. Active research are being carried out to assimilate glider data along with other coastal ocean observations (satellite SST and SSH, mooring time series, HF Radar surface currents) into high resolution regional ocean model using advanced variational data assimilation schemes, providing a new look at along-shelf and cross-shelf exchanges associated with Gulf Stream dynamics. C2 - 2016/4// C3 - OCEANS 2016 - Shanghai DA - 2016/4// DO - 10.1109/oceansap.2016.7485539 SP - 1–4 PB - IEEE ER - TY - JOUR TI - Modeling the influence of deep water application of dispersants on the surface expression of oil: A sensitivity study AU - Testa, Jeremy M. AU - Adams, E. Eric AU - North, Elizabeth W. AU - He, Ruoying T2 - JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS AB - Abstract Although the effects of chemical dispersants on oil droplet sizes and ascent speeds are well‐known, the fate and transport of dispersed oil droplets of different sizes under varying hydrodynamic conditions can be difficult to assess with observations alone. We used a particle tracking model to evaluate the effect of changes in droplet sizes due to dispersant application on the short‐term transport and surface expression of oil released under conditions similar to those following the 3 June 2010 riser cutting during the Deepwater Horizon event. We used simulated injections of oil droplets of varying size and number under conditions associated with no dispersant application and with dispersant application at 50% and 100% efficiency. Due to larger droplet sizes in the no‐dispersant scenario, all of the simulated oil reached the surface within 7 h, while only 61% and 28% of the oil reached the surface after 12 h in the 50% and 100% dispersant efficiency cases, respectively. The length of the surface slick after 6 h was ∼2 km in the no‐dispersant case whereas there was no surface slick after 6 h in the 100% dispersant case, because the smaller oil droplets which resulted from dispersant application had not yet reached the surface. Model results suggest that the application of dispersants at the well head had the following effects: (1) less oil reached the surface in the 6‐12 h after application, (2) oil had a longer residence time in the water‐column, and (3) oil was more highly influenced by subsurface transport. DA - 2016/8// PY - 2016/8// DO - 10.1002/2015jc011571 VL - 121 IS - 8 SP - 5995-6008 SN - 2169-9291 ER - TY - JOUR TI - Measurements and Analysis of Polycyclic Aromatic Hydrocarbons near a Major Interstate AU - Mikel, Dennis K. AU - Aneja, Viney P. T2 - ATMOSPHERE AB - Polycyclic aromatic hydrocarbons (PAHs) were measured near Interstate 40, just east of Research Triangle Park, North Carolina, USA. The goals of this project were to ascertain whether a sufficient quantity of PAHs could be collected using low flow (16.7 L/minute) over 8-h periods and if so, do investigate how the PAHs correlate to local sources, atmospheric pollutants and meteorology. The 8-h integrated samples were collected on 20 sampling days over a two month period during fall 2014. The samples were collected using low flow (BGI Incorporated PQ200) fine particulate samplers analyzed using gas chromatography-mass spectrometry (GC-MS). Temporal distributions of the PAHs (average mean 9.2 nanogram/cubic meter ±9.0 std) were compared to traffic count, and meteorological and pollutant data collected at the near roadway station. Using the meteorological data (i.e., wind speed and direction vector data), wind roses were created illustrating the local sources of the PAHs. In terms of correlation to atmospheric oxidants, (i.e., ozone, nitrogen dioxide and nitric oxide) wind rose analysis illustrated the morning hours which were predominantly southern winds, while the afternoon hours illustrated southerly and easterly winds, which suggests that the automobile traffic is the main source of PAHs. The nighttime hours wind rose shows winds from the northerly and easterly direction, which are predominantly from the RDU International Airport. Since the wind direction vectors illustrated that the afternoon hours (i.e., 12 p.m. to 8 p.m.) were from the interstate, comparisons were performed on the samples collected in this time period for both the traffic and pollutant data. The comparison of the traffic data showed a correlation with the number of vehicles (>60 feet i.e., heavy duty diesel engine vehicles). In addition, with the ozone, nitrogen dioxide and nitric oxide) there is a significant linear correlation between the sum of the measured PAHs with nitric oxide (NO), nitrogen dioxide (NO2) and ozone (O3) with the R2 values being 0.1, 0.04 and 0.07 respectively. An analysis of variance (ANOVA) statistical regression was performed on the pollutant data versus the measured sum of the PAHs. With the alpha set at 0.05, (α = 0.05) the p-values for O3, NO2 and NO were 0.00613, 0.000496 and 0.000264, respectively, which are significant. In addition, the PAH concentration found in this study compare favorably to other published studies (0.1 to 193.6 ng/m3) both nationally and internationally. DA - 2016/10// PY - 2016/10// DO - 10.3390/atmos7100131 VL - 7 IS - 10 SP - SN - 2073-4433 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84994875690&partnerID=MN8TOARS KW - Polycyclic Aromatic Hydrocarbons KW - PAHs KW - ozone KW - near roadway ER - TY - CONF TI - Gulf stream marine hydrokinetic energy resource characterization off Cape Hatteras, North Carolina USA AU - He, Ruoying AU - Bane, John AU - Muglia, Mike AU - Haines, Sara AU - Lowcher, Caroline AU - Gong, Yanlin AU - Taylor, Patterson AB - The Gulf Stream off North Carolina (NC), USA has current velocities that approach 2 ms-1 and average volume transports of 90 Sv (1 Sv= 106 m3s-1) off of Cape Hatteras, making it the most abundant MHK (Marine Hydrokinetic Energy) resource for the state. Resource availability at a specified location depends primarily on the variability in Gulf Stream position, which is least offshore of Cape Hatteras after the stream exits the Florida Straits. Proximity to land and high current velocities in relatively shallow waters on the shelf slope make this an optimal location to quantify the MHK energy resource for NC. Multi-years of consistent current measurements beginning in August of 2013 from a moored 150 kHz ADCP at an optimal location for energy extraction quantify the available energy resource and its variability, and establish the skill of a regional ocean circulation model in predicting the MHK energy resource. The model agrees well with long term observed current averages and weekly to monthly fluctuations in the currents. Comparisons between the model and ADCP observed currents, and power density demonstrate the significant inter-annual variability in the Gulf Stream power density. C2 - 2016/4// C3 - OCEANS 2016 - Shanghai DA - 2016/4// DO - 10.1109/oceansap.2016.7485538 PB - IEEE ER - TY - JOUR TI - Gas-Tracer Experiment for Evaluating the Fate of Methane in a Coastal Plain Stream: Degassing versus in-Stream Oxidation AU - Heilweil, Victor M. AU - Solomon, D. Kip AU - Darrah, Thomas H. AU - Gilmore, Troy E. AU - Genereux, David P. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Methane emissions from streams and rivers have recently been recognized as an important component of global greenhouse budgets. Stream methane is lost as evasion to the atmosphere or in-stream methane oxidation. Previous studies have quantified evasion and oxidation with point-scale measurements. In this study, dissolved gases (methane, krypton) were injected into a coastal plain stream in North Carolina to quantify stream CH4 losses at the watershed scale. Stream-reach modeling yielded gas transfer and oxidation rate constants of 3.2 ± 0.5 and 0.5 ± 1.5 d–1, respectively, indicating a ratio of about 6:1. The resulting evasion and oxidation rates of 2.9 mmol m–2 d–1 and 1,140 nmol L–1 d–1, respectively, lie within ranges of published values. Similarly, the gas transfer velocity (K600) of 2.1 m d–1 is consistent with other gas tracer studies. This study illustrates the utility of dissolved-gas tracers for evaluating stream methane fluxes. In contrast to point measurements, this approach provides a larger watershed-scale perspective. Further work is needed to quantify the magnitude of these fluxes under varying conditions (e.g., stream temperature, nutrient load, gradient, flow rate) at regional and global scales before reliable bottom-up estimates of methane evasion can be determined at global scales. DA - 2016/10/4/ PY - 2016/10/4/ DO - 10.1021/acs.est.6b02224 VL - 50 IS - 19 SP - 10504-10511 SN - 1520-5851 ER - TY - JOUR TI - Composite Environments of Severe and Nonsevere High-Shear, Low-CAPE Convective Events AU - Sherburn, Keith D. AU - Parker, Matthew D. AU - King, Jessica R. AU - Lackmann, Gary M. T2 - WEATHER AND FORECASTING AB - Abstract Severe convection occurring in environments characterized by large amounts of vertical wind shear and limited instability (high-shear, low-CAPE, or “HSLC,” environments) represents a considerable forecasting and nowcasting challenge. Of particular concern, NWS products associated with HSLC convection have low probability of detection and high false alarm rates. Past studies of HSLC convection have examined features associated with single cases; the present work, through composites of numerous cases, illustrates the attributes of “typical” HSLC severe and nonsevere events and identifies features that discriminate between the two. HSLC severe events across the eastern United States typically occur in moist boundary layers within the warm sector or along the cold front of a strong surface cyclone, while those in the western United States have drier boundary layers and more typically occur in the vicinity of a surface triple point or in an upslope regime. The mean HSLC severe event is shown to exhibit stronger forcing for ascent at all levels than its nonsevere counterpart. The majority of EF1 or greater HSLC tornadoes are shown to occur in the southeastern United States, so this region is subjected to the most detailed statistical analysis. Beyond the documented forecasting skill of environmental lapse rates and low-level shear vector magnitude, it is shown that a proxy for the release of potential instability further enhances skill when attempting to identify potentially severe HSLC events. This enhancement is likely associated with the local, in situ CAPE generation provided by this mechanism. Modified forecast parameters including this proxy show considerably improved spatial focusing of the forecast severe threat when compared to existing metrics. DA - 2016/12// PY - 2016/12// DO - 10.1175/waf-d-16-0086.1 VL - 31 IS - 6 SP - 1899-1927 SN - 1520-0434 ER - TY - JOUR TI - CAF: Core to Core Communication Acceleration Framework AU - Wang, Yipeng AU - Wang, Ren AU - Herdrich, Andrew AU - Tsai, James AU - Solihin, Yan T2 - 2016 INTERNATIONAL CONFERENCE ON PARALLEL ARCHITECTURE AND COMPILATION TECHNIQUES (PACT) AB - As the number of cores in a multicore system increases, core-to-core (C2C) communication is increasingly limiting the performance scaling of workloads that share data frequently. The traditional way cores communicate is by using shared memory space between them. However, shared memory communication fundamentally involves coherence invalidations and cache misses, which cause large performance overheads and incur a high amount of network traffic. Many important workloads incur significant C2C communication and are affected significantly by the costs, including pipelined packet processing which is widely used in software-based networking solutions. In these workloads, threads run on different cores and pass packets from one core to another for different stages of processing using software queues. DA - 2016/// PY - 2016/// DO - 10.1145/2967938.2967954 SP - 351-362 KW - Hardware queue KW - multicore communication KW - hardware accelerator ER - TY - JOUR TI - Utilizing the Kantorovich metric for the validation of optical turbulence predictions AU - Wang, Y. AU - Basu, S. T2 - Optics Letters AB - We propose a novel framework for the estimation of C n 2 in the atmosphere. This framework only requires coarse-resolution temperature and pressure profiles as input. Observations from a field campaign over Hawaii are used for validation. DA - 2016/// PY - 2016/// DO - 10.1364/pcdvtap.2015.pm1c.1 VL - 41 IS - 17 SP - 4008-4011 ER - TY - JOUR TI - Using machine learning to produce near surface soil moisture estimates from deeper in situ records at US Climate Reference Network (USCRN) locations: Analysis and applications to AMSR-E satellite validation AU - Coopersmith, Evan J. AU - Cosh, Michael H. AU - Bell, Jesse E. AU - Boyles, Ryan T2 - ADVANCES IN WATER RESOURCES AB - Surface soil moisture is a critical parameter for understanding the energy flux at the land atmosphere boundary. Weather modeling, climate prediction, and remote sensing validation are some of the applications for surface soil moisture information. The most common in situ measurement for these purposes are sensors that are installed at depths of approximately 5 cm. There are however, sensor technologies and network designs that do not provide an estimate at this depth. If soil moisture estimates at deeper depths could be extrapolated to the near surface, in situ networks providing estimates at other depths would see their values enhanced. Soil moisture sensors from the U.S. Climate Reference Network (USCRN) were used to generate models of 5 cm soil moisture, with 10 cm soil moisture measurements and antecedent precipitation as inputs, via machine learning techniques. Validation was conducted with the available, in situ, 5 cm resources. It was shown that a 5 cm estimate, which was extrapolated from a 10 cm sensor and antecedent local precipitation, produced a root-mean-squared-error (RMSE) of 0.0215 m3/m3. Next, these machine-learning-generated 5 cm estimates were also compared to AMSR-E estimates at these locations. These results were then compared with the performance of the actual in situ readings against the AMSR-E data. The machine learning estimates at 5 cm produced an RMSE of approximately 0.03 m3/m3 when an optimized gain and offset were applied. This is necessary considering the performance of AMSR-E in locations characterized by high vegetation water contents, which are present across North Carolina. Lastly, the application of this extrapolation technique is applied to the ECONet in North Carolina, which provides a 10 cm depth measurement as its shallowest soil moisture estimate. A raw RMSE of 0.028 m3/m3 was achieved, and with a linear gain and offset applied at each ECONet site, an RMSE of 0.013 m3/m3 was possible. DA - 2016/12// PY - 2016/12// DO - 10.1016/j.advwatres.2016.10.007 VL - 98 SP - 122-131 SN - 1872-9657 KW - Soil moisture KW - Remote sensing KW - Modeling KW - USCRN KW - AMSR-E KW - ECONet ER - TY - JOUR TI - Thermal stratification in small arctic lakes of southwest Greenland affected by water transparency and epilimnetic temperatures AU - Saros, Jasmine E. AU - Northington, Robert M. AU - Osburn, Christopher L. AU - Burpee, Benjamin T. AU - John Anderson, Nicholas T2 - Limnology and Oceanography AB - Abstract We assessed which factors control summer epilimnion thickness in arctic lakes of southwest Greenland. A suite of 22 lakes that thermally stratify was measured in the summer of 2013; a sub‐set of eight of the lakes was measured again in 2014, which was a warmer summer than 2013. Regression analysis of the 22 lakes indicated that the 1% attenuation depth for photosynthetically active radiation (PAR) was the strongest single predictor ( R 2 = 0.75) of epilimnion thickness across lakes; the addition of epilimnion temperature to the PAR model explained additional variability ( R 2 = 0.79). The importance of including temperature in the model was apparent in the results of model validation as well as when comparing across years: while the 1% PAR was 0.4–2 m deeper in 2014 compared with 2013, water temperatures were 2–3°C higher, resulting in July epilimnion thicknesses that were equal to or shallower than in 2013. In these lakes with low color dissolved organic carbon (DOC), multiple factors control the 1% PAR, including absorbance at 440 nm ( a 440 ), 380 nm ( a 380 ), and 320 ( a 320 ), chlorophyll a (Chl a ) and DOC concentration. In 2014, when 1% PAR was deeper than in 2013, a 380, Chl a and DOC were lower in six of the eight lakes. Our results reveal that the thermal structure of these arctic lakes is under complex control by air temperatures and factors that affect PAR attenuation, particularly Chl a and DOC quality, suggesting that continued warming in the Arctic will have strong effects on lake stratification. DA - 2016/5/27/ PY - 2016/5/27/ DO - 10.1002/lno.10314 VL - 61 IS - 4 SP - 1530-1542 J2 - Limnol. Oceanogr. LA - en OP - SN - 0024-3590 UR - http://dx.doi.org/10.1002/lno.10314 DB - Crossref ER - TY - JOUR TI - The Time Scales of Variability of Marine Low Clouds AU - Szoeke, Simon P. AU - Verlinden, Kathryn L. AU - Yuter, Sandra E. AU - Mechem, David B. T2 - JOURNAL OF CLIMATE AB - Abstract Multidecade global regressions of inversion strength, vertical velocity, and sea surface temperature (SST) on low cloud amount, from subdaily to multiyear time scales, refute the dominance of seasonal inversion strength on marine low cloud variability. Multiday low cloud variance averaged over the eastern Pacific and Atlantic stratocumulus regions [5 × 10−2 (cloud amount)2] is twice the subdaily variance and 5 times larger than the multimonth variance. The broad multiday band contains most (60%) of the variance, despite strong seasonal (annual) and diurnal spectral peaks. Multiday low cloud amount over the eastern tropical and midlatitude oceans is positively correlated to inversion strength, with a slope of 2%–5% K−1. Anecdotes show multiday low cloud and inversion strength anomalies propagate equatorward from midlatitudes. Previously shown correlations of low clouds to strong inversions and cool SST on monthly and longer time scales in the stratocumulus regions imply positive cloud-radiative feedbacks, with e-folding time scales of 300 days for SST and 14 days for atmospheric boundary layer temperature. On multimonth time scales, removing the effect of SST on low clouds reduces the low cloud amount explained by inversion strength by a factor of 3, but SST has a small effect at other time scales. Contrary to their positive correlation in the stratocumulus cloud decks, low clouds are anticorrelated to inversion strength over most of the tropics on daily and subdaily time scales. DA - 2016/9/15/ PY - 2016/9/15/ DO - 10.1175/jcli-d-15-0460.1 VL - 29 IS - 18 SP - 6463-6481 SN - 1520-0442 ER - TY - JOUR TI - Modeling pCO(2) variability in the Gulf of Mexico AU - Xue, Zuo AU - He, Ruoying AU - Fennel, Katja AU - Cai, Wei-Jun AU - Lohrenz, Steven AU - Huang, Wei-Jen AU - Tian, Hanqin AU - Ren, Wei AU - Zang, Zhengchen T2 - BIOGEOSCIENCES AB - Abstract. A three-dimensional coupled physical–biogeochemical model was used to simulate and examine temporal and spatial variability of sea surface pCO2 in the Gulf of Mexico (GoM). The model was driven by realistic atmospheric forcing, open boundary conditions from a data-assimilative global ocean circulation model, and observed freshwater and terrestrial nutrient and carbon input from major rivers. A 7-year model hindcast (2004–2010) was performed and validated against ship measurements. Model results revealed clear seasonality in surface pCO2 and were used to estimate carbon budgets in the Gulf. Based on the average of model simulations, the GoM was a net CO2 sink with a flux of 1.11 ± 0.84 × 1012 mol C yr−1, which, together with the enormous fluvial inorganic carbon input, was comparable to the inorganic carbon export through the Loop Current. Two model sensitivity experiments were performed: one without biological sources and sinks and the other using river input from the 1904–1910 period as simulated by the Dynamic Land Ecosystem Model (DLEM). It was found that biological uptake was the primary driver making GoM an overall CO2 sink and that the carbon flux in the northern GoM was very susceptible to changes in river forcing. Large uncertainties in model simulations warrant further process-based investigations. DA - 2016/8/8/ PY - 2016/8/8/ DO - 10.5194/bg-13-4359-2016 VL - 13 IS - 15 SP - 4359-4377 SN - 1726-4189 ER - TY - JOUR TI - Measuring landscape-scale spread and persistence of an invaded submerged plant community from airborne remote sensing AU - Santos, Maria J. AU - Khanna, Shruti AU - Hestir, Erin L. AU - Greenberg, Jonathan A. AU - Ustin, Susan L. T2 - ECOLOGICAL APPLICATIONS AB - Processes of spread and patterns of persistence of invasive species affect species and communities in the new environment. Predicting future rates of spread is of great interest for timely management decisions, but this depends on models that rely on understanding the processes of invasion and historic observations of spread and persistence. Unfortunately, the rates of spread and patterns of persistence are difficult to model or directly observe, especially when multiple rates of spread and diverse persistence patterns may be co-occurring over the geographic distribution of the invaded ecosystem. Remote sensing systematically acquires data over large areas at fine spatial and spectral resolutions over multiple time periods that can be used to quantify spread processes and persistence patterns. We used airborne imaging spectroscopy data acquired once a year for 5 years from 2004 to 2008 to map an invaded submerged aquatic vegetation (SAV) community across 2220 km2 of waterways in the Sacramento-San Joaquin River Delta, California, USA, and measured its spread rate and its persistence. Submerged aquatic vegetation covered 13-23 km2 of the waterways (6-11%) every year. Yearly new growth accounted for 40-60% of the SAV area, ~50% of which survived to following year. Spread rates were overall negative and persistence decreased with time. From this dataset, we were able to identify both radial and saltatorial spread of the invaded SAV in the entire extent of the Delta over time. With both decreasing spread rate and persistence, it is possible that over time the invasion of this SAV community could decrease its ecological impact. A landscape-scale approach allows measurements of all invasion fronts and the spatial anisotropies associated with spread processes and persistence patterns, without spatial interpolation, at locations both proximate and distant to the focus of invasion at multiple points in time. DA - 2016/9// PY - 2016/9// DO - 10.1890/15-0615 VL - 26 IS - 6 SP - 1733-1744 SN - 1939-5582 KW - distribution KW - imaging spectrometry KW - invasive species KW - remote sensing KW - spread and persistence KW - submerged aquatic vegetation ER - TY - JOUR TI - Landsat 8: Providing continuity and increased precision for measuring multi-decadal time series of total suspended matter AU - Lymburner, Leo AU - Botha, Elizabeth AU - Hestir, Erin AU - Anstee, Janet AU - Sagar, Stephen AU - Dekker, Arnold AU - Malthus, Tim T2 - REMOTE SENSING OF ENVIRONMENT AB - The water clarity of many inland water bodies is under threat due to intensifying land use pressures in conjunction with changes in water levels that result from increasing demand and climate variability. The recent launch of Landsat 8 coupled with Geoscience Australia's recent reprocessing of the Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM +) archives over the whole of Australia to a consistent surface reflectance product enables sub continental scale spatio-temporal analysis of freshwater optical water quality in support of monitoring and decision making for water management agencies. In this research, we present an objective assessment of the potential of Landsat 5 TM, Landsat 7 ETM + and Landsat 8 Operational Land Imager (OLI) data for monitoring inland water quality dynamics over a number of lakes and reservoirs with a range of optical water types in New South Wales and Queensland, Australia. We used bio-optical modelling to develop sensor-specific total suspended matter (TSM) retrieval algorithms that account for the difference in relative spectral response between Landsat 7 ETM + and Landsat 8 OLI. We were able to compare the suitability of the different sensors for optical water quality measurements using water bodies that fell within Landsat path overlaps where Landsat images of surface reflectance were acquired within 24 h between Landsat 5 TM and Landsat 7 ETM + or Landsat 7 ETM + and Landsat 8 OLI. These water bodies represent a range of hydrological and limnological conditions, and enabled us to assess: 1) the comparability of TSM measurements retrieved from each sensor, and 2) the surface reflectance to image noise characteristics of Landsat 7 ETM + and Landsat 8 OLI. Comparisons of lake surface reflectance and noise equivalent reflectance difference show that the improved radiometric resolution and increased quantization of Landsat 8 OLI relative to Landsat 7 ETM + significantly reduce image noise and spectral heterogeneity, indicating that Landsat 8 OLI data are expected to provide more precise water quality retrievals relative to Landsat 7 ETM +. We found that: 1) the TSM retrievals from the different sensors are highly comparable; 2) Landsat 5 TM overestimated TSM relative to Landsat 7 ETM + by 6.4%; and 3) Landsat 7 ETM + overestimated TSM relative to Landsat 8 OLI by only 1.4%. Retrieved TSM values were highly correlated with independent in situ data acquired within 24 h of satellite overpass (r = 0.99) with a mean average error of 14 mg/L. The results demonstrate that time series analysis of TSM retrievals can be conducted across a wide range of lakes at the sub-continental scale to characterise the multi-decadal TSM dynamics. DA - 2016/11// PY - 2016/11// DO - 10.1016/j.rse.2016.04.011 VL - 185 SP - 108-118 SN - 1879-0704 KW - Total suspended matter KW - Landsat KW - Time series KW - Multi-sensor ER - TY - JOUR TI - Century-long increasing trend and variability of dissolved organic carbon export from the Mississippi River basin driven by natural and anthropogenic forcing AU - Ren, Wei AU - Tian, Hanqin AU - Cai, Wei-Jun AU - Lohrenz, Steven E. AU - Hopkinson, Charles S. AU - Huang, Wei-Jen AU - Yang, Jia AU - Tao, Bo AU - Pan, Shufen AU - He, Ruoying T2 - GLOBAL BIOGEOCHEMICAL CYCLES AB - Abstract There has been considerable debate as to how natural forcing and anthropogenic activities alter the timing and magnitude of the delivery of dissolved organic carbon (DOC) to the coastal ocean, which has ramifications for the ocean carbon budget, land‐ocean interactions, and coastal life. Here we present an analysis of DOC export from the Mississippi River to the Gulf of Mexico during 1901–2010 as influenced by changes in climate, land use and management practices, atmospheric CO 2 , and nitrogen deposition, through the integration of observational data with a coupled hydrologic/biogeochemical land model. Model simulations show that DOC export in the 2000s increased more than 40% since the 1900s. For the recent three decades (1981–2010), however, our simulated DOC export did not show a significant increasing trend, which is consistent with observations by U.S. Geological Survey. Our factorial analyses suggest that land use and land cover change, including land management practices (LMPs: i.e., fertilization, irrigation, tillage, etc.), were the dominant contributors to the century‐scale trend of rising total riverine DOC export, followed by changes in atmospheric CO 2 , nitrogen deposition, and climate. Decadal and interannual variations of DOC export were largely attributed to year‐to‐year climatic variability and extreme flooding events, which have been exacerbated by human activity. LMPs show incremental contributions to DOC increase since the 1960s, indicating the importance of sustainable agricultural practices in coping with future environmental changes such as extreme flooding events. Compared to the observational‐based estimate, the modeled DOC export was 20% higher, while DOC concentrations were slightly lower. Further refinements in model structure and input data sets should enable reductions in uncertainties in our prediction of century‐long trends in DOC. DA - 2016/9// PY - 2016/9// DO - 10.1002/2016gb005395 VL - 30 IS - 9 SP - 1288-1299 SN - 1944-9224 ER - TY - JOUR TI - Widespread effusive volcanism on Mercury likely ended by about 3.5Ga AU - Byrne, Paul K. AU - Ostrach, Lillian R. AU - Fassett, Caleb I. AU - Chapman, Clark R. AU - Denevi, Brett W. AU - Evans, Alexander J. AU - Klimczak, Christian AU - Banks, Maria E. AU - Head, James W. AU - Solomon, Sean C. T2 - GEOPHYSICAL RESEARCH LETTERS AB - Abstract Crater size–frequency analyses have shown that the largest volcanic plains deposits on Mercury were emplaced around 3.7 Ga, as determined with recent model production function chronologies for impact crater formation on that planet. To test the hypothesis that all major smooth plains on Mercury were emplaced by about that time, we determined crater size–frequency distributions for the nine next‐largest deposits, which we interpret also as volcanic. Our crater density measurements are consistent with those of the largest areas of smooth plains on the planet. Model ages based on recent crater production rate estimates for Mercury imply that the main phase of plains volcanism on Mercury had ended by ~3.5 Ga, with only small‐scale volcanism enduring beyond that time. Cessation of widespread effusive volcanism is attributable to interior cooling and contraction of the innermost planet. DA - 2016/7/28/ PY - 2016/7/28/ DO - 10.1002/2016gl069412 VL - 43 IS - 14 SP - 7408-7416 SN - 1944-8007 KW - Mercury KW - volcanism KW - crater size-frequency distributions KW - global contraction KW - impact cratering ER - TY - JOUR TI - Variation in habitat soundscape characteristics influences settlement of a reef-building coral AU - Lillis, Ashlee AU - Bohnenstiehl, DelWayne AU - Peters, Jason W. AU - Eggleston, David T2 - PEERJ AB - Coral populations, and the productive reef ecosystems they support, rely on successful recruitment of reef-building species, beginning with settlement of dispersing larvae into habitat favourable to survival. Many substrate cues have been identified as contributors to coral larval habitat selection; however, the potential for ambient acoustic cues to influence coral settlement responses is unknown. Using in situ settlement chambers that excluded other habitat cues, larval settlement of a dominant Caribbean reef-building coral, Orbicella faveolata, was compared in response to three local soundscapes, with differing acoustic and habitat properties. Differences between reef sites in the number of larvae settled in chambers isolating acoustic cues corresponded to differences in sound levels and reef characteristics, with sounds at the loudest reef generating significantly higher settlement during trials compared to the quietest site (a 29.5 % increase). These results suggest that soundscapes could be an important influence on coral settlement patterns and that acoustic cues associated with reef habitat may be related to larval settlement. This study reports an effect of soundscape variation on larval settlement for a key coral species, and adds to the growing evidence that soundscapes affect marine ecosystems by influencing early life history processes of foundational species. DA - 2016/10/13/ PY - 2016/10/13/ DO - 10.7717/peerj.2557 VL - 4 SP - SN - 2167-8359 KW - Coral KW - Larval settlement KW - Reef soundscape KW - Habitat cue KW - Habitat selection ER - TY - JOUR TI - Metamodels for Ozone: Comparison of Three Estimation Techniques AU - Porter, P. Steven AU - Rao, S. T. AU - Hogrefe, Christian AU - Gego, Edith AU - Mathur, Rohit T2 - AIR POLLUTION MODELING AND ITS APPLICATION XXIV AB - A metamodel for ozone is a mathematical relationship between the inputs and outputs of an air quality modeling experiment, permitting calculation of outputs for scenarios of interest without having to run the model again. In this study we compare three metamodel estimation techniques applied to an 18 year long CMAQ simulation covering the Northeastern US (NEUS). The estimation methods considered here include projection onto latent structures, stochastic kriging and a combination of principal components and stochastic kriging. DA - 2016/// PY - 2016/// DO - 10.1007/978-3-319-24478-5_86 SP - 537-542 ER - TY - JOUR TI - International Workshop on Air Pollution, Climate Change, Human Health, and Extreme Weather AU - Dash, Sushil K. AU - Singh, Mahendra P. AU - Rao, S. Trivikrama T2 - AIR POLLUTION MODELING AND ITS APPLICATION XXIV AB - Despite the substantial progress in addressing air quality problems, air pollution is still a serious concern in the developing and developed countries. There is now scientific consensus that atmospheric loading of greenhouse gases has been contributing to climate change. The 2014 IPCC report reiterated the need to address climate change on a global basis. It is also recognized that atmospheric composition can profoundly influence weather and climate directly by changing the atmospheric radiation budget or indirectly by affecting cloud formation and precipitation. Given the ever increasing computational power and ground and satellite-based observations, it is feasible to conduct observational and modeling investigations to improve our understanding of the role of aerosols on the monsoon dynamics and extreme events under changing climate. To address the above mentioned challenges, a three-day workshop was held during January 12–15, 2015 in Delhi, India bringing together scientists in air quality, weather, and climate fields from India, Europe, Japan, and North America to discuss the current state-of-science, identify research gaps, and prepare a research agenda to help improve our understanding of air quality and climate change interactions, and operationalize atmospheric modeling methods to better forecast the monsoon dynamics. Following the workshop, a small team of scientists from India, USA, Canada, and Europe met for a day to prepare an action plan for implementing recommendations of the workshop. It is envisioned that lead scientists identified from different countries will coordinate this research effort. This paper presents a summary of the recommendations made by the workshop participants and actions being taken at the national and international levels. DA - 2016/// PY - 2016/// DO - 10.1007/978-3-319-24478-5_32 SP - 195-199 ER - TY - JOUR TI - Inherent Uncertainties in Atmospheric Models: Weather and Air Pollution AU - Astitha, Marina AU - Yang, Jaemo AU - Luo, Huiying AU - Rao, S. T. T2 - AIR POLLUTION MODELING AND ITS APPLICATION XXIV AB - It is well known that there are reducible and irreducible uncertainties in both uncoupled and coupled meteorology-atmospheric chemistry models. Reducible (i.e., structural and parametric) uncertainties are attributable to our incomplete or inadequate understanding of the relevant atmospheric processes (e.g. chemical mechanism, PBL evolution, modeling domain, grid resolution, cloud treatment) and errors in model input data (e.g., emissions, boundary conditions). Inherent or irreducible uncertainties stem from our inability to properly characterize the atmosphere with appropriate initial conditions. When the initial state of the atmosphere is unknown, its future state cannot be predicted with great accuracy. There is an emerging need to properly assess these types of modeling uncertainties in order to improve the prediction accuracy of modeling systems. This work focuses on the assessment of inherent uncertainties in atmospheric and air quality modeling systems by estimating the impacts of various options for initial conditions on weather parameters and their consequent effect on atmospheric pollutant concentrations. Support for the modeling efforts is given by data collected from surface measurement networks for the meteorological and air quality parameters. We focus on the changes in atmospheric variables that strongly affect the fate and transport of air pollutants like ozone and aerosols. DA - 2016/// PY - 2016/// DO - 10.1007/978-3-319-24478-5_82 SP - 513-518 ER - TY - JOUR TI - Influence of measurement uncertainties on fractional solubility of iron in mineral aerosols over the oceans AU - Meskhidze, Nicholas AU - Johnson, Matthew S. AU - Hurley, David AU - Dawson, Kyle T2 - AEOLIAN RESEARCH AB - The atmospheric supply of mineral dust iron (Fe) plays a crucial role in the Earth’s biogeochemical cycle and is of specific importance as a micronutrient in the marine environment. Observations show several orders of magnitude variability in the fractional solubility of Fe in mineral dust aerosols, making it hard to assess the role of mineral dust in the global ocean biogeochemical Fe cycle. In this study we compare the operational solubility of mineral dust aerosol Fe associated with the flow-through leaching protocol to the results of the global 3-D chemical transport model GEOS-Chem. According to the protocol, aerosol Fe is defined as soluble by first deionized water leaching of mineral dust through a 0.45 μm pore size membrane followed by acidification and storage of the leachate over a long period of time prior to analysis. To estimate the uncertainty in soluble Fe results introduced by the flow-through leaching protocol, we prescribe an average 50% (range of 30–70%) fractional solubility to sub-0.45 μm sized mineral dust particles that may inadvertently pass the filter and end up in the acidified (at pH ∼ 1.7) leachate for a couple of month period. In the model, the fractional solubility of Fe is either explicitly calculated using a complex mineral aerosol Fe dissolution equations, or prescribed to be 1% and 4% often used by global ocean biogeochemical Fe cycle models to reproduce the broad characteristics of the presently observed ocean dissolved iron distribution. Calculations show that the fractional solubility of Fe derived through the flow-through leaching is higher compared to the model results. The largest differences (∼40%) are predicted to occur farther away from the dust source regions, over the areas where sub-0.45 μm sized mineral dust particles contribute a larger fraction of the total mineral dust mass. This study suggests that different methods used in soluble Fe measurements and inconsistences in the operational definition of filterable Fe in marine environment and soluble Fe in atmospheric aerosols are likely to contribute to the wide range of fractional solubility of aerosol Fe reported in the literature. DA - 2016/9// PY - 2016/9// DO - 10.1016/j.aeolia.2016.07.002 VL - 22 SP - 85-92 SN - 2212-1684 KW - Soluble iron KW - Mineral dust KW - Measurement techniques KW - 3-D chemical transport model ER - TY - JOUR TI - Evaluation of Total Precipitable Water from CRCM4 using the NVAP-MEaSUREs Dataset and ERA-Interim Reanalysis Data AU - Paquin, D. AU - Frigon, A. AU - Kunkel, K. E. T2 - ATMOSPHERE-OCEAN AB - The fourth-generation Canadian Regional Climate Model’s (CRCM4) precipitable water is evaluated and compared with observational data and ERA-Interim reanalysis data over five Canadian basins with simulations driven by ERA-Interim (two) and global climate models (two). Considering the 22 years of data available in the observations, we analyze precipitable water’s behaviour through its annual cycle, its daily distribution, and its annual daily maxima. For the simulations driven by reanalyses, differences in annual daily maximum values and their correlations with observations are examined. In general, the values for precipitable water simulated by CRCM4 are similar to those observed, and the model reproduces both the interannual and inter-basin variabilities. The simulation at 15 km resolution produces higher extreme values than simulations performed at 45 km resolution and higher than the observations taken at coarser resolution (1°), without much influence on the mean behaviour. Some underestimation is found with the simulation driven by the Canadian Centre for Climate Modelling and Analysis Model, version 3, a sign of a cold and dry bias, whereas the run driven by the European Centre Hamburg Model, version 5, is much closer to the observations, pointing to the importance of closely considering the regional–global model combination. Overall, CRCM4's ability to reproduce the major characteristics of observed precipitable water makes it a possible tool for providing precipitable water data that could serve as a basis for probable maximum precipitation and probable maximum flood studies at the basin scale. DA - 2016/12// PY - 2016/12// DO - 10.1080/07055900.2016.1230043 VL - 54 IS - 5 SP - 541-548 SN - 1480-9214 KW - regional climate modelling KW - evaluation KW - precipitable water KW - observations ER - TY - JOUR TI - The demographic consequences of growing older and bigger in oyster populations AU - Moore, Jacob L. AU - Lipcius, Romuald N. AU - Puckett, Brandon AU - Schreiber, Sebastian J. T2 - ECOLOGICAL APPLICATIONS AB - Abstract Structured population models, particularly size‐ or age‐structured, have a long history of informing conservation and natural resource management. While size is often easier to measure than age and is the focus of many management strategies, age‐structure can have important effects on population dynamics that are not captured in size‐only models. However, relatively few studies have included the simultaneous effects of both age‐ and size‐structure. To better understand how population structure, particularly that of age and size, impacts restoration and management decisions, we developed and compared a size‐structured integral projection model (IPM) and an age‐ and size‐structured IPM, using a population of Crassostrea gigas oysters in the northeastern Pacific Ocean. We analyzed sensitivity of model results across values of local retention that give populations decreasing in size to populations increasing in size. We found that age‐ and size‐structured models yielded the best fit to the demographic data and provided more reliable results about long‐term demography. Elasticity analysis showed that population growth rate was most sensitive to changes in the survival of both large (>175 mm shell length) and small (<75 mm shell length) oysters, indicating that a maximum size limit, in addition to a minimum size limit, could be an effective strategy for maintaining a sustainable population. In contrast, the purely size‐structured model did not detect the importance of large individuals. Finally, patterns in stable age and stable size distributions differed between populations decreasing in size due to limited local retention and populations increasing in size due to high local retention. These patterns can be used to determine population status and restoration success. The methodology described here provides general insight into the necessity of including both age‐ and size‐structure into modeling frameworks when using population models to inform restoration and management decisions. DA - 2016/10// PY - 2016/10// DO - 10.1002/eap.1374 VL - 26 IS - 7 SP - 2206-2217 SN - 1939-5582 KW - age-structure KW - Crassostrea gigas KW - demographic modeling KW - integral projection model KW - oyster demography KW - size-frequency distribution KW - size-structure ER - TY - JOUR TI - SAR Observation and Numerical Simulation of Mountain Lee Waves Near Kuril Islands Forced by an Extratropical Cyclone AU - Xu, Qing AU - Li, Xiaofeng AU - Bao, Shaowu AU - Pietrafesa, Leonard J. T2 - IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING AB - Several groups of atmospheric gravity waves (AGWs) were observed on a Sentinel-1A synthetic aperture radar (SAR) image acquired near the Kuril Islands in the Northwest Pacific Ocean on June 1, 2015 during the passage of an extratropical cyclone (ETC). These waves occurred on the lee side of the mountains located on the islands. Both diverging and transverse waves with wavelengths ranging between 20 and 30 km are shown as alternating bright-dark patterns in the SAR image. For the diverging waves, there exists a prominent asymmetry in the wave motions of the two arms. The Moderate Resolution Imaging Spectroradiometer and Landsat 7 Enhanced Thematic Mapper Plus images acquired 5-7 h prior to the Sentinel-1A pass also contain the same groups of AGWs. The mesoscale Weather Research and Forecasting model simulation confirms that the AGWs are lee waves triggered by the airflow over the islands. AGWs are aligned perpendicular to the wind direction and locked on the lee side of the islands. The life span of the waves is about two days, consistent with that of the ETC over the region. The numerical model also successfully reproduces the main characteristics of the lee waves. Simulation results demonstrate that the variation in the wave parameters (i.e., wavelength, amplitude, orientation, wedge angle of the diverging wave, and vertical propagation characteristic) and the wave asymmetry of the diverging wave are mainly caused by the wind and stratification changes. The smaller amplitude of the diverging wave seems to be associated with a smaller Froude number. DA - 2016/12// PY - 2016/12// DO - 10.1109/tgrs.2016.2596678 VL - 54 IS - 12 SP - 7157-7165 SN - 1558-0644 KW - Synthetic aperture radar (SAR) KW - waves KW - wind ER - TY - JOUR TI - PLANNING THE NEXT DECADE OF COORDINATED RESEARCH TO BETTER UNDERSTAND AND SIMULATE MARINE LOW CLOUDS AU - Wood, Robert AU - Jensen, Michael P. AU - Wang, Jian AU - Bretherton, Christopher S. AU - Burrows, Susannah M. AU - Del Genio, Anthony D. AU - Fridlind, Ann M. AU - Ghan, Steven J. AU - Ghate, Virendra P. AU - Kollias, Pavlos AU - Krueger, Steven K. AU - McGraw, Robert L. AU - Miller, Mark A. AU - Painemal, David AU - Russell, Lynn M. AU - Yuter, Sandra E. AU - Zuidema, Paquita T2 - BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY AB - CORRESPONDING AUTHOR: Robert Wood, Department of Atmospheric Sciences, University of Washington, Box 351640, Seattle, WA 98195-1640, E-mail: robwood2@uw.edu DA - 2016/9// PY - 2016/9// DO - 10.1175/bams-d-16-0160.1 VL - 97 IS - 9 SP - 1699-1702 SN - 1520-0477 ER - TY - JOUR TI - Hygroscopic growth and cloud droplet activation of xanthan gum as a proxy for marine hydrogels AU - Dawson, K. W. AU - Petters, M. D. AU - Meskhidze, N. AU - Petters, S. Suda AU - Kreidenweis, S. M. T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Abstract Knowledge of the physical characteristics and chemical composition of marine organic aerosols is needed for the quantification of their effects on cloud microphysical processes and solar radiative transfer. Here we use xanthan gum (XG)—a bacterial biopolymer—as a proxy for marine hydrogels. Measurements were performed for pure XG particles and mixtures of XG with sodium chloride, calcium nitrate, and calcium carbonate. The aerosol hygroscopicity parameter ( κ ) is derived from hygroscopic growth factor measurements ( κ gf ) at variable water activity ( a w ) and from cloud condensation nuclei activation efficiency ( κ ccn ). The Zdanovskii, Stokes, and Robinson (ZSR) hygroscopicity parameter derived for multicomponent systems ( κ mix, sol ) is used to compare measurements of κ gf and κ ccn . Pure XG shows close agreement of κ gf (at a w = 0.9) and κ ccn of 0.09 and 0.10, respectively. Adding salts to the system results in deviations of κ gf (at a w = 0.9) from κ ccn . The measured κ gf and ZSR‐derived hygroscopicity parameter ( κ mix, sol ) values for different solutions show close agreement at a w > 0.9, while κ gf is lower in comparison to κ mix, sol at a w < 0.9. The differences between predicted κ mix, sol and measured κ gf and κ ccn values are explained by the effects of hydration and presence of salt ions on the structure of the polymer networks. Results from this study imply that at supersaturations of 0.1 and 0.5%, the presence of 30% sea salt by mass can reduce the activation diameter of pure primary marine organic aerosols from 257 to 156 nm and from 87 to 53 nm, respectively. DA - 2016/10// PY - 2016/10// DO - 10.1002/2016jd025143 VL - 121 IS - 19 SP - 11803-11818 SN - 2169-8996 KW - aerosol water uptake KW - cloud condensation nuclei KW - aerosol hygroscopicity KW - marine organic aerosol KW - xanthan gum KW - hydrogel ER - TY - JOUR TI - Effects of land abandonment and climate change on soil erosion An example from depopulated agricultural lands in the Sudetes Mts., SW Poland AU - Latocha, Agnieszka AU - Szymanowski, Mariusz AU - Jeziorska, Justyna AU - Stec, Magdalena AU - Roszczewska, Monika T2 - CATENA AB - The aim of the study is to calculate and evaluate the changes in spatial distribution of soil erosion rates related to land use/cover changes and climate changes in the Sudetes Mts. within the last 150 years. Various methods were used, including GIS analysis of historical and contemporary land use/cover and climate data, spatial analysis of soil erosion modeling using RUSLE. Changes in spatial distribution of precipitation sums were estimated based on spatial deterministic-stochastic models (regression-kriging) applied to the measurement data from the entire Sudetes region in both analyzed periods. There was a pronounced increase in the area of forests and grasslands at the expenses of arable grounds due to depopulation and consequent land abandonment. These changes started already in the 1880s but they were intensified after World War II. On average soil erosion in the study area decreased by 76.2% (from 4.03 t ha− 1 y− 1 in the 19th century to present 0.96 t ha− 1 y− 1). However, the changes in erosion are highly diverse locally in the studied region with the maximum decrease of 8–16 t ha− 1 y− 1 on steep and higher slopes, which were transformed from arable grounds to forests and grasslands. While both land use and climate changes took place in the study area, changes in land use/cover have a much larger impact on calculated soil erosion rate than climate change. The abandonment of land and the development of spontaneous succession of vegetation limited soil erosion in a very effective way. The values obtained by RUSLE modeling were compared with other values of soil erosion from various field measurements in the Sudetes Mountains in order to evaluate the model. The measurements were based on the experimental plots and sediments stored within the agricultural terraces and in the water reservoirs of various sizes. While the specific sites show large differences in denudation rates, the mean contemporary erosion calculated from our model (0.06 mm y− 1) corresponds with the average rate of denudation, which was calculated for the entire Sudetes: 0.05–0.01 mm y− 1 (Jahn 1968). DA - 2016/10// PY - 2016/10// DO - 10.1016/j.catena.2016.05.027 VL - 145 SP - 128-141 SN - 1872-6887 KW - Soil erosion KW - Land use/cover changes KW - Climate changes KW - Land abandonment KW - RUSLE KW - Sudetes ER - TY - JOUR TI - Convectively Coupled Kelvin Waves and Tropical Cyclogenesis in a Semi-Lagrangian Framework AU - Schreck, Carl J., III T2 - MONTHLY WEATHER REVIEW AB - Abstract This study examines how convectively coupled Kelvin waves interact with the semi-Lagrangian circulation of easterly waves to modulate tropical cyclogenesis. Recent studies have shown that fewer tropical cyclones form in the three days before passage of the Kelvin wave’s peak convection and more develop in the three days thereafter. Separately, other studies have identified the recirculation of moisture and vorticity within easterly waves using a semi-Lagrangian frame of reference. That framework is achieved by subtracting the easterly wave phase speed from the earth-relative winds. This study combines these recent findings by testing whether the equatorial westerlies from Kelvin waves can help close the semi-Lagrangian circulation. Past studies have shown that Kelvin waves tilt westward with height in the troposphere such that equatorial westerlies build upward from the surface in the days following the convective peak. This study shows that the easterly wave’s semi-Lagrangian closed circulation grows upward as it intersects the Kelvin wave’s westward tilt. The Kelvin wave’s westerly anomalies reach 500 hPa about three days after the convection has passed, which establishes the deep, vertically aligned easterly wave vortex necessary for tropical cyclogenesis. This study focuses on the eastern Pacific, but similar results are found for the North Atlantic. In other basins, the Kelvin wave accentuates the westerlies from the Madden–Julian oscillation and/or the monsoon trough. Given that Kelvin waves often last weeks and circumnavigate the globe, these results may advance long-range tropical cyclogenesis forecasting. DA - 2016/11// PY - 2016/11// DO - 10.1175/mwr-d-16-0237.1 VL - 144 IS - 11 SP - 4131-4139 SN - 1520-0493 ER - TY - JOUR TI - Comparisons of Modeled and Observed Reflectivities and Fall Speeds for Snowfall of Varied Riming Degrees during Winter Storms on Long Island, New York AU - Molthan, Andrew L. AU - Colle, Brian A. AU - Yuter, Sandra E. AU - Stark, David T2 - MONTHLY WEATHER REVIEW AB - Abstract Derived radar reflectivities and fall speeds for four Weather Research and Forecasting (WRF) Model bulk microphysical parameterizations (BMPs) run at 1.33-km grid spacing are compared with ground-based, vertically pointing Ku-band radar, scanning S-band radar, and in situ measurements at Stony Brook, New York. Simulations were partitioned into periods of observed riming degree as determined manually using a stereo microscope and camera during nine winter storms. Simulations were examined to determine whether the selected BMPs captured the effects of varying riming intensities, provided a reasonable match to the vertical structure of radar reflectivity or fall speed, and whether they produced reasonable surface fall speed distributions. Schemes assuming nonspherical mass–diameter relationships yielded reflectivity distributions closer to observed values. All four schemes examined in this study provided a better match to the observed, vertical structure of reflectivity during moderate riming than light riming periods. The comparison of observed and simulated snowfall speeds had mixed results. One BMP produced episodes of excessive cloud water at times, resulting in fall speeds that were too large. However, most schemes had frequent periods of little or no cloud water during moderate riming periods and thus underpredicted the snowfall speeds at lower levels. Short, 1–4-h periods with relatively steady snow conditions were used to compare BMP and observed size and fall speed distributions. These limited data suggest the examined BMPs underpredict fall speeds of cold-type snow habits and underrepresent aggregates larger than 4-mm diameter. DA - 2016/11// PY - 2016/11// DO - 10.1175/mwr-d-15-0397.1 VL - 144 IS - 11 SP - 4327-4347 SN - 1520-0493 ER - TY - JOUR TI - Chamber measurements of high CO2 emissions from a rainforest stream receiving old C-rich regional groundwater AU - Oviedo-Vargas, Diana AU - Dierick, Diego AU - Genereux, David P. AU - Oberbauer, Steven F. T2 - BIOGEOCHEMISTRY AB - Carbon emissions from fluvial systems are a key component of local and regional carbon cycles. We used floating chambers to investigate the CO2 flux from stream water to air ( $${\text{f}}_{{{\text{CO}}_{ 2} }}$$ ) in the Arboleda, a stream in the lowland rainforest of Costa Rica, fed partly by old regional groundwater high in dissolved inorganic carbon (DIC). Drifting and static chambers showed $${\text{f}}_{{{\text{CO}}_{ 2} }}$$ averaging 35.5 and 72.7 μmol C m−2 s−1, respectively, bracketing the previously-published $${\text{f}}_{{{\text{CO}}_{ 2} }}$$ value of 56 μmol C m−2 s−1 obtained using tracer methods in this stream. These values are much higher than most $${\text{f}}_{{{\text{CO}}_{ 2} }}$$ data in the literature and reflect a large flux of deep crustal (non-biogenic) CO2 out of the Arboleda, a flux that does not represent a component of ecosystem respiration. Static chambers appeared to overestimate $${\text{f}}_{{{\text{CO}}_{ 2} }}$$ by creating artificial turbulence, while drifting chambers may have underestimated $${\text{f}}_{{{\text{CO}}_{ 2} }}$$ by under-sampling areas of potentially high gas exchange (e.g., riffles around coarse woody debris obstructions). Both static and drifting chambers revealed high spatial heterogeneity in $${\text{f}}_{{{\text{CO}}_{ 2} }}$$ at the scale of 5–30 m reaches. Some observed temporal trends were localized, e.g., among three reaches with repeated measurements through the wet and dry seasons, (1) only the reach located between the other two showed significantly lower $${\text{f}}_{{{\text{CO}}_{ 2} }}$$ during the dry season, and (2) the highest and lowest $${\text{f}}_{{{\text{CO}}_{ 2} }}$$ were consistently observed in the reaches farthest upstream and downstream, respectively. Streams like the Arboleda receiving significant inputs of high-DIC regional groundwater merit additional study as hotspots for C emissions from terrestrial ecosystems. DA - 2016/10// PY - 2016/10// DO - 10.1007/s10533-016-0243-3 VL - 130 IS - 1-2 SP - 69-83 SN - 1573-515X KW - Stream KW - Carbon dioxide KW - Chamber KW - Emissions KW - Flux KW - Regional groundwater KW - Gas exchange ER - TY - JOUR TI - Bony cranial ornamentation linked to rapid evolution of gigantic theropod dinosaurs AU - Gates, T. A. AU - Organ, C. AU - Zanno, L. E. T2 - Nature Communications DA - 2016/// PY - 2016/// VL - 7 ER - TY - CONF TI - Atmospheric absorption versus deep ultraviolet (pre-)resonance in Raman LIDAR measurements AU - Hallen, H. D. AU - Willitsford, A. H. AU - Neely, R. R. AU - Chadwick, C. T. AU - Philbrick, C. R. C2 - 2016/// C3 - Laser radar technology and applications xxi DA - 2016/// VL - 9832 ER - TY - JOUR TI - Using an artificial neural network approach to estimate surface-layer optical turbulence at Mauna Loa, Hawaii AU - Wang, Yao AU - Basu, Sukanta T2 - OPTICS LETTERS AB - In this Letter, an artificial neural network (ANN) approach is proposed for the estimation of optical turbulence (Cn2) in the atmospheric surface layer. Five routinely available meteorological variables are used as the inputs. Observed Cn2 data near the Mauna Loa Observatory, Hawaii are utilized for validation. The proposed approach has demonstrated its prowess by capturing the temporal evolution of Cn2 remarkably well. More interestingly, this ANN approach is found to outperform a widely used similarity theory-based conventional formulation for all the prevalent atmospheric conditions (including strongly stratified conditions). DA - 2016/5/15/ PY - 2016/5/15/ DO - 10.1364/ol.41.002334 VL - 41 IS - 10 SP - 2334-2337 SN - 1539-4794 ER - TY - JOUR TI - Southern Ocean Overturning Compensation in an Eddy-Resolving Climate Simulation AU - Bishop, Stuart P. AU - Gent, Peter R. AU - Bryan, Frank O. AU - Thompson, Andrew F. AU - Long, Matthew C. AU - Abernathey, Ryan T2 - JOURNAL OF PHYSICAL OCEANOGRAPHY AB - Abstract The Southern Ocean’s Antarctic Circumpolar Current (ACC) and meridional overturning circulation (MOC) response to increasing zonal wind stress is, for the first time, analyzed in a high-resolution (0.1° ocean and 0.25° atmosphere), fully coupled global climate simulation using the Community Earth System Model. Results from a 20-yr wind perturbation experiment, where the Southern Hemisphere zonal wind stress is increased by 50% south of 30°S, show only marginal changes in the mean ACC transport through Drake Passage—an increase of 6% [136–144 Sverdrups (Sv; 1 Sv ≡ 10 6 m 3 s −1 )] in the perturbation experiment compared with the control. However, the upper and lower circulation cells of the MOC do change. The lower cell is more affected than the upper cell with a maximum increase of 64% versus 39%, respectively. Changes in the MOC are directly linked to changes in water mass transformation from shifting surface isopycnals and sea ice melt, giving rise to changes in surface buoyancy forcing. The increase in transport of the lower cell leads to upwelling of warm and salty Circumpolar Deep Water and subsequent melting of sea ice surrounding Antarctica. The MOC is commonly supposed to be the sum of two opposing components: a wind- and transient-eddy overturning cell. Here, the transient-eddy overturning is virtually unchanged and consistent with a large-scale cancellation of localized regions of both enhancement and suppression of eddy kinetic energy along the mean path of the ACC. However, decomposing the time-mean overturning into a time- and zonal-mean component and a standing-eddy component reveals partial compensation between wind-driven and standing-eddy components of the circulation. DA - 2016/5// PY - 2016/5// DO - 10.1175/jpo-d-15-0177.1 VL - 46 IS - 5 SP - 1575-1592 SN - 1520-0485 ER - TY - JOUR TI - Predicting Sources of Dissolved Organic Nitrogen to an Estuary from an Agro-Urban Coastal Watershed AU - Osburn, Christopher L. AU - Handsel, Lauren T. AU - Peierls, Benjamin L. AU - Paerl, Hans W. T2 - Environmental Science & Technology AB - Dissolved organic nitrogen (DON) is the nitrogen (N)-containing component of dissolved organic matter (DOM) and in aquatic ecosystems is part of the biologically reactive nitrogen pool that can degrade water quality in N-sensitive waters. Unlike inorganic N (nitrate and ammonium) DON is comprised of many different molecules of variable reactivity. Few methods exist to track the sources of DON in watersheds. In this study, DOM excitation-emission matrix (EEM) fluorescence of eight discrete DON sources was measured and modeled with parallel factor analysis (PARAFAC) and the resulting model ("FluorMod") was fit to 516 EEMs measured in surface waters from the main stem of the Neuse River and its tributaries, located in eastern North Carolina. PARAFAC components were positively correlated to DON concentration. Principle components analysis (PCA) was used to confirm separation of the eight sources and model validation was achieved by measurement of source samples not included in the model development with an error of <10%. Application of FluorMod to surface waters of streams within the Neuse River Basin showed that while >70% of DON was attributed to natural sources, nonpoint sources, such as soil and poultry litter leachates and street runoff, accounted for the remaining 30%. This result was consistent with changes in land use from urbanized Raleigh metropolitan area to the largely agricultural Southeastern coastal plain. Overall, the predicted fraction of nonpoint DON sources was consistent with previous reports of increased organic N inputs in this river basin, which are suspected of impacting the water quality of its estuary. DA - 2016/7/25/ PY - 2016/7/25/ DO - 10.1021/acs.est.6b00053 VL - 50 IS - 16 SP - 8473-8484 J2 - Environ. Sci. Technol. LA - en OP - SN - 0013-936X 1520-5851 UR - http://dx.doi.org/10.1021/acs.est.6b00053 DB - Crossref ER - TY - JOUR TI - Paleotopography and erosion rates in the central Hangay Dome, Mongolia: Landscape evolution since the mid-Miocene AU - Smith, Stephen G. AU - Wegmann, Karl W. AU - Ancuta, Leonard D. AU - Gosse, John C. AU - Hopkins, Chelsea E. T2 - JOURNAL OF ASIAN EARTH SCIENCES AB - Standing over 2 km above the surrounding topography and flanked by orogen-scale strike-slip faults, the Hangay Dome in central Mongolia is characterized by long wavelength high topography, basaltic eruptions spanning 30 million years, and an abundance of flat-topped summit plateaus. However, despite decades of research, the origin and timing of the intraplate Hangay Dome uplift continues to be debated. Using Landsat imagery, GIS, and cosmogenic beryllium-10, we employ geomorphic investigations of (1) paleotopography preserved beneath basalt flows of known age, (2) erosion rates at various temporal scales, and (3) the relative contribution of glacial activity to total erosion to provide insight into the nature of landscape evolution in the Egiin Davaa region of the central Hangay Dome since the middle Miocene. Reconstruction of paleo-valleys cut into Paleozoic basement rock that exhibit a degree of local relief (>600 m) similar to the modern landscape, sluggish mean erosion rates (<45 m Myr−1), and dominance of glacial erosion suggest that there has been no dramatic change in tectonic forcing of the study area since ∼13 Ma, and that high amplitude climate oscillations beginning in the Pliocene have led to an environment influenced primarily by the activity of glaciers. These results provide support for uplift onset during the Oligocene or early Miocene, quantify landscape evolution since the middle Miocene, and underscore the importance of considering geomorphic archives found on Earth’s surface when building models of intra-continental epeirogeny. DA - 2016/8/1/ PY - 2016/8/1/ DO - 10.1016/j.jseaes.2016.05.013 VL - 125 SP - 37-57 SN - 1878-5786 KW - Hangay Mountains KW - Khangay Mountains KW - Erosion rates KW - Cosmogenic beryllium-10 KW - Paleogeomorphology ER - TY - JOUR TI - Measuring Mass-Based Hygroscopicity of Atmospheric Particles through in Situ Imaging AU - Piens, Dominique S. AU - Kelly, Stephen T. AU - Harder, Tristan H. AU - Petters, Markus D. AU - Rachel E. O'Brien, AU - Wang, Bingbing AU - Teske, Ken AU - Dowell, Pat AU - Laskin, Alexander AU - Gilles, Mary K. T2 - ENVIRONMENTAL SCIENCE & TECHNOLOGY AB - Quantifying how atmospheric particles interact with water vapor is critical for understanding the effects of aerosols on climate. We present a novel method to measure the mass-based hygroscopicity of particles while characterizing their elemental and carbon functional group compositions. Since mass-based hygroscopicity is insensitive to particle geometry, it is advantageous for probing the hygroscopic behavior of atmospheric particles, which can have irregular morphologies. Combining scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX), scanning transmission X-ray microscopy (STXM) analysis, and in situ STXM humidification experiments, this method was validated using laboratory-generated, atmospherically relevant particles. Then, the hygroscopicity and elemental composition of 15 complex atmospheric particles were analyzed by leveraging quantification of C, N, and O from STXM, and complementary elemental quantification from SEM/EDX. We found three types of hygroscopic responses, and correlated high hygroscopicity with Na and Cl content. The mixing state of 158 other particles from the sample broadly agreed with those of the humidified particles, indicating the potential to infer atmospheric hygroscopic behavior from a selected subset of particles. These methods offer unique quantitative capabilities to characterize and correlate the hygroscopicity and chemistry of individual submicrometer atmospheric particles. DA - 2016/5/17/ PY - 2016/5/17/ DO - 10.1021/acs.est.6b00793 VL - 50 IS - 10 SP - 5172-5180 SN - 1520-5851 ER - TY - JOUR TI - Interaction Between Two Distinct Mesoscale Circulations During Summer in the Coastal Region of Eastern USA AU - Sims, Aaron P. AU - Raman, Sethu T2 - BOUNDARY-LAYER METEOROLOGY DA - 2016/7// PY - 2016/7// DO - 10.1007/s10546-015-0125-6 VL - 160 IS - 1 SP - 113-132 SN - 1573-1472 KW - Circulations KW - Coastal Carolinas KW - Convection KW - Sandhills KW - Sea breeze ER - TY - JOUR TI - In-situ falling-head test for hydraulic conductivity: Evaluation in layered sediments of an analysis derived for homogenous sediments AU - Burnette, Matthew C. AU - Genereux, David P. AU - Birgand, Francois T2 - JOURNAL OF HYDROLOGY AB - The hydraulic conductivity (K) of streambeds is a critical variable controlling interaction of groundwater and surface water. The Hvorslev analysis for estimating K from falling-head test data has been widely used since the 1950s, but its performance in layered sandy sediments common in streams and lakes has not previously been examined. Our numerical simulations and laboratory experiments show that the Hvorslev analysis yields accurate K values in both homogenous sediment (for which the analysis was originally derived) and layered deposits with low-K sand over high-K sand. K from the Hvorslev analysis deviated significantly from true K only when two conditions were present together: (1) high-K sand was present over low-K sand, and (2) the bottom of the permeameter in which K was measured was at or very near the interface between high-K and low-K. When this combination of conditions exists, simulation and laboratory sand tank results show that in-situ Hvorslev K underestimates the true K of the sediment within a permeameter, because the falling-head test is affected by low-K sediment outside of (below the bottom of) the permeameter. In simulation results, the maximum underestimation (occurring when the bottom of the permeameter was at the interface of high K over low K) was by a factor of 0.91, 0.59, and 0.12 when the high-K to low-K ratio was 2, 10, and 100, respectively. In laboratory sand tank experiments, the underestimation was by a factor of about 0.83 when the high-K to low-K ratio was 2.3. Also, this underestimation of K by the Hvorslev analysis was about the same whether the underlying low-K layer was 2 cm or 174 cm thick (1% or 87% of the domain thickness). Numerical model simulations were useful in the interpretation of in-situ field K profiles at streambed sites with layering; specifically, scaling the model results to the maximum measured K at the top of the field K profiles helped constrain the likely ratio of high K to low K at field locations with layered heterogeneity. Vertical K values are important in field studies of groundwater–surface water interaction, and the Hvorslev analysis can be a useful tool, even in layered media, when applied carefully. DA - 2016/8// PY - 2016/8// DO - 10.1016/j.jhydrol.2016.05.030 VL - 539 SP - 319-329 SN - 1879-2707 KW - Hydraulic conductivity KW - Permeameter KW - Sediments KW - Streambed KW - Numerical modeling KW - Groundwater-surface water interaction ER - TY - JOUR TI - Changes in future air quality, deposition, and aerosol-cloud interactions under future climate and emission scenarios AU - Glotfelty, Timothy AU - Zhang, Yang AU - Karamchandani, Prakash AU - Streets, David G. T2 - ATMOSPHERIC ENVIRONMENT AB - The prospect of global climate change will have wide scale impacts, such as ecological stress and human health hazards. One aspect of concern is future changes in air quality that will result from changes in both meteorological forcing and air pollutant emissions. In this study, the GU-WRF/Chem model is employed to simulate the impact of changing climate and emissions following the IPCC AR4 SRES A1B scenario. An average of 4 future years (2020, 2030, 2040, and 2050) is compared against an average of 2 current years (2001 and 2010). Under this scenario, by the Mid-21st century global air quality is projected to degrade with a global average increase of 2.5 ppb in the maximum 8-hr O3 level and of 0.3 μg m−3 in 24-hr average PM2.5. However, PM2.5 changes are more regional due to regional variations in primary aerosol emissions and emissions of gaseous precursor for secondary PM2.5. Increasing NOx emissions in this scenario combines with a wetter climate elevating levels of OH, HO2, H2O2, and the nitrate radical and increasing the atmosphere’s near surface oxidation state. This differs from findings under the RCP scenarios that experience declines in OH from reduced NOx emissions, stratospheric recovery of O3, and increases in CH4 and VOCs. Increasing NOx and O3 levels enhances the nitrogen and O3 deposition, indicating potentially enhanced crop damage and ecosystem stress under this scenario. The enhanced global aerosol level results in enhancements in aerosol optical depth, cloud droplet number concentration, and cloud optical thickness. This leads to dimming at the Earth’s surface with a global average reduction in shortwave radiation of 1.2 W m−2. This enhanced dimming leads to a more moderate warming trend and different trends in radiation than those found in NCAR’s CCSM simulation, which does not include the advanced chemistry and aerosol treatment of GU-WRF/Chem and cannot simulate the impacts of changing climate and emissions with the same level of detailed treatments. This study indicates that effective climate mitigation and emission control strategies are needed to prevent future health impact and ecosystem stress. Further, studies that are used to develop these strategies should use fully coupled models with sophisticated chemical and aerosol-interaction treatments that can provide a more realistic representation of the atmosphere. DA - 2016/8// PY - 2016/8// DO - 10.1016/j.atmosenv.2016.05.008 VL - 139 SP - 176-191 SN - 1873-2844 KW - Global climate and emissions change KW - Future air quality KW - Aerosol direct effect KW - Aerosol indirect effects KW - Online-coupled model KW - GU_WRF/Chem ER - TY - JOUR TI - A Lagrangian view of moisture dynamics during DYNAMO AU - Hannah, W. M. AU - Mapes, B. E. AU - Elsaesser, G. S. T2 - Journal of the Atmospheric Sciences DA - 2016/// PY - 2016/// VL - 73 IS - 5 SP - 1967-1985 ER - TY - JOUR TI - Transcriptome Analysis of Scrippsiella trochoidea CCMP 3099 Reveals Physiological Changes Related to Nitrate Depletion AU - Cooper, Joshua T. AU - Sinclair, Geoffrey A. AU - Wawrik, Boris T2 - FRONTIERS IN MICROBIOLOGY AB - Dinoflagellates are a major component of marine phytoplankton and many species are recognized for their ability to produce harmful algal blooms (HABs). Scrippsiella trochoidea is a non-toxic, marine dinoflagellate that can be found in both cold and tropic waters where it is known to produce “red tide” events. Little is known about the genomic makeup of S. trochoidea and a transcriptome study was conducted to shed light on the biochemical and physiological adaptations related to nutrient depletion. Cultures were grown under N and P limiting conditions and transcriptomes were generated via RNAseq technology. De novo assembly reconstructed 107,415 putative transcripts of which only 41% could be annotated. No significant transcriptomic response was observed in response to initial P depletion, however, a strong transcriptional response to N depletion was detected. Among the down-regulated pathways were those for glutamine/glutamate metabolism as well as urea and nitrate/nitrite transporters. Transcripts for ammonia transporters displayed both up- and down-regulation, perhaps related to a shift to higher affinity transporters. Genes for the utilization of DON compounds were up-regulated. These included transcripts for amino acids transporters, polyamine oxidase, and extracellular proteinase and peptidases. N depletion also triggered down regulation of transcripts related to the production of Photosystems I & II and related proteins. These data are consistent with a metabolic strategy that conserves N, while maximizing sustained metabolism by emphasizing the relative contribution of organic N sources. Surprisingly, the transcriptome also contained transcripts potentially related to secondary metabolite production, including a homolog to the Short Isoform Saxitoxin gene (sxtA) from Alexandrium fundyense, which was significantly up-regulated under N-depletion. A total of 113 unique hits to Sxt genes, covering 17 of the 34 genes found in C. raciborskii were detected, indicating that S. trochoidea has previously unrecognized potential for the production of secondary metabolites with potential toxicity. DA - 2016/5/9/ PY - 2016/5/9/ DO - 10.3389/fmicb.2016.00639 VL - 7 SP - SN - 1664-302X KW - transcriptome KW - Scrippsiella trochoidea KW - harmful algae KW - nutrient limitation KW - nitrogen KW - dinoflagellates KW - phytoplankton KW - algal physiology ER - TY - JOUR TI - Three-dimensional modeling of the mixing state of particles over Greater Paris AU - Zhu, Shupeng AU - Sartelet, Karine AU - Zhang, Yang AU - Nenes, Athanasios T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Abstract A size‐composition resolved aerosol model (SCRAM) is coupled to the Polyphemus air quality platform and evaluated over Greater Paris. SCRAM simulates the particle mixing state and solves the aerosol dynamic evolution taking into account the processes of coagulation, condensation/evaporation, and nucleation. Both the size and mass fractions of chemical components of particles are discretized. The performance of SCRAM to model air quality over Greater Paris is evaluated by comparison to PM 2.5 , PM 10 , and Aerosol Optical Depth (AOD) measurements. Because air quality models usually assume that particles are internally mixed, the impact of the mixing state on aerosols formation, composition, optical properties, and their ability to be activated as cloud condensation nuclei (CCN) is investigated. The simulation results show that more than half (up to 80% during rush hours) of black carbon particles are barely mixed at the urban site of Paris, while they are more mixed with organic species at a rural site. The comparisons between the internal‐mixing simulation and the mixing state‐resolved simulation show that the internal‐mixing assumption leads to lower nitrate and higher ammonium concentrations in the particulate phase. Moreover, the internal‐mixing assumption leads to lower single scattering albedo, and the difference of aerosol optical depth caused by the mixing state assumption can be as high as 72.5%. Furthermore, the internal‐mixing assumption leads to lower CCN activation percentage at low supersaturation, but higher CCN activation percentage at high supersaturation. DA - 2016/5/27/ PY - 2016/5/27/ DO - 10.1002/2015jd024241 VL - 121 IS - 10 SP - 5930-5947 SN - 2169-8996 ER - TY - JOUR TI - The dual role of nitrogen supply in controlling the growth and toxicity of cyanobacterial blooms AU - Gobler, Christopher J. AU - Burkholder, JoAnn M. AU - Davis, Timothy W. AU - Harke, Matthew J. AU - Johengen, Tom AU - Stow, Craig A. AU - Waal, Dedmer B. T2 - HARMFUL ALGAE AB - Historically, phosphorus (P) has been considered the primary limiting nutrient for phytoplankton assemblages in freshwater ecosystems. This review, supported by new findings from Lake Erie, highlights recent molecular, laboratory, and field evidence that the growth and toxicity of some non-diazotrophic blooms of cyanobacteria can be controlled by nitrogen (N). Cyanobacteria such as Microcystis possess physiological adaptations that allow them to dominate low-P surface waters, and in temperate lakes, cyanobacterial densities can be controlled by N availability. Beyond total cyanobacterial biomass, N loading has been shown to selectively promote the abundance of Microcystis and Planktothrix strains capable of synthesizing microcystins over strains that do not possess this ability. Among strains of cyanobacteria capable of synthesizing the N-rich microcystins, cellular toxin quotas have been found to depend upon exogenous N supplies. Herein, multi-year observations from western Lake Erie are presented demonstrating that microcystin concentrations peak in parallel with inorganic N, but not orthophosphate, concentrations and are significantly lower (p<0.01) during years of reduced inorganic nitrogen loading and concentrations. Collectively, this information underscores the importance of N as well as P in controlling toxic cyanobacteria blooms. Furthermore, it supports the premise that management actions to reduce P in the absence of concurrent restrictions on N loading may not effectively control the growth and/or toxicity of non-diazotrophic toxic cyanobacteria such as the cosmopolitan, toxin-producing genus, Microcystis. DA - 2016/4// PY - 2016/4// DO - 10.1016/j.hal.2016.01.010 VL - 54 SP - 87-97 SN - 1878-1470 KW - Nitrogen KW - Phosphorus KW - Cyanobacteria KW - Microcystis KW - Diazotrophy KW - Nutrients ER - TY - JOUR TI - The Effect of Submerged Aquatic Vegetation Expansion on a Declining Turbidity Trend in the Sacramento-San Joaquin River Delta AU - Hestir, Erin Lee AU - Schoellhamer, David H. AU - Greenberg, Jonathan AU - Morgan-King, Tara AU - Ustin, Susan L. T2 - ESTUARIES AND COASTS AB - Submerged aquatic vegetation (SAV) has well-documented effects on water clarity. SAV beds can slow water movement and reduce bed shear stress, promoting sedimentation and reducing suspension. However, estuaries have multiple controls on turbidity that make it difficult to determine the effect of SAV on water clarity. In this study, we investigated the effect of primarily invasive SAV expansion on a concomitant decline in turbidity in the Sacramento-San Joaquin River Delta. The objective of this study was to separate the effects of decreasing sediment supply from the watershed from increasing SAV cover to determine the effect of SAV on the declining turbidity trend. SAV cover was determined by airborne hyperspectral remote sensing and turbidity data from long-term monitoring records. The turbidity trends were corrected for the declining sediment supply using suspended-sediment concentration data from a station immediately upstream of the Delta. We found a significant negative trend in turbidity from 1975 to 2008, and when we removed the sediment supply signal from the trend it was still significant and negative, indicating that a factor other than sediment supply was responsible for part of the turbidity decline. Turbidity monitoring stations with high rates of SAV expansion had steeper and more significant turbidity trends than those with low SAV cover. Our findings suggest that SAV is an important (but not sole) factor in the turbidity decline, and we estimate that 21–70 % of the total declining turbidity trend is due to SAV expansion. DA - 2016/7// PY - 2016/7// DO - 10.1007/s12237-015-0055-z VL - 39 IS - 4 SP - 1100-1112 SN - 1559-2731 KW - Submerged aquatic vegetation (SAV) KW - Turbidity KW - Suspended sediment KW - San Francisco Estuary ER - TY - JOUR TI - Sensitivity of simulated chemical concentrations and aerosol-meteorology interactions to aerosol treatments and biogenic organic emissions in WRF/Chem AU - Zhang, Yang AU - He, Jian AU - Zhu, Shuai AU - Gantt, Brett T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Abstract Coupled air quality and climate models can predict aerosol concentrations and properties, as well as aerosol direct and indirect effects that depend on aerosol chemistry and microphysics treatments. In this study, Weather Research and Forecasting with Chemistry (WRF/Chem) simulations are conducted over continental U.S. (CONUS) for January and July 2001 with the same gas‐phase mechanism (CB05) but three aerosol modules (Modal Aerosol Dynamics Model for Europe/Secondary Organic Aerosol Model (MADE/SORGAM), Model for Simulating Aerosol Interactions and Chemistry (MOSAIC), and Model of Aerosol Dynamics, Reaction, Ionization and Dissolution (MADRID)) to examine the impacts of aerosol treatments on predictions of aerosols and their effects on cloud properties and radiation. The simulations with the three aerosol modules give similar domain mean predictions of surface PM 2.5 concentrations but exhibit a strong spatial variation in magnitudes with large differences in eastern U.S. Large discrepancies are found in the predicted concentrations of sulfate and organic matter due to different treatments in secondary inorganic and secondary organic aerosol (SOA) formation. In particular, the nucleation calculation in MADE/SORGAM causes mass buildup of sulfate which results in much higher sulfate concentrations that those predicted by WRF/Chem with the other two aerosol modules. Different PM mass concentrations and size representations lead to differences in the predicted aerosol number concentrations. The above differences in PM concentrations lead to large differences in simulated condensation nuclei (CCN) and cloud properties in both months. The simulated ranges of domain mean are (1.9–14.3) × 10 9 m −3 and (1.4–5.4) × 10 9 m −3 for PM 2.5 number concentration, (1.6–3.9) × 10 8 cm −2 and (1.9–3.9) × 10 8 cm −2 for CCN, 102.9–208.2 cm −3 and 143.7–202.2 cm −3 for column cloud droplet number concentration (CDNC), and 4.5–6.4 and 3.6–6.7 for cloud optical depths (COT) in January and July, respectively. The sensitivity simulation for July 2001 using online biogenic emissions increases isoprene concentrations but decreases terpene concentrations, leading to a domain mean increase in O 3 (1.5 ppb) and a decrease in biogenic SOA (−0.07 µg m −3 ) and PM 2.5 (−0.2 µg m −3 ). Anthropogenic emissions contribute to O 3 , biogenic SOA (BSOA), and PM 2.5 concentrations by 38.0%, 44.2%, and 53.6% domain mean and by up to 78.5%, 89.7%, and 96.3%, respectively, indicating that a large fraction of BSOA is controllable through controlling atmospheric oxidant levels in CONUS. Anthropogenic emissions also contribute to a decrease in downward shortwave flux at ground surface (−5.8 W m −2 ), temperature at 2 m (−0.05°C), wind speed at 10 m (−0.02 m s −1 ), planetary boundary layer height (−6.6 m), and precipitation (−0.08 mm), as well as an increase in CCN (+5.7 × 10 −7 cm −2 ), in‐cloud CDNC (+40.4 cm −3 ), and COT (+0.6). This work indicates the need for an accurate representation of several aerosol processes such as SOA formation and aerosol‐cloud interactions in simulating aerosol direct and indirect effects in the online‐coupled models. DA - 2016/5/27/ PY - 2016/5/27/ DO - 10.1002/2016jd024882 VL - 121 IS - 10 SP - 6014-6048 SN - 2169-8996 ER - TY - JOUR TI - Origin of Miocene andesite and dacite in the Goldfield-Superstition volcanic province, central Arizona: Hybrids of mafic and silicic magma mixing AU - Fodor, R. V. AU - Johnson, Kelly G. T2 - GEOCHIMICA ET COSMOCHIMICA ACTA AB - The Miocene Goldfield–Superstition volcanic province (G-SVP), ∼8000 km2 in central Arizona, is composed largely of silicic pyroclastic rocks and lavas, and smaller volumes of alkalic basalt and intermediate-composition lavas. Volcanism began ∼20.5 Ma as sparse rhyolitic and mainly basaltic lavas followed by intermediate lavas, lasting until ∼19 Ma. At that time, ∼1 m.y. of silicic eruptions began, creating most of the G-SVP. Petrologic studies are available for basalts and some for silicic rocks, but petrologic/geochemical information is sparse for intermediate-composition lavas. These latter, andesites and dacites, are the focus of this study, in which we present the processes and sources responsible for their origins. Goldfield–Superstition andesites and dacites have SiO2 ∼56–70 wt.% and Na2O + K2O that qualifies some as trachy-andesite and -dacite. A prominent petrographic feature is plagioclase-phyric texture (∼11–30 vol% plagioclase), where oligoclase–andesine phenocrysts have cores surrounded by corroded, or reacted, zones, mantled by higher An% plagioclase. Where corroded zones are absent, margins are etched, curved, or embayed. Groundmass plagioclase is labradorite, also more calcic than the phenocrysts. Other minerals are quartz (subrounded; embayed), clinopyroxene, amphibole, biotite, and rare titanite and zircon. A salient compositional characteristic that provides insight to andesite–dacite origins with respect to other G-SVP rocks is revealed when using SiO2 as an index. Namely, abundances of many incompatible elements, mainly HFSE and REE, decrease over the low to high SiO2 range (i.e., abundances are lower in dacites than in co-eruptive andesites and underlying alkalic basalts). As examples: G-SVP basalts have ∼50–70 ppm La, and andesites–dacites have ∼59–22 ppm La; for Zr, basalts have ∼225–170 ppm, but most andesites–dacites have ∼180–50; for Y, basalts >20 ppm, andesites–dacites ∼18–9 ppm. To understand these trends of lower HFSE and REE with increasing SiO2, we modeled fractional crystallization of G-SVP alkalic basalt (∼50 wt.% SiO2; ∼9 wt.% MgO), dehydration melting (10–25%) of granodiorite and high-K amphibolite, and basalt–rhyolite magma mixing. Fractionation and melting each require specific modal percentages of titanite, zircon, and allanite (e.g., ⩽1%), the high ends of ranges for accessory-mineral/liquid partitioning coefficients, continual crystallization of accessory minerals from basalt to dacite (for fractionation), and specific source-melting percentages and low titanite, zircon, and allanite melting proportions (∼0.02; dehydration melting). These requirements are too stringent to be realistic. Moreover, accessory minerals are rare in these lavas, and neither fractionation nor melting accounts for the plagioclase textures observed. On the other hand, low-HFSE, -REE rhyolites (e.g., La 9–31 ppm; Zr 31–93; Nb 9–17; Y 4–10) containing Na-plagioclase are in the G-SVP and were temporally and spatially available to have mixed with G-SVP basalts. Mixing proportions of 20:80 to 90:10 for different rhyolite:basalt combinations yield hybrid compositions that overlap the G-SVP andesite–dacite compositional fields. Also, basalt invading rhyolite reservoirs containing mush zones can account for Na-plagioclase concentrations of ∼11–30 vol% formed after mush disruption and dispersal, plagioclase corroded-cores and higher-An% mantles and groundmass, and subrounded-embayed quartz. The straightforward explanation for G-SVP intermediate lavas, then, is repeated hybridization of basaltic and low-HFSE, -REE rhyolitic magmas during the early stages of G-SVP magmatism. DA - 2016/7/15/ PY - 2016/7/15/ DO - 10.1016/j.gca.2016.04.001 VL - 185 SP - 394-417 SN - 1872-9533 KW - Andesite origin KW - Dacite origin KW - Corroded plagioclase KW - Basalt fractional crystallization KW - Dehydration melting KW - Basalt-rhyolite magma mixing ER - TY - PCOMM TI - New directions: From biofuels to wood stoves: The modern and ancient air quality challenges in the megacity of Sao Paulo AU - Kumar, Prashant AU - Andrade, Maria de Fatima AU - Ynoue, Rita Yuri AU - Fornaro, Adalgiza AU - Freitas, Edmilson Dias AU - Martins, Jorge AU - Martins, Leila D. AU - Albuquerque, Taciana AU - Zhang, Yang AU - Morawska, Lidia AB - Generally, urban green infrastructure aids in the mitigation of air pollution. However, little is known about the role of densely packed vegetation canopies, such as Pueraria lobata (Willd.) Ohwi (kudzu) in air pollution mitigation. Here, we conducted field measurements of tropospheric ozone (O3) and nitrogen oxides (NOx) concentrations on a highway embankment slope with and without kudzu canopies in Japan. We measured O3 and NOx concentrations above and within the kudzu canopies by using a passive sampler several times during the growing season in 2019. The results demonstrated that both O3 and NOx concentrations reduced within the kudzu canopy throughout the growing season, suggesting that kudzu generally acts as “vegetation barrier” for both gas pollutants along the highway roadside. Depending on meteorological and vegetative surface conditions, the reduction rate within the canopy ranged from 11% to 64% and from −2% to 33% for O3 and NOx concentrations, respectively. Considering lower canopy height but higher leaf area density of kudzu than those for urban tree plantations or forest patches along the roadside, kudzu can be useful as green infrastructure depending on situations. We also found that the higher the leaf area index of kudzu canopies, the higher the reduction rates of O3 and NOx. Depending on the maintenance cost for roadside tree planting, the minimal management without targeting the eradication of kudzu over a certain area can be an option for realizing green infrastructure at least for maintaining local air quality during the growing season. DA - 2016/9// PY - 2016/9// DO - 10.1016/j.atmosenv.2016.05.059 SP - 364-369 ER - TY - JOUR TI - Metapopulation dynamics guide marine reserve design: importance of connectivity, demographics, and stock enhancement AU - Puckett, B. J. AU - Eggleston, D. B. T2 - ECOSPHERE AB - Abstract The concepts of metapopulation persistence and source‐sink dynamics are central and often untested tenets of marine reserve networks. Effective application of these concepts to marine reserves is limited by data on demographic rates within reserves and larval connectivity among reserves. Using a network of reserves established to restore eastern oyster ( Crassostrea virginica ) in Pamlico Sound, North Carolina, USA as our model system, we integrated empirically based demographic rates and regional hydrodynamic‐based connectivity estimates within a metapopulation model to (1) evaluate the potential for the reserve network to function as a self‐persistent oyster metapopulation, (2) determine the relative importance of demographics vs. connectivity on reserve source‐sink dynamics, (3) assess the efficacy of stock enhancement in promoting metapopulation persistence, and (4) evaluate whether application of a Few Large or Several Small reserves—a modification of the Single Large or Several Small concept—promoted greater metapopulation retention of larvae within the reserve network (i.e., local larval retention within reserves + larval connectivity among reserves). The reserve network failed to function as a self‐persistent metapopulation, despite exceptional demographic rates within reserves. When considering only larval supply from reserves, local retention and connectivity were insufficient to provide annual replacement (≥~0.25 recruits per adult). Accordingly, reserves contributed to the metapopulation primarily via production, not dispersal, of larvae and reserve source‐sink dynamics were influenced more by demographics within reserves, particularly adult growth and survival, than larval connectivity among reserves. Addressing recruitment limitation via stock enhancement was not effective at augmenting projected metapopulation declines. Several small reserves initially promoted greater metapopulation retention of larvae than a few large reserves, however, as the number or area of reserves increased, metapopulation retention was equivalent among designs, suggesting that Few Large and Several Small reserves may be the best network design. Marine reserves can be an effective restoration tool for improving demographic rates within reserve boundaries, but designation of multiple reserves does not guarantee a functional reserve network metapopulation. Both demographics and larval connectivity are important considerations to successful application of metapopulation concepts to the design of reserve networks. DA - 2016/6// PY - 2016/6// DO - 10.1002/ecs2.1322 VL - 7 IS - 6 SP - SN - 2150-8925 KW - connectivity KW - Crassostrea virginica KW - demographics KW - marine reserves KW - metapopulation dynamics KW - Pamlico Sound KW - persistence KW - restoration KW - Single Large or Several Small KW - stock enhancement ER - TY - JOUR TI - Measuring droplet fall speed with a high-speed camera: indoor accuracy and potential outdoor applications AU - Yu, Cheng-Ku AU - Hsieh, Pei-Rong AU - Yuter, Sandra E. AU - Cheng, Lin-Wen AU - Tsai, Chia-Lun AU - Lin, Che-Yu AU - Chen, Ying T2 - ATMOSPHERIC MEASUREMENT TECHNIQUES AB - Abstract. Acquisition of accurate raindrop fall speed measurements outdoors in natural rain by means of moderate-cost and easy-to-use devices represents a long-standing and challenging issue in the meteorological community. Feasibility experiments were conducted to evaluate the indoor accuracy of fall speed measurements made with a high-speed camera and to evaluate its capability for outdoor applications. An indoor experiment operating in calm conditions showed that the high-speed imaging technique can provide fall speed measurements with a mean error of 4.1–9.7 % compared to Gunn and Kinzer's empirical fall-speed–size relationship for typical sizes of rain and drizzle drops. Results obtained using the same apparatus outside in summer afternoon showers indicated larger positive and negative velocity deviations compared to the indoor measurements. These observed deviations suggest that ambient flow and turbulence play a role in modifying drop fall speeds which can be quantified with future outdoor high-speed camera measurements. Because the fall speed measurements, as presented in this article, are analyzed on the basis of tracking individual, specific raindrops, sampling uncertainties commonly found in the widely adopted optical disdrometers can be significantly mitigated. DA - 2016/// PY - 2016/// DO - 10.5194/amt-9-1755-2016 VL - 9 IS - 4 SP - 1755-1766 SN - 1867-8548 ER - TY - JOUR TI - Evaluating ammonia (NH3) predictions in the NOAA National Air Quality Forecast Capability (NAQFC) using in situ aircraft, ground-level, and satellite measurements from the DISCOVER-AQ Colorado campaign AU - Battye, William H. AU - Bray, Casey D. AU - Aneja, Viney P. AU - Tong, Daniel AU - Lee, Pius AU - Tang, Youhua T2 - ATMOSPHERIC ENVIRONMENT AB - The U.S. National Oceanic and Atmospheric Administration (NOAA) is responsible for forecasting elevated levels of air pollution within the National Air Quality Forecast Capability (NAQFC). The current research uses measurements gathered in the DISCOVER-AQ Colorado field campaign and the concurrent Front Range Air Pollution and Photochemistry Experiment (FRAPPE) to test performance of the NAQFC CMAQ modeling framework for predicting NH3. The DISCOVER-AQ and FRAPPE field campaigns were carried out in July and August 2014 in Northeast Colorado. Model predictions are compared with measurements of NH3 gas concentrations and the NH4+ component of fine particulate matter concentrations measured directly by the aircraft in flight. We also compare CMAQ predictions with NH3 measurements from ground-based monitors within the DISCOVER-AQ Colorado geographic domain, and from the Tropospheric Emission Spectrometer (TES) on the Aura satellite. In situ aircraft measurements carried out in July and August of 2014 suggest that the NAQFC CMAQ model underestimated the NH3 concentration in Northeastern Colorado by a factor of ∼2.7 (NMB = −63%). Ground-level monitors also produced a similar result. Average satellite-retrieved NH3 levels also exceeded model predictions by a factor of 1.5–4.2 (NMB = −33 to −76%). The underestimation of NH3 was not accompanied by an underestimation of particulate NH4+, which is further controlled by factors including acid availability, removal rate, and gas-particle partition. The average measured concentration of NH4+ was close to the average predication (NMB = +18%). Seasonal patterns measured at an AMoN site in the region suggest that the underestimation of NH3 is not due to the seasonal allocation of emissions, but to the overall annual emissions estimate. The underestimation of NH3 varied across the study domain, with the largest differences occurring in a region of intensive agriculture near Greeley, Colorado, and in the vicinity of Denver. The NAQFC modeling framework did not include a recently developed bidirectional flux algorithm for NH3, which has shown to considerably improve NH3 modeling in agricultural regions. The bidirectional flux algorithm, however, is not expected to obtain the magnitude of this increase sufficient to overcome the underestimation of NH3 found in this study. Our results suggest that further improvement of the emission inventories and modeling approaches are required to reduce the bias in NAQFC NH3 modeling predictions. DA - 2016/9// PY - 2016/9// DO - 10.1016/j.atmosenv.2016.06.021 VL - 140 SP - 342-351 SN - 1873-2844 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84973922839&partnerID=MN8TOARS KW - NH3 KW - Ammonia KW - Model evaluation KW - CMAQ KW - Aircraft measurement KW - Remote sensing ER - TY - JOUR TI - Divergence of ecosystem services in US National Forests and Grasslands under a changing climate AU - Duan, Kai AU - Sun, Ge AU - Sun, Shanlei AU - Caldwell, Peter V. AU - Cohen, Erika C. AU - McNulty, Steven G. AU - Aldridge, Heather D. AU - Zhang, Yang T2 - SCIENTIFIC REPORTS AB - The 170 National Forests and Grasslands (NFs) in the conterminous United States are public lands that provide important ecosystem services such as clean water and timber supply to the American people. This study investigates the potential impacts of climate change on two key ecosystem functions (i.e., water yield and ecosystem productivity) using the most recent climate projections derived from 20 Global Climate Models (GCMs) of the Coupled Model Intercomparison Project phase 5 (CMIP5). We find that future climate change may result in a significant reduction in water yield but an increase in ecosystem productivity in NFs. On average, gross ecosystem productivity is projected to increase by 76 ~ 229 g C m(-2) yr(-1) (8% ~ 24%) while water yield is projected to decrease by 18 ~ 31 mm yr(-1) (4% ~ 7%) by 2100 as a result of the combination of increased air temperature (+1.8 ~ +5.2 °C) and precipitation (+17 ~ +51 mm yr(-1)). The notable divergence in ecosystem services of water supply and carbon sequestration is expected to intensify under higher greenhouse gas emission and associated climate change in the future, posing greater challenges to managing NFs for both ecosystem services. DA - 2016/4/21/ PY - 2016/4/21/ DO - 10.1038/srep24441 VL - 6 SP - SN - 2045-2322 ER - TY - JOUR TI - Defining Planktonic Protist Functional Groups on Mechanisms for Energy and Nutrient Acquisition: Incorporation of Diverse Mixotrophic Strategies AU - Mitra, Aditee AU - Flynn, Kevin J. AU - Tillmann, Urban AU - Raven, John A. AU - Caron, David AU - Stoecker, Diane K. AU - Not, Fabrice AU - Hansen, Per J. AU - Hallegraeff, Gustaaf AU - Sanders, Robert AU - Wilken, Susanne AU - McManus, George AU - Johnson, Mathew AU - Pitta, Paraskevi AU - Våge, Selina AU - Berge, Terje AU - Calbet, Albert AU - Thingstad, Frede AU - Jeong, Hae Jin AU - Burkholder, JoAnn AU - Glibert, Patricia M. AU - Granéli, Edna AU - Lundgren, Veronica T2 - Protist AB - Arranging organisms into functional groups aids ecological research by grouping organisms (irrespective of phylogenetic origin) that interact with environmental factors in similar ways. Planktonic protists traditionally have been split between photoautotrophic "phytoplankton" and phagotrophic "microzooplankton". However, there is a growing recognition of the importance of mixotrophy in euphotic aquatic systems, where many protists often combine photoautotrophic and phagotrophic modes of nutrition. Such organisms do not align with the traditional dichotomy of phytoplankton and microzooplankton. To reflect this understanding, we propose a new functional grouping of planktonic protists in an eco-physiological context: (i) phagoheterotrophs lacking phototrophic capacity, (ii) photoautotrophs lacking phagotrophic capacity, (iii) constitutive mixotrophs (CMs) as phagotrophs with an inherent capacity for phototrophy, and (iv) non-constitutive mixotrophs (NCMs) that acquire their phototrophic capacity by ingesting specific (SNCM) or general non-specific (GNCM) prey. For the first time, we incorporate these functional groups within a foodweb structure and show, using model outputs, that there is scope for significant changes in trophic dynamics depending on the protist functional type description. Accordingly, to better reflect the role of mixotrophy, we recommend that as important tools for explanatory and predictive research, aquatic food-web and biogeochemical models need to redefine the protist groups within their frameworks. DA - 2016/4// PY - 2016/4// DO - 10.1016/J.PROTIS.2016.01.003 VL - 167 IS - 2 SP - 106-120 J2 - Protist LA - en OP - SN - 1434-4610 UR - http://dx.doi.org/10.1016/J.PROTIS.2016.01.003 DB - Crossref KW - Plankton functional types (PFTs) KW - phagotroph KW - phototroph KW - mixotroph KW - phytoplankton KW - microzooplankton ER - TY - JOUR TI - Comprehensive evaluation of multi-year real-time air quality forecasting using an online-coupled meteorology-chemistry model over southeastern United States AU - Zhang, Yang AU - Hong, Chaopeng AU - Yahya, Khairunnisa AU - Li, Qi AU - Zhang, Qiang AU - He, Kebin T2 - ATMOSPHERIC ENVIRONMENT AB - An online-coupled meteorology-chemistry model, WRF/Chem-MADRID, has been deployed for real time air quality forecast (RT-AQF) in southeastern U.S. since 2009. A comprehensive evaluation of multi-year RT-AQF shows overall good performance for temperature and relative humidity at 2-m (T2, RH2), downward surface shortwave radiation (SWDOWN) and longwave radiation (LWDOWN), and cloud fraction (CF), ozone (O3) and fine particles (PM2.5) at surface, tropospheric ozone residuals (TOR) in O3 seasons (May-September), and column NO2 in winters (December-February). Moderate-to-large biases exist in wind speed at 10-m (WS10), precipitation (Precip), cloud optical depth (COT), ammonium (NH4+), sulfate (SO42−), and nitrate (NO3−) from the IMPROVE and SEARCH networks, organic carbon (OC) at IMPROVE, and elemental carbon (EC) and OC at SEARCH, aerosol optical depth (AOD) and column carbon monoxide (CO), sulfur dioxide (SO2), and formaldehyde (HCHO) in both O3 and winter seasons, column nitrogen dioxide (NO2) in O3 seasons, and TOR in winters. These biases indicate uncertainties in the boundary layer and cloud process treatments (e.g., surface roughness, microphysics cumulus parameterization), emissions (e.g., O3 and PM precursors, biogenic, mobile, and wildfire emissions), upper boundary conditions for all major gases and PM2.5 species, and chemistry and aerosol treatments (e.g., winter photochemistry, aerosol thermodynamics). The model shows overall good skills in reproducing the observed multi-year trends and inter-seasonal variability in meteorological and radiative variables such as T2, WS10, Precip, SWDOWN, and LWDOWN, and relatively well in reproducing the observed trends in surface O3 and PM2.5, but relatively poor in reproducing the observed column abundances of CO, NO2, SO2, HCHO, TOR, and AOD. The sensitivity simulations using satellite-constrained boundary conditions for O3 and CO show substantial improvement for both spatial distribution and domain-mean performance statistics. The model’s forecasting skills for air quality can be further enhanced through improving model inputs (e.g., anthropogenic emissions for urban areas and upper boundary conditions of chemical species), meteorological forecasts (e.g., WS10, Precip) and meteorologically-dependent emissions (e.g., biogenic and wildfire emissions), and model physics and chemical treatments (e.g., gas-phase chemistry in winter conditions, cloud processes and their interactions with radiation and aerosol). DA - 2016/8// PY - 2016/8// DO - 10.1016/j.atmosenv.2016.05.006 VL - 138 SP - 162-182 SN - 1873-2844 KW - WRF/Chem-MADRID KW - Southeastern US KW - Discrete evaluation KW - Categorical evaluation KW - Satellite data KW - Multi-year trend analysis ER - TY - JOUR TI - Association of extreme precipitation over the Yangtze River Basin with global air-sea heat fluxes and moisture transport AU - Gao, Tao AU - Xie, Lian AU - Liu, Bin T2 - INTERNATIONAL JOURNAL OF CLIMATOLOGY AB - ABSTRACT Although the effect of sea surface temperature anomalies in the Pacific and Indian Oceans on precipitation over the Yangtze River Basin ( YRB ) is well known, the impact of air–sea sensible and latent heat fluxes ( SHF and LHF ) has not been well studied. Based on the statistical and diagnostic analyses of historical precipitation data over the YRB , SHF and LHF over the global ocean, as well as global atmospheric reanalysis data, the impacts of SHF and LHF in the selected ocean regions on YRB extreme precipitation were investigated. The spatial distributions of the correlation coefficients between the YRB extreme precipitation indices ( YRB‐EPI ) and SHF and LHF over the global ocean were analysed to identify critical air–sea interaction regions affecting YRB extreme precipitation. Results show that a significant positive correlation exists between YRB‐EPI and air–sea heat fluxes over the Northwest Indian Ocean, Southeast Indian Ocean, Southwest Indian Ocean and South China Sea regions. Negative correlations were found over Central Equatorial Pacific, while positive lagged correlations exist over East Pacific. Composite analyses of global wind, geo‐potential height and water vapour transport were also conducted for ten heaviest and ten lightest YRB precipitation years, respectively. In heavy YRB precipitation years, the atmospheric circulation pattern is generally characterized by a strengthened Western Pacific Subtropical High ( WPSH ) extending northwestward, a strengthened lower tropospheric convergence zone over the YRB , three distinct moisture transport paths from adjacent oceans to the YRB and low‐level mid‐latitude northerly wind anomalies. Whereas, in light YRB precipitation years, it is dominated by the southwesterly summer monsoon over the YRB , with a convergence zone displaced to the north of the YRB , a weak WPSH , and only two main paths of moisture transport. These distinctions between the heavy and light YRB precipitation years provide a physical basis for establishing a statistical prediction model for YRB extreme precipitation. DA - 2016/6/30/ PY - 2016/6/30/ DO - 10.1002/joc.4534 VL - 36 IS - 8 SP - 3020-3038 SN - 1097-0088 KW - extreme precipitation events KW - latent heat flux KW - sensible heat flux KW - sea surface temperature KW - Yangtze River Basin ER - TY - JOUR TI - Assessing the impact of climate variability on runoff using a new linear runoff generation model AU - Deng, P. AU - Zhu, J. T. AU - Sun, S. L. AU - Guo, Y. T2 - Hydrological Sciences Journal-Journal Des Sciences Hydrologiques DA - 2016/// PY - 2016/// VL - 61 IS - 6 SP - 1040-1053 ER - TY - JOUR TI - Ankylosaurian dinosaur palaeoenvironmental associations were influenced by extirpation, sea-level fluctuation, and geodispersal AU - Arbour, Victoria M. AU - Zanno, Lindsay E. AU - Gates, Terry T2 - PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY AB - More species of nodosaurid ankylosaurians than ankylosaurid ankylosaurians have been found in marine sediments, and some previous quantitative studies of global dinosaur occurrences provide support for an association between nodosaurids and marine depositional environments. We compiled a dataset of global ankylosaurian occurrences and found that the geographic distribution of marine ankylosaurian occurrences is regionally biased with 54% of records stemming from western North America in the Cretaceous—a time of regional highstands in sea level and epicontinental flooding, coupled with differential extirpation of ankylosaurian subclades inhabiting the Western Interior Basin (WIB). Within the Western Interior Basin, we found little statistical support for an association between ankylosaurian subclades and palaeoenvironment in a chronological context. Only the Albian–Cenomanian transgressive–regressive cycle had statistical support for an overabundance of nodosaurids in marine environments compared to ankylosaurids. The apparent overabundance of nodosaurids relative to ankylosaurids in marine sediments in the Western Interior Basin overall cannot be decoupled from the extirpation of North American ankylosaurids during the Cenomanian and the subsequent absence of ankylosaurids in North America during the Turonian to early Campanian prior to the immigration of Asian ankylosaurine ankylosaurids. The North American ankylosaurian record highlights the difficulty in interpreting habitat preferences in the context of a shifting seaway, regional extinctions, and intercontinental dispersals. DA - 2016/5/1/ PY - 2016/5/1/ DO - 10.1016/j.palaeo.2016.02.033 VL - 449 SP - 289-299 SN - 1872-616X KW - Cretaceous KW - Western Interior Basin KW - Ankylosauria KW - Ankylosauridae KW - Nodosauridae KW - Dinosauria ER - TY - JOUR TI - Statistical downscaling of IPCC sea surface wind and wind energy predictions for US east coastal ocean, Gulf of Mexico and Caribbean Sea AU - Zhigang, Yao AU - Zuo, Xue AU - Ruoying, He AU - Xianwen, Bao AU - Jun, Song T2 - JOURNAL OF OCEAN UNIVERSITY OF CHINA DA - 2016/8// PY - 2016/8// DO - 10.1007/s11802-016-2869-0 VL - 15 IS - 4 SP - 577-582 SN - 1993-5021 KW - climate changes KW - statistical downscaling KW - surface winds ER - TY - JOUR TI - Seasonal and regional variations in extreme precipitation event frequency using CMIP5 AU - Janssen, E. AU - Sriver, R. L. AU - Wuebbles, D. J. AU - Kunkel, K. E. T2 - GEOPHYSICAL RESEARCH LETTERS AB - Abstract Understanding how the frequency and intensity of extreme precipitation events are changing is important for regional risk assessments and adaptation planning. Here we use observational data and an ensemble of climate change model experiments (from the Coupled Model Intercomparison Project Phase 5 (CMIP5)) to examine past and potential future seasonal changes in extreme precipitation event frequency over the United States. Using the extreme precipitation index as a metric for extreme precipitation change, we find key differences between models and observations. In particular, the CMIP5 models tend to overestimate the number of spring events and underestimate the number of summer events. This seasonal shift in the models is amplified in projections. These results provide a basis for evaluating climate model skill in simulating observed seasonality and changes in regional extreme precipitation. Additionally, we highlight key sources of variability and uncertainty that can potentially inform regional impact analyses and adaptation planning. DA - 2016/5/28/ PY - 2016/5/28/ DO - 10.1002/2016gl069151 VL - 43 IS - 10 SP - 5385-5393 SN - 1944-8007 ER - TY - JOUR TI - Quantifying the fate of agricultural nitrogen in an unconfined aquifer: Stream-based observations at three measurement scales AU - Gilmore, Troy E. AU - Genereux, David P. AU - Solomon, D. Kip AU - Solder, John E. AU - Kimball, Briant A. AU - Mitasova, Helena AU - Birgand, Francois T2 - WATER RESOURCES RESEARCH AB - Abstract We compared three stream‐based sampling methods to study the fate of nitrate in groundwater in a coastal plain watershed: point measurements beneath the streambed, seepage blankets (novel seepage‐meter design), and reach mass‐balance. The methods gave similar mean groundwater seepage rates into the stream (0.3–0.6 m/d) during two 3–4 day field campaigns despite an order of magnitude difference in stream discharge between the campaigns. At low flow, estimates of flow‐weighted mean nitrate concentrations in groundwater discharge ([ ] FWM ) and nitrate flux from groundwater to the stream decreased with increasing degree of channel influence and measurement scale, i.e., [ ] FWM was 654, 561, and 451 µ M for point, blanket, and reach mass‐balance sampling, respectively. At high flow the trend was reversed, likely because reach mass‐balance captured inputs from shallow transient high‐nitrate flow paths while point and blanket measurements did not. Point sampling may be better suited to estimating aquifer discharge of nitrate, while reach mass‐balance reflects full nitrate inputs into the channel (which at high flow may be more than aquifer discharge due to transient flow paths, and at low flow may be less than aquifer discharge due to channel‐based nitrate removal). Modeling dissolved N 2 from streambed samples suggested (1) about half of groundwater nitrate was denitrified prior to discharge from the aquifer, and (2) both extent of denitrification and initial nitrate concentration in groundwater (700–1300 µ M ) were related to land use, suggesting these forms of streambed sampling for groundwater can reveal watershed spatial relations relevant to nitrate contamination and fate in the aquifer. DA - 2016/3// PY - 2016/3// DO - 10.1002/2015wr017599 VL - 52 IS - 3 SP - 1961-1983 SN - 1944-7973 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84977952435&partnerID=MN8TOARS KW - unconfined aquifer KW - nonpoint source nitrogen KW - groundwater contamination KW - coastal plain KW - denitrification KW - hyphoreic zone ER - TY - JOUR TI - Prediction of cloud condensation nuclei activity for organic compounds using functional group contribution methods AU - Petters, M. D. AU - Kreidenweis, S. M. AU - Ziemann, P. J. T2 - Geoscientific Model Development DA - 2016/// PY - 2016/// VL - 9 IS - 1 SP - 111-124 ER - TY - JOUR TI - Keratin durability has implications for the fossil record: Results from a 10 year feather degradation experiment AU - Moyer, A. E. AU - Zheng, W. X. AU - Schweitzer, M. H. T2 - PLoS One DA - 2016/// PY - 2016/// VL - 11 IS - 7 ER - TY - JOUR TI - Innovations in science and scenarios for assessment AU - Kunkel, Kenneth E. AU - Moss, Richard AU - Parris, Adam T2 - CLIMATIC CHANGE AB - Scenarios for the Third National Climate Assessment (NCA3) were produced for physical climate and sea level rise with substantial input from disciplinary and regional experts. These scenarios underwent extensive review and were published as NOAA Technical Reports. For land use/cover and socioeconomic conditions, scenarios already developed by other agencies were specified for use in the NCA3. Efforts to enhance participatory scenario planning as an assessment activity were pursued, but with limited success. Issues and challenges included the timing of availability of scenarios, the need for guidance in use of scenarios, the need for approaches to nest information within multiple scales and sectors, engagement and collaboration of end users in scenario development, and development of integrated scenarios. Future assessments would benefit from an earlier start to scenarios development, the provision of training in addition to guidance documents, new and flexible approaches for nesting information, ongoing engagement and advice from both scientific and end user communities, and the development of consistent and integrated scenarios. DA - 2016/3// PY - 2016/3// DO - 10.1007/s10584-015-1494-z VL - 135 IS - 1 SP - 55-68 SN - 1573-1480 ER - TY - JOUR TI - Innovations in information management and access for assessments AU - Waple, A. M. AU - Champion, S. M. AU - Kunkel, K. E. AU - Tilmes, C. T2 - Climatic Change AB - The third National Climate Assessment (NCA3) included goals for becoming a more timely, inclusive, rigorous, and sustained process, and for serving a wider variety of decision makers. In order to accomplish these goals, it was necessary to deliberately design an information management strategy that could serve multiple stakeholders and manage different types of information - from highly mature government-supported climate science data, to isolated practitioner-generated case study information - and to do so in ways that are consistent and appropriate for a highly influential assessment. Meeting the information management challenge for NCA3 meant balancing relevance and authority, complexity and accessibility, inclusivity and rigor. Increasing traceability of data behind figures and graphics, designing a public-facing website, managing hundreds of technical inputs to the NCA, and producing guidance for over 300 participants on meeting the Information Quality Act were all aspects of a deliberate, multi-faceted, and strategic information management approach that nonetheless attempted to be practical and usable for a variety of participants and stakeholders. DA - 2016/// PY - 2016/// DO - 10.1007/s10584-015-1588-7 VL - 135 IS - 1 SP - 69-83 ER - TY - JOUR TI - Groundwater transit time distribution and mean from streambed sampling in an agricultural coastal plain watershed, North Carolina, USA AU - Gilmore, Troy E. AU - Genereux, David P. AU - Solomon, D. Kip AU - Solder, John E. T2 - WATER RESOURCES RESEARCH AB - Abstract We measured groundwater apparent age ( τ ) and seepage rate ( v ) in a sandy streambed using point‐scale sampling and seepage blankets (a novel seepage meter). We found very similar MTT estimates from streambed point sampling in a 58 m reach (29 years) and a 2.5 km reach (31 years). The TTD for groundwater discharging to the stream was best fit by a gamma distribution model and was very similar for streambed point sampling in both reaches. Between adjacent point‐scale and seepage blanket samples, water from the seepage blankets was generally younger, largely because blanket samples contained a fraction of “young” stream water. Correcting blanket data for the stream water fraction brought τ estimates for most blanket samples closer to those for adjacent point samples. The MTT estimates from corrected blanket data were in good agreement with those from sampling streambed points adjacent to the blankets. Collectively, agreement among age‐dating tracers, general accord between tracer data and piston‐flow model curves, and large groundwater age gradients in the streambed, suggested that the piston flow apparent ages were reasonable estimates of the groundwater transit times for most samples. Overall, our results from two field campaigns suggest that groundwater collected in the streambed can provide reasonable estimates of apparent age of groundwater discharge, and that MTT can be determined from different age‐dating tracers and by sampling with different groundwater collection devices. Coupled streambed point measurements of groundwater age and groundwater seepage rate represent a novel, reproducible, and effective approach to estimating aquifer TTD and MTT . DA - 2016/3// PY - 2016/3// DO - 10.1002/2015wr017600 VL - 52 IS - 3 SP - 2025-2044 SN - 1944-7973 KW - groundwater transit time distribution KW - gamma distribution KW - groundwater mean transit time KW - seepage meter KW - unconfined aquifer KW - groundwater age ER - TY - JOUR TI - Extending a surface-layer C-n(2) model for strongly stratified conditions utilizing a numerically generated turbulence dataset AU - He, Ping AU - Basu, Sukanta T2 - OPTICS EXPRESS AB - In Wyngaard et al., 1971, a simple model was proposed to estimate Cn2 in the atmospheric surface layer, which only requires routine meteorological information (wind speed and temperature) as input from two heights. This Cn2 model is known to have satisfactory performance in unstable conditions; however, in stable conditions, the model only covers a relatively short range of atmospheric stabilities which significantly limits its applicability during nighttime. To mitigate this limitation, in this study we construct a new Cn2 model utilizing an extensive turbulence dataset generated by a high-fidelity numerical modeling approach (known as direct numerical simulation). The most distinguishing feature of this new Cn2 model is that it covers a wide range of atmospheric stabilities including the strongly stratified (very stable) conditions. To validate this model, approximately four weeks of Cn2 data collected at the Mauna Loa Observatory, Hawaii are used for comparison, and reasonably good agreement is found between the observed and estimated values. DA - 2016/5/2/ PY - 2016/5/2/ DO - 10.1364/oe.24.009574 VL - 24 IS - 9 SP - 9574-9582 SN - 1094-4087 ER - TY - JOUR TI - Development of similarity relationships for energy dissipation rate and temperature structure parameter in stably stratified flows: a direct numerical simulation approach AU - He, Ping AU - Basu, Sukanta T2 - ENVIRONMENTAL FLUID MECHANICS DA - 2016/4// PY - 2016/4// DO - 10.1007/s10652-015-9427-y VL - 16 IS - 2 SP - 373-399 SN - 1573-1510 KW - Direct numerical simulation KW - Energy dissipation rate KW - Large-eddy simulation KW - Similarity theory KW - Stable boundary layer KW - Temperature structure parameter ER - TY - JOUR TI - Decadal evaluation of regional climate, air quality, and their interactions over the continental US and their interactions using WRF/Chem version 3.6.1 AU - Yahya, K. AU - Wang, K. AU - Campbell, P. AU - Glotfelty, T. AU - He, J. AU - Zhang, Y. T2 - Geoscientific Model Development DA - 2016/// PY - 2016/// VL - 9 IS - 2 SP - 671-695 ER - TY - JOUR TI - Acceleration of oxygen decline in the tropical Pacific over the past decades by aerosol pollutants AU - Ito, T. AU - Nenes, A. AU - Johnson, M. S. AU - Meskhidze, N. AU - Deutsch, C. T2 - NATURE GEOSCIENCE DA - 2016/6// PY - 2016/6// DO - 10.1038/ngeo2717 VL - 9 IS - 6 SP - 443-+ SN - 1752-0908 ER - TY - JOUR TI - Variation of energy and carbon fluxes from a restored temperate freshwater wetland and implications for carbon market verification protocols AU - Anderson, Frank E. AU - Bergamaschi, Brian AU - Sturtevant, Cove AU - Knox, Sara AU - Hastings, Lauren AU - Windham-Myers, Lisamarie AU - Detto, Matteo AU - Hestir, Erin L. AU - Drexler, Judith AU - Miller, Robin L. AU - Matthes, Jaclyn Hatala AU - Verfaillie, Joseph AU - Baldocchi, Dennis AU - Snyder, Richard L. AU - Fujii, Roger T2 - JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES AB - Abstract Temperate freshwater wetlands are among the most productive terrestrial ecosystems, stimulating interest in using restored wetlands as biological carbon sequestration projects for greenhouse gas reduction programs. In this study, we used the eddy covariance technique to measure surface energy carbon fluxes from a constructed, impounded freshwater wetland during two annual periods that were 8 years apart: 2002–2003 and 2010–2011. During 2010–2011, we measured methane (CH 4 ) fluxes to quantify the annual atmospheric carbon mass balance and its concomitant influence on global warming potential (GWP). Peak growing season fluxes of latent heat and carbon dioxide (CO 2 ) were greater in 2002–2003 compared to 2010–2011. In 2002, the daily net ecosystem exchange reached as low as −10.6 g C m −2 d −1 , which was greater than 3 times the magnitude observed in 2010 (−2.9 g C m −2 d −1 ). CH 4 fluxes during 2010–2011 were positive throughout the year and followed a strong seasonal pattern, ranging from 38.1 mg C m −2 d −1 in the winter to 375.9 mg C m −2 d −1 during the summer. The results of this study suggest that the wetland had reduced gross ecosystem productivity in 2010–2011, likely due to the increase in dead plant biomass (standing litter) that inhibited the generation of new vegetation growth. In 2010–2011, there was a net positive GWP (675.3 g C m −2 yr −1 ), and when these values are evaluated as a sustained flux, the wetland will not reach radiative balance even after 500 years. DA - 2016/3// PY - 2016/3// DO - 10.1002/2015jg003083 VL - 121 IS - 3 SP - 777-795 SN - 2169-8961 KW - wetlands KW - eddy covariance KW - carbon dioxide KW - methane KW - carbon market KW - global warming potential ER - TY - JOUR TI - Temporal soundscape patterns and processes in an estuarine reserve AU - Ricci, Shannon W. AU - Eggleston, David B. AU - Bohnenstiehl, DelWayne R. AU - Lillis, Ashlee T2 - MARINE ECOLOGY PROGRESS SERIES AB - MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 550:25-38 (2016) - DOI: https://doi.org/10.3354/meps11724 Temporal soundscape patterns and processes in an estuarine reserve Shannon W. Ricci1,*, David B. Eggleston1,2, DelWayne R. Bohnenstiehl1, Ashlee Lillis1,3 1Department of Marine, Earth & Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695-8208, USA 2Center for Marine Sciences and Technology, North Carolina State University, Morehead City, North Carolina 28557, USA 3Present address: Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA *Corresponding author: swbrown@ncsu.edu ABSTRACT: Underwater acoustic recordings can be used to measure the distribution and activity of sound-producing species and investigate variability in the physical and biological characteristics of marine ecosystems. This study characterized the summer soundscape of a coastal estuarine reserve, Middle Marsh, near Beaufort Inlet, North Carolina, USA. Passive recorders were deployed at 8 sites, within a mixture of seagrass, saltmarsh, oyster reef and soft-bottom habitats, and sampled for 2 min every 20 min between June and August 2014. Sound pressure levels (SPLs) in a high-frequency band (7-43 kHz) exhibited a periodicity of once per day, being 11 dB higher during the nighttime. This pattern is correlated with snapping shrimp sounds, with an average excess of ~12% more snaps detected at night. The same analysis for SPLs in a low-frequency band (150-1500 Hz) revealed a periodicity of twice per day, with diurnal sound levels varying by up to 29 dB. Temporal variability in the low-frequency soundscape is correlated with fish chorusing, as well as tidal water level, which may influence both the presence and absence of fish and the propagation of sound in the water column. The greatest SPLs are observed in association with periods of high biological activity during nighttime high tides. Sampling marine animals and their activities over ecologically relevant time scales is challenging using conventional techniques (trawls and throw traps) within complex shallow water habitats, particularly at night. Soundscape monitoring provides an additional method to assess spatiotemporal variation in essential fish habitat use within a complex mosaic of habitat types. KEY WORDS: Passive acoustics · Habitat-related sound · Soundscapes · Estuarine habitats Full text in pdf format Supplementary material PreviousNextCite this article as: Ricci SW, Eggleston DB, Bohnenstiehl DR, Lillis A (2016) Temporal soundscape patterns and processes in an estuarine reserve. Mar Ecol Prog Ser 550:25-38. https://doi.org/10.3354/meps11724 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 550. Online publication date: May 25, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research. DA - 2016/5/25/ PY - 2016/5/25/ DO - 10.3354/meps11724 VL - 550 SP - 25-38 SN - 1616-1599 KW - Passive acoustics KW - Habitat-related sound KW - Soundscapes KW - Estuarine habitats ER - TY - JOUR TI - Structural impact assessment of low level jets over wind turbines AU - Gutierrez, W. AU - Araya, G. AU - Kiliyanpilakkil, P. AU - Ruiz-Columbie, A. AU - Tutkun, M. AU - Castillo, L. T2 - Journal of Renewable and Sustainable Energy DA - 2016/// PY - 2016/// VL - 8 IS - 2 ER - TY - JOUR TI - Specializations of the mandibular anatomy and dentition of Segnosaurus galbinensis (Theropoda: Therizinosauria) AU - Zanno, L. E. AU - Tsogtbaatar, K. AU - Chinzorig, T. AU - Gates, T. A. T2 - PeerJ DA - 2016/// PY - 2016/// VL - 4 ER - TY - JOUR TI - Projecting water yield and ecosystem productivity across the United States by linking an ecohydrological model to WRF dynamically downscaled climate data AU - Sun, S. L. AU - Sun, G. AU - Cohen, E. AU - McNulty, S. G. AU - Caldwell, P. V. AU - Duan, K. AU - Zhang, Y. T2 - Hydrology and Earth System Sciences DA - 2016/// PY - 2016/// VL - 20 IS - 2 SP - 935-952 ER - TY - JOUR TI - Novel species interactions in a highly modified estuary: Association of largemouth bass with Brazilian waterweed Egeria densa AU - Conrad, J. L. AU - Bibian, A. J. AU - Weinersmith, K. L. AU - De Carion, D. AU - Young, M. J. AU - Crain, P. AU - Hestir, E. L. AU - Santos, M. J. AU - Sih, A. T2 - Transactions of the American Fisheries Society AB - Abstract Frequent invasions in coastal ecosystems result in novel species interactions that have unknown ecological consequences. Largemouth Bass Micropterus salmoides and Brazilian waterweed Egeria densa are introduced species in the Sacramento–San Joaquin River Delta (the Delta) of California, a highly modified estuary. In this system, Brazilian waterweed and Largemouth Bass have seen marked increases in distribution and abundance in recent decades, but their association has not been specifically studied until now. We conducted a 2‐year, bimonthly electrofishing survey with simultaneous sampling of water quality and submerged aquatic vegetation (SAV) biomass at 33 locations throughout the Delta. We used generalized linear mixed models to assess the relative influences of water temperature, conductivity, Secchi depth, and SAV biomass density on the abundance of both juvenile‐sized and larger Largemouth Bass. Water temperature had a positive relationship with the abundance of both size‐classes, but only juvenile‐sized fish had a positive association with SAV biomass density, with highest abundances at intermediate SAV densities. In contrast, larger fish were generally ubiquitous across all sampling conditions, even when SAV was absent or present at low densities. Our results on the Largemouth Bass–SAV relationship are consistent with those of previous studies from lake systems within the Largemouth Bass's native range, where they interact with a different SAV species assemblage. These results are supportive of the hypothesis that the proliferation of Brazilian waterweed has expanded Largemouth Bass rearing habitat in the Delta. Finally, this study has implications for tidal wetland restoration plans for the Delta, suggesting that the larger‐sized Largemouth Bass may still inhabit restored areas even if invasive SAV establishment is limited. Received March 30, 2015; accepted October 27, 2015 DA - 2016/// PY - 2016/// DO - 10.1080/00028487.2015.1114521 VL - 145 IS - 2 SP - 249-263 ER - TY - JOUR TI - Tissue Extraction Methods for Metabolic Profiling of a Freshwater Bivalve, Elliptio complanata (Lightfoot, 1786) AU - Hurley-Sanders, Jennifer L. AU - Stoskopf, Michael K. AU - Nelson, Stacy A. C. AU - Showers, William AU - Law, J. Mac AU - Gracz, Hanna S. AU - Levine, Jay F. T2 - American Malacological Bulletin AB - Much is still unknown about why freshwater mussels (Unionidae) are particularly sensitive to environmental change. A better understanding of freshwater mussel metabolism is needed, and the field of environmental metabolomics holds the promise to inform these questions. A number of protocols exist for the extraction of metabolites for identification from animal tissues. As a first step in the application of environmental metabolomics to the study of freshwater mussels, we compared extraction protocols using an inorganic oxidizing acid (perchloric acid), an organic nitrile (acetonitrile), and a salt/water solution (Ringer's solution) to establish an uncomplicated, robust, repeatable and inexpensive tissue extraction protocol for freshwater mussel tissue. Perchloric acid resulted in notable extraction of energy-related nucleotides (AMP/ADP/ATP), yet had the lowest peak count of the three extraction methods and showed poor repeatability. Acetonitrile and Ringer's solution yielded metabolite extraction results similar to each other with Ringer's solution having the greatest number of peaks particularly in the 3.0–4.5 ppm sugar/amino acid range. Ringer's solution is simple to use, safe and consistent and bears consideration when selecting an extraction protocol for 1H nuclear magnetic resonance experiments. DA - 2016/1// PY - 2016/1// DO - 10.4003/006.033.0209 VL - 33 IS - 2 SP - 185–194 SN - 0740-2783 2162-2698 UR - http://dx.doi.org/10.4003/006.033.0209 KW - freshwater bivalve KW - metabolomics KW - NMR KW - nuclear magnetic resonance KW - Ringer's solution ER - TY - JOUR TI - The Curious Acoustic Behavior of Estuarine Snapping Shrimp: Temporal Patterns of Snapping Shrimp Sound in Sub-Tidal Oyster Reef Habitat AU - Bohnenstiehl, DelWayne R. AU - Lillis, Ashlee AU - Eggleston, David B. T2 - PLOS ONE AB - Ocean soundscapes convey important sensory information to marine life. Like many mid-to-low latitude coastal areas worldwide, the high-frequency (>1.5 kHz) soundscape of oyster reef habitat within the West Bay Marine Reserve (36°N, 76°W) is dominated by the impulsive, short-duration signals generated by snapping shrimp. Between June 2011 and July 2012, a single hydrophone deployed within West Bay was programmed to record 60 or 30 seconds of acoustic data every 15 or 30 minutes. Envelope correlation and amplitude information were then used to count shrimp snaps within these recordings. The observed snap rates vary from 1500–2000 snaps per minute during summer to <100 snaps per minute during winter. Sound pressure levels are positively correlated with snap rate (r = 0.71–0.92) and vary seasonally by ~15 decibels in the 1.5–20 kHz range. Snap rates are positively correlated with water temperatures (r = 0.81–0.93), as well as potentially influenced by climate-driven changes in water quality. Light availability modulates snap rate on diurnal time scales, with most days exhibiting a significant preference for either nighttime or daytime snapping, and many showing additional crepuscular increases. During mid-summer, the number of snaps occurring at night is 5–10% more than predicted by a random model; however, this pattern is reversed between August and April, with an excess of up to 25% more snaps recorded during the day in the mid-winter. Diurnal variability in sound pressure levels is largest in the mid-winter, when the overall rate of snapping is at its lowest, and the percentage difference between daytime and nighttime activity is at its highest. This work highlights our lack of knowledge regarding the ecology and acoustic behavior of one of the most dominant soniforous invertebrate species in coastal systems. It also underscores the necessity of long-duration, high-temporal-resolution sampling in efforts to understand the bioacoustics of animal behaviors and associated changes within the marine soundscape. DA - 2016/1/13/ PY - 2016/1/13/ DO - 10.1371/journal.pone.0143691 VL - 11 IS - 1 SP - SN - 1932-6203 ER - TY - JOUR TI - Testing the hypothesis of biofilm as a source for soft tissue and cell-like structures preserved in dinosaur bone AU - Schweitzer, M. H. AU - Moyer, A. E. AU - Zheng, W. X. T2 - PLoS One DA - 2016/// PY - 2016/// VL - 11 IS - 2 ER - TY - JOUR TI - Resonance-Enhanced Raman Scattering of Ring-Involved Vibrational Modes in the B-1(2u) Absorption Band of Benzene, Including the Kekule Vibrational Modes nu(9) and nu(10) AU - Willitsford, Adam H. AU - Chadwick, C. Todd AU - Kurtz, Stewart AU - Philbrick, C. Russell AU - Hallen, Hans T2 - JOURNAL OF PHYSICAL CHEMISTRY A AB - Resonance Raman spectroscopy provides much stronger Raman signal levels than its off-resonant counterpart and adds selectivity by excitation tuning. Raman preresonance of benzene has been well studied. On-resonance studies, especially at phonon-allowed absorptions, have received less attention. In this case, we observe resonance of many of the vibration modes associated motion of the carbons in the ring while tuning over the (1)B2u absorption, including the related ν9 (CC stretch Herzberg notation, ν14 Wilson notation) and ν10 (CH-parallel bend Herzberg notation, ν15 Wilson notation) vibrational modes along with the ν2 (CC-stretch or ring-breathing Herzberg notation, ν1 Wilson notation) mode and multiples of the ν18 (CCC-parallel bend Herzberg notation, ν6 Wilson notation) vibrational mode. The ring-breathing mode is found to mix with the b2u modes creating higher frequency composites. Through the use of an optical parametric oscillator (OPO) to tune through the (1)B2u absorption band of liquid benzene, a stiffening (increase in energy) of the vibrational modes is observed as the excitation wavelength nears the (1)B2u absorption peak of the isolated molecule (vapor) phase. The strongest resonance amplitude observed is in the 2 × ν18 (e2g) mode, with nearly twice the intensity of the ring-breathing mode, ν2. Several overtones and combination modes, especially with ν2 (a1g), are also observed to resonate. Raman resonances on phonon-allowed excitations are narrow and permit the measurement of vibrations not Raman-active in the ground state. DA - 2016/2/4/ PY - 2016/2/4/ DO - 10.1021/acs.jpca.5b08159 VL - 120 IS - 4 SP - 503-506 SN - 1520-5215 ER - TY - JOUR TI - Pluses and minuses of ammonium and nitrate uptake and assimilation by phytoplankton and implications for productivity and community composition, with emphasis on nitrogen-enriched conditions AU - Glibert, Patricia M. AU - Wilkerson, Frances P. AU - Dugdale, Richard C. AU - Raven, John A. AU - Dupont, Christopher L. AU - Leavitt, Peter R. AU - Parker, Alexander E. AU - Burkholder, JoAnn M. AU - Kana, Todd M. T2 - LIMNOLOGY AND OCEANOGRAPHY AB - Anthropogenic activities are altering total nutrient loads to many estuaries and freshwaters, resulting in high loads not only of total nitrogen (N), but in some cases, of chemically reduced forms, notably . Long thought to be the preferred form of N for phytoplankton uptake, may actually suppress overall growth when concentrations are sufficiently high. has been well known to be inhibitory or repressive for uptake and assimilation, but the concentrations of that promote vs. repress uptake, assimilation, and growth in different phytoplankton groups and under different growth conditions are not well understood. Here, we review N metabolism first in a “generic” eukaryotic cell, and the contrasting metabolic pathways and regulation of and when these substrates are provided individually under equivalent growth conditions. Then the metabolic interactions of these substrates are described when both are provided together, emphasizing the cellular challenge of balancing nutrient acquisition with photosynthetic energy balance in dynamic environments. Conditions under which dissipatory pathways such as dissimilatory / reduction to and photorespiration that may lead to growth suppression are highlighted. While more is known about diatoms, taxon-specific differences in and metabolism that may contribute to changes in phytoplankton community composition when the composition of the N pool changes are presented. These relationships have important implications for harmful algal blooms, development of nutrient criteria for management, and modeling of nutrient uptake by phytoplankton, particularly in conditions where eutrophication is increasing and the redox state of N loads is changing. DA - 2016/1// PY - 2016/1// DO - 10.1002/lno.10203 VL - 61 IS - 1 SP - 165-197 SN - 1939-5590 ER - TY - JOUR TI - Incorporation of new particle formation and early growth treatments into WRF/Chem: Model improvement, evaluation, and impacts of anthropogenic aerosols over East Asia AU - Cai, Changjie AU - Zhang, Xin AU - Wang, Kai AU - Zhang, Yang AU - Wang, Litao AU - Zhang, Qiang AU - Duan, Fengkui AU - He, Kebin AU - Yu, Shao-Cai T2 - ATMOSPHERIC ENVIRONMENT AB - New particle formation (NPF) provides an important source of aerosol particles and cloud condensation nuclei, which may result in enhanced cloud droplet number concentration (CDNC) and cloud shortwave albedo. In this work, several nucleation parameterizations and one particle early growth parameterization are implemented into the online-coupled Weather Research and Forecasting model coupled with chemistry (WRF/Chem) to improve the model's capability in simulating NPF and early growth of ultrafine particles over East Asia. The default 8-bin over the size range of 39 nm–10 μm used in the Model for Simulating Aerosol Interactions and Chemistry aerosol module is expanded to the 12-bin over 1 nm–10 μm to explicitly track the formation and evolution of new particles. Although model biases remain in simulating H2SO4, condensation sink, growth rate, and formation rate, the evaluation of July 2008 simulation identifies a combination of three nucleation parameterizations (i.e., COMB) that can best represent the atmospheric nucleation processes in terms of both surface nucleation events and the resulting vertical distribution of ultrafine particle concentrations. COMB consists of a power law of Wang et al. (2011) based on activation theory for urban areas in planetary boundary layer (PBL), a power law of Boy et al. (2008) based on activation theory for non-urban areas in PBL, and the ion-mediated nucleation parameterization of YU10 for above PBL. The application and evaluation of the improved model with 12-bin and the COMB nucleation parameterization in East Asia during January, April, July, and October in 2001 show that the model has an overall reasonably good skill in reproducing most observed meteorological variables and surface and column chemical concentrations. Relatively large biases in simulated precipitation and wind speeds are due to inaccurate surface roughness and limitations in model treatments of cloud formation and aerosol-cloud-precipitation interactions. Large biases in the simulated surface concentrations of PM10, NOx, CO, SO2, and VOCs at some sites are due in part to possible underestimations of emissions and in part to inaccurate meteorological predictions. The simulations of 2001 show that anthropogenic aerosols can increase aerosol optical depth by 64.0–228.3%, CDNC by 40.2–76.4%, and cloud optical thickness by 14.3–25.3%; they can reduce surface net shortwave radiation by up to 42.5–52.8 W m−2, 2-m temperature by up to 0.34–0.83 °C, and PBL height by up to 76.8–125.9 m. Such effects are more significant than those previously reported for the U.S. and Europe. DA - 2016/1// PY - 2016/1// DO - 10.1016/j.atmosenv.2015.05.046 VL - 124 SP - 262-284 SN - 1873-2844 KW - New particle formation KW - Particle early growth KW - WRF/Chem KW - Aerosol direct effects KW - Aerosol indirect effects KW - East Asia ER - TY - JOUR TI - Exuberant granulation tissue response associated with Neobenedenia sp (Monogenea: Capsalidae) infestation in two cobia, Rachycentron canadum (Linnaeus) AU - Hurley-Sanders, J. AU - Harms, C. AU - Christiansen, E. AU - Clarke, E., III AU - Law, J. T2 - JOURNAL OF FISH DISEASES AB - Abstract Monogenean parasite infestations are common in captive marine teleosts, and are generally found on the skin and gills. This report describes an unusual pathological presentation of exuberant granulation tissue of the gills, suspected to be related to Neobenedenia infestation in two cobia housed together at a North Carolina aquarium. DA - 2016/3// PY - 2016/3// DO - 10.1111/jfd.12360 VL - 39 IS - 3 SP - 277-283 SN - 1365-2761 KW - granulation tissue KW - Neobenedenia KW - Rachycentron canadum ER - TY - JOUR TI - Chemistry supports the identification of gender-specific reproductive tissue in Tyrannosaurus rex AU - Schweitzer, M. H. AU - Zheng, W. X. AU - Zanno, L. AU - Werning, S. AU - Sugiyama, T. T2 - Scientific Reports DA - 2016/// PY - 2016/// VL - 6 ER - TY - JOUR TI - Application of online-coupled WRF/Chem-MADRID in East Asia: Model evaluation and climatic effects of anthropogenic aerosols AU - Liu, Xu-Yan AU - Zhang, Yang AU - Zhang, Qiang AU - He, Me-Bin T2 - ATMOSPHERIC ENVIRONMENT AB - The online-coupled Weather Research and Forecasting model with Chemistry with the Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (referred to as WRF/Chem-MADRID) is applied to simulate meteorological fields, air quality, and the direct and indirect effects of anthropogenic aerosols over East Asia in four months (January, April, July, and October) in 2008. Model evaluation against available surface and satellite measurements shows that despite some model biases, WRF/Chem-MADRID is able to reproduce reasonably well the spatial and seasonal variations of most meteorological fields and chemical concentrations. Large model biases for chemical concentrations are attributed to uncertainties in emissions and their spatial and vertical allocations, simulated meteorological fields, imperfectness of model representations of aerosol formation processes, uncertainties in the observations based on air pollution index, and the use of a coarse grid resolution. The results show that anthropogenic aerosols can reduce net shortwave flux at the surface by up to 40.5–57.2 W m−2, Temperature at 2-m by up to 0.5–0.8 °C, NO2 photolytic rates by up to 0.06–0.1 min−1 and the planetary boundary layer height by up to 83.6–130.4 m. Anthropogenic aerosols contribute to the number concentrations of aerosols by up to 6.2–8.6 × 104 cm−3 and the surface cloud concentration nuclei at a supersaturation of 0.5% by up to 1.0–1.6 × 104 cm−3. They increase the column cloud droplet number concentrations by up to 3.6–11.7 × 108 cm−2 and cloud optical thickness by up to 19.8–33.2. However, anthropogenic aerosols decrease daily precipitation in most areas by up to 3.9–18.6 mm during the 4 months. These results indicate the importance of anthropogenic aerosols in modulating regional climate changes in East Asia through aerosol direct and indirect effects, as well as the need to further improve the performance of online-coupled models. DA - 2016/1// PY - 2016/1// DO - 10.1016/j.atmosenv.2015.03.052 VL - 124 SP - 321-336 SN - 1873-2844 KW - Online-coupled model KW - WRF/Chem-MADRID KW - Model evaluation KW - Aerosol direct effects KW - Aerosol indirect effects KW - East Asia ER - TY - JOUR TI - Application of Weather Research and Forecasting Model with Chemistry (WRF/Chem) over northern China: Sensitivity study, comparative evaluation, and policy implications AU - Wang, Litao AU - Zhang, Yang AU - Wang, Kai AU - Zheng, Bo AU - Zhang, Qiang AU - Wei, Wei T2 - ATMOSPHERIC ENVIRONMENT AB - An extremely severe and persistent haze event occurred over the middle and eastern China in January 2013, with the record-breaking high concentrations of fine particulate matter (PM2.5). In this study, an online-coupled meteorology-air quality model, the Weather Research and Forecasting Model with Chemistry (WRF/Chem), is applied to simulate this pollution episode over East Asia and northern China at 36- and 12-km grid resolutions. A number of simulations are conducted to examine the sensitivities of the model predictions to various physical schemes. The results show that all simulations give similar predictions for temperature, wind speed, wind direction, and humidity, but large variations exist in the prediction for precipitation. The concentrations of PM2.5, particulate matter with aerodynamic diameter of 10 μm or less (PM10), sulfur dioxide (SO2), and nitrogen dioxide (NO2) are overpredicted partially due to the lack of wet scavenging by the chemistry-aerosol option with the 1999 version of the Statewide Air Pollution Research Center (SAPRC-99) mechanism with the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) and the Volatility Basis Set (VBS) for secondary organic aerosol formation. The optimal set of configurations with the best performance is the simulation with the Gorddard shortwave and RRTM longwave radiation schemes, the Purdue Lin microphysics scheme, the Kain-Fritsch cumulus scheme, and a nudging coefficient of 1 × 10−5 for water vapor mixing ratio. The emission sensitivity simulations show that the PM2.5 concentrations are most sensitive to nitrogen oxide (NOx) and SO2 emissions in northern China, but to NOx and ammonia (NH3) emissions in southern China. 30% NOx emission reductions may result in an increase in PM2.5 concentrations in northern China because of the NH3-rich and volatile organic compound (VOC) limited conditions over this area. VOC emission reductions will lead to a decrease in PM2.5 concentrations in eastern China. However, 30% reductions in the emissions of SO2, NOx, NH3, and VOC, individually or collectively, are insufficient to effectively mitigate the severe pollution over northern China. More aggressive emission controls, which needs to be identified in further studies, are needed in this area to reach the objective of 25% PM2.5 concentration reduction in 2017 proposed in the Action Plan for Air Pollution Prevention and Control by the State Council in 2013. DA - 2016/1// PY - 2016/1// DO - 10.1016/j.atmosenv.2014.12.052 VL - 124 SP - 337-350 SN - 1873-2844 KW - WRF/Chem KW - PM2.5 KW - Regional haze KW - Northern China KW - Comparative evaluation KW - Sensitivity study ER - TY - JOUR TI - Application of WRF/Chem over East Asia: Part II. Model improvement and sensitivity simulations AU - Zhang, Yang AU - Zhang, Xin AU - Wang, Kai AU - Zhang, Qiang AU - Duan, Fengkui AU - He, Kebin T2 - ATMOSPHERIC ENVIRONMENT AB - To address the problems and limitations identified through a comprehensive evaluation in Part I paper, several modifications are made in model inputs, treatments, and configurations and sensitivity simulations with improved model inputs and treatments are performed in this Part II paper. The use of reinitialization of meteorological variables reduces the biases and increases the spatial correlations in simulated temperature at 2-m (T2), specific humidity at 2-m (Q2), wind speed at 10-m (WS10), and precipitation (Precip). The use of a revised surface drag parameterization further reduces the biases in simulated WS10. The adjustment of only the magnitudes of anthropogenic emissions in the surface layer does not help improve overall model performance, whereas the adjustment of both the magnitudes and vertical distributions of anthropogenic emissions shows moderate to large improvement in simulated surface concentrations and column mass abundances of species in terms of domain mean performance statistics, hourly and monthly mean concentrations, and vertical profiles of concentrations at individual sites. The revised and more advanced dust emission schemes can help improve PM predictions. Using revised upper boundary conditions for O3 significantly improves the column O3 abundances. Using a simple SOA formation module further improves the predictions of organic carbon and PM2.5. The sensitivity simulation that combines all above model improvements greatly improves the overall model performance. For example, the sensitivity simulation gives the normalized mean biases (NMBs) of −6.1% to 23.8% for T2, 2.7–13.8% for Q2, 22.5–47.6% for WS10, and −9.1% to 15.6% for Precip, comparing to −9.8% to 75.6% for T2, 0.4–23.4% for Q2, 66.5–101.0% for WS10, and 11.4%–92.7% for Precip from the original simulation without those improvements. It also gives the NMBs for surface predictions of −68.2% to −3.7% for SO2, −73.8% to −20.6% for NO2, −8.8%–128.7% for O3, −61.4% to −26.5% for PM2.5, and −64.0% to 7.2% for PM10, comparing to −84.2% to −44.5% for SO2, −88.1% to −44.0% for NO2, −11.0%–160.3% for O3, −63.9% to −25.2% for PM2.5, and −68.9%–33.3% for PM10 from the original simulation. The improved WRF/Chem is applied to estimate the impact of anthropogenic aerosols on regional climate and air quality in East Asia. Anthropogenic aerosols can increase cloud condensation nuclei, aerosol optical depth, cloud droplet number concentrations, and cloud optical depth. They can decrease surface net radiation, temperature at 2-m, wind speed at 10-m, planetary boundary layer height, and precipitation through various direct and indirect effects. These changes in turn lead to changes in chemical predictions in a variety of ways. DA - 2016/1// PY - 2016/1// DO - 10.1016/j.atmosenv.2015.07.023 VL - 124 SP - 301-320 SN - 1873-2844 KW - WRF/Chem KW - Model improvement KW - Sensitivity simulation KW - Aerosol direct effects KW - Aerosol indirect effects KW - East Asia ER - TY - JOUR TI - Application of WRF/Chem over East Asia: Part I. Model evaluation and intercomparison with MM5/CMAQ AU - Zhang, Yang AU - Zhang, Xin AU - Wang, Litao AU - Zhang, Qiang AU - Duan, Fengkui AU - He, Kebin T2 - ATMOSPHERIC ENVIRONMENT AB - In this work, the application of the online-coupled Weather Research and Forecasting model with chemistry (WRF/Chem) version 3.3.1 is evaluated over East Asia for January, April, July, and October 2005 and compared with results from a previous application of an offline model system, i.e., the Mesoscale Model and Community Multiple Air Quality modeling system (MM5/CMAQ). The evaluation of WRF/Chem is performed using multiple observational datasets from satellites and surface networks in mainland China, Hong Kong, Taiwan, and Japan. WRF/Chem simulates well specific humidity (Q2) and downward longwave and shortwave radiation (GLW and GSW) with normalized mean biases (NMBs) within 24%, but shows moderate to large biases for temperature at 2-m (T2) (NMBs of −9.8% to 75.6%) and precipitation (NMBs of 11.4–92.7%) for some months, and wind speed at 10-m (WS10) (NMBs of 66.5–101%), for all months, indicating some limitations in the YSU planetary boundary layer scheme, the Purdue Lin cloud microphysics, and the Grell–Devenyi ensemble scheme. WRF/Chem can simulate the column abundances of gases reasonably well with NMBs within 30% for most months but moderately to significantly underpredicts the surface concentrations of major species at all sites in nearly all months with NMBs of −72% to −53.8% for CO, −99.4% to −61.7% for NOx, −84.2% to −44.5% for SO2, −63.9% to −25.2% for PM2.5, and −68.9% to 33.3% for PM10, and aerosol optical depth in all months except for October with NMBs of −38.7% to −16.2%. The model significantly overpredicts surface concentrations of O3 at most sites in nearly all months with NMBs of up to 160.3% and NO3- at the Tsinghua site in all months. Possible reasons for large underpredictions include underestimations in the anthropogenic emissions of CO, SO2, and primary aerosol, inappropriate vertical distributions of emissions of SO2 and NO2, uncertainties in upper boundary conditions (e.g., for O3 and CO), missing or inaccurate model representations (e.g., secondary organic aerosol formation, gas/particle partitioning, dust emissions, dry and wet deposition), and inaccurate meteorological fields (e.g., overpredictions in WS10 and precipitation, but underpredictions in T2), as well as the large uncertainties in satellite retrievals (e.g., for column SO2). Comparing to MM5, WRF generally gives worse performance in meteorological predictions, in particular, T2, WS10, GSW, GLW, and cloud fraction in all months, as well as Q2 and precipitation in January and October, due to limitations in the above physics schemes or parameterizations. Comparing to CMAQ, WRF/Chem performs better for surface CO, O3, and PM10 concentrations at most sites in most months, column CO and SO2 abundances, and AOD. It, however, gives poorer performance for surface NOx concentrations at most sites in most months, surface SO2 concentrations at all sites in all months, and column NO2 abundances in January and April. WRF/Chem also gives lower concentrations of most secondary PM and black carbon. Those differences in results are attributed to differences in simulated meteorology, gas-phase chemistry, aerosol thermodynamic and dynamic treatments, dust and sea salt emissions, and wet and dry deposition treatments in both models. DA - 2016/1// PY - 2016/1// DO - 10.1016/j.atmosenv.2015.07.022 VL - 124 SP - 285-300 SN - 1873-2844 KW - WRF/Chem KW - MM5/CMAQ KW - East Asia KW - Model evaluation KW - Model intercomparison ER - TY - JOUR TI - The Relationship between the Madden-Julian Oscillation (MJO) and Southeastern New England Snowfall AU - Klotzbach, Philip J. AU - Oliver, Eric C. J. AU - Leeper, Ronald D. AU - Schreck, Carl J., III T2 - MONTHLY WEATHER REVIEW AB - Abstract The winter of 2014/15 brought record snow totals to portions of southeastern New England. Additionally, over 90% of Boston Logan Airport snowfall during the winter fell during phases 7 and 8 of the Madden–Julian oscillation (MJO) index. This motivated the authors to investigate potential connections between intense southeastern New England snowstorms and the MJO in the historical record. It was found that southeastern New England snowfall, measured since the 1930s at several stations in the region, recorded higher than average winter snowfalls when enhanced MJO convection was located over the western Pacific and the Western Hemisphere (phases 7–8). Similarly, snowfall was suppressed when enhanced MJO convection was located over the Maritime Continent (phases 4–5). The MJO also modulates the frequency of nor’easters, which contribute the majority of New England’s snowfall, as measured by reanalysis-derived cyclone tracks. These tracks were more numerous during the same MJO phases that lead to enhanced snowfall, and they were less common during phases with less snowfall. DA - 2016/4// PY - 2016/4// DO - 10.1175/mwr-d-15-0434.1 VL - 144 IS - 4 SP - 1355-1362 SN - 1520-0493 KW - Snowfall KW - Snow KW - Atm/Ocean Structure/ Phenomena KW - Madden-Julian oscillation KW - Extratropical cyclones ER - TY - JOUR TI - Surfactant effect on cloud condensation nuclei for two-component internally mixed aerosols AU - Petters, Sarah Suda AU - Petters, Markus Dirk T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Abstract This work presents experimental data on the cloud condensation nuclei (CCN) activity of two‐component mixtures containing surfactants. Nine binary systems were tested combining strong ionic (sodium dodecyl sulfate) and nonionic surfactants (Zonyl FS‐300 and Triton X‐100) with nonsurfactant compounds (glucose, ammonium sulfate, or sodium chloride). Control tests were performed for systems combining organic (glucose) and inorganic compounds (ammonium sulfate or sodium chloride). Results show that CCN activity deviates strongly relative to predictions made from measurements of bulk surface tension. Köhler theory accounting for surface tension reduction and surface partitioning underpredicts the CCN activity of particles containing Zonyl FS‐300 and Triton X‐100. Partitioning theory better describes data for Zonyl FS‐300 and Triton X‐100 when limiting surface adsorption to 1.5 monolayers of the growing drop. Deviations from predictions were observed. Likely explanations include solute‐solute interactions and nonspherical particle shape. The findings presented here examine in detail the perturbation of CCN activity by surfactants and may offer insight into both the success and limitations of physical models describing CCN activity of surface active molecules. DA - 2016/2/27/ PY - 2016/2/27/ DO - 10.1002/2015jd024090 VL - 121 IS - 4 SP - 1878-1895 SN - 2169-8996 KW - organic aerosols KW - cloud condensation nuclei KW - surfactants KW - surface-bulk partitioning KW - Kohler theory KW - aerosol-cloud interactions ER - TY - JOUR TI - Stable isotope signatures of seasonal precipitation on the Pacific coast of central Panama AU - Kern, Zoltan AU - Harmon, Russell S. AU - Forizs, Istvan T2 - ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES AB - As calculated from data archived in the IAEA-WMO Global Network of Isotopes in Precipitation programme, the amount-weighted local meteoric water line for the Pacific coast of central Panama is: δ(2)H = 7.63(±0.08) × δ(18)O + 6.51(±0.49). Amount-weighted mean isotopic values were regressed against the sea surface temperature (SST) fields of the adjacent tropical oceans. A negative correlation of precipitation isotope composition with Caribbean SSTs is observed only for the early wet season (May-June), whilst the mid-summer dry period is characterized by positive correlation with eastern Pacific SSTs, similar to the late wet season (October-November). The negative response of May-June rainfall isotopic composition to Caribbean SSTs is explained by a SST-mediated change in stratiform rain fraction from organized convective systems proximal to the Inter Tropical Convergence Zone (ITCZ). The positive correlation for the rest of the wet season, when the organized convective zone of ITCZ and its attached stratiform belt are distant from the Pacific coast of Panama, is interpreted as simple evaporative temperature effect on isotopic fractionation. DA - 2016/3/3/ PY - 2016/3/3/ DO - 10.1080/10256016.2015.1016021 VL - 52 IS - 1-2 SP - 128-140 SN - 1477-2639 KW - Panama KW - evaporation KW - tropical hydrometeorology KW - hydrogen-2 KW - oxygen-18 KW - isotope hydrology KW - precipitation KW - ocean KW - meteoric water line KW - isotope fractionation ER - TY - JOUR TI - Source-to-sink sedimentary systems and global carbon burial: A river runs through it AU - Leithold, Elana L. AU - Blair, Neal E. AU - Wegmann, Karl W. T2 - EARTH-SCIENCE REVIEWS AB - Source to sink sedimentary systems are important settings of carbon cycling, serving as sites of carbon transfer between terrestrial and marine reservoirs, and as the primary locations for organic carbon burial on Earth. The age and character of the carbon that is buried at the terminal ends of these systems reflects the sources and transformations of the organic carbon (OC) throughout their linked terrestrial and marine segments. Profound differences are observed between large passive and small active margin systems. Large passive margin systems are characterized by large floodplains and relatively broad shelves where OC has protracted exposure to oxidants. Rapid burial in prograding, subaqueous deltaic clinoforms or bypass to submarine fans, however, leads to high burial efficiency of terrestrial biospheric OC in some passive margin settings. The OC in small active margin systems, in contrast, follows relatively short pathways from headwaters to seabed. This rapid transit, facilitated by the important role of storm-driven transport in such settings, can lead to high OC burial efficiencies. The study of OC sources and transformations in contemporaneous source to sink sedimentary systems informs interpretations about the systems in which OC was buried in the geologic past, their stratigraphic records of environmental change, and their potential to produce petroleum resources. DA - 2016/2// PY - 2016/2// DO - 10.1016/j.earscirev.2015.10.011 VL - 153 SP - 30-42 SN - 1872-6828 KW - Source to sink KW - Organic carbon KW - Carbon cycle ER - TY - JOUR TI - Soundscapes and larval settlement: larval bivalve responses to habitat-associated underwater sounds AU - Eggleston, D. B. AU - Lillis, A. AU - Bohnenstiehl, D. R. T2 - Effects of noise on aquatic life ii DA - 2016/// PY - 2016/// VL - 875 SP - 255-263 ER - TY - JOUR TI - Soundscapes and larval settlement: Characterizing the stimulus from a larval perspective AU - Lillis, A. AU - Eggleston, D. B. AU - Bohnenstiehl, D. R. T2 - Effects of noise on aquatic life ii DA - 2016/// PY - 2016/// VL - 875 SP - 637-645 ER - TY - JOUR TI - Evolution of the Jiuduansha wetland and the impact of navigation works in the Yangtze Estuary, China AU - Li, Xing AU - Liu, J. Paul AU - Tian, Bo T2 - Geomorphology AB - The estuarine wetlands in the Yangtze Estuary face increasing threats due to large-scale engineering projects and huge land requirements. As a Wetland National Nature Reserve and important stopover site for migratory shorebirds of the East Asian–Australasian Flyway, the Jiuduansha wetland, one of four main islands in the estuary, is of both national and international importance. Since 1998 the previously undisturbed wetland has been considerably modified by the adjacent Deep-water Navigation Channel project (DNC). In order to understand the role of the DNC for the evolution of the Jiuduansha wetland, we performed a diagnostic study from multiple perspectives, including deposition rate, area change, evolution track, geometric characteristics, and geomorphological change. By coupling GIS, geostatistics, and remote sensing techniques, this study demonstrates the impact of the DNC on the Jiuduansha wetland in a spatially explicit way. Multi-temporal bathymetric maps and Landsat images from before and after the DNC was constructed were adopted to conduct our study. We find that deposition has occurred in most parts of the wetland over the past almost 30 years, accounting for 67.3% of the total area. However, over 40% of the study area shows a decreasing trend in deposition rate. The spatial distribution of deposition–erosion patterns is closely linked to the DNC. We also find that the DNC has substantial effects on the evolution of the Jiuduansha wetland. The 0, 2, and 5 m isobaths in the Jiuduansha Shoal (JDS), as well as in the Jiangya Shoal (JYS), the Upper Shoal (US) and the Middle-Lower Shoal (MLS), show different response patterns to the DNC. Specifically, the south training jetty of the DNC has an “adsorption effect” on the JDS above the 2 m isobaths intersecting with it. As a result, the evolution track, geometric and geomorphological characteristics of the JDS were markedly altered in the short term. Our comprehensive analysis suggests that in the future, the JDS will become more elongated in both the upstream and downstream direction along the south training jetty, and that the south side of the JDS will be eroded. DA - 2016/1// PY - 2016/1// DO - 10.1016/J.GEOMORPH.2015.10.031 VL - 253 SP - 328-339 J2 - Geomorphology LA - en OP - SN - 0169-555X UR - http://dx.doi.org/10.1016/J.GEOMORPH.2015.10.031 DB - Crossref KW - Estuarine wetland KW - Engineering works KW - Geomorphological change KW - Geometric characteristics KW - Geostatistics KW - Remote sensing ER - TY - JOUR TI - Environmental effects on elemental signatures in eastern oyster Crassostrea virginica shells: using geochemical tagging to assess population connectivity AU - Kroll, Ian R. AU - Poray, Abigail K. AU - Puckett, Brandon J. AU - Eggleston, David B. AU - Fodrie, F. Joel T2 - MARINE ECOLOGY PROGRESS SERIES AB - MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 543:173-186 (2016) - DOI: https://doi.org/10.3354/meps11549 Environmental effects on elemental signatures in eastern oyster Crassostrea virginica shells: using geochemical tagging to assess population connectivity Ian R. Kroll1,2,*, Abigail K. Poray1, Brandon J. Puckett3,4, David B. Eggleston3, F. Joel Fodrie1,2 1Institute of Marine Sciences, University of North Carolina at Chapel Hill, 3437 Arendell Street, Morehead City, NC 28557, USA 2Department of Marine Sciences, University of North Carolina at Chapel Hill, 3202 Venable Hall, Chapel Hill, NC 27599, USA 3Center for Marine Science and Technology, North Carolina State University, 303 College Circle, Morehead City, NC 28557, USA 4Present address: North Carolina National Estuarine Research Reserve, 101 Pivers Island Road, Beaufort, NC 28516, USA *Corresponding author: ikroll@live.unc.edu ABSTRACT: We evaluated the utility of geochemical tagging methods to discern larval connectivity among an invertebrate metapopulation within a large (~5000 km2) temperate estuary. Specifically, we examined how estuarine-scale gradients in temperatures (21° to 26.5°C), salinities (12.5 to 20 ppt), and trace metal concentrations (ambient, +16 ppb Mn and 0.16 ppb Pb, or +32 ppb Mn and 0.32 ppb Pb) affect Crassostrea virginica larval-shell signatures of Mn, Sr, Ba, and Pb in controlled mesocosms. We also utilized field-collected, newly settled oysters across Pamlico Sound, NC, USA, to explore signature variability among natural temperature and salinity gradients and examine the spatial resolution at which geochemical signatures can be used to discriminate between collection regions. Mesocosm experiments revealed environmentally and statistically significant interactive effects between temperature and salinity on elemental ratios in larval oyster shells, favoring higher Sr concentrations in cooler, fresher water, but no effects of these factors on Ba signatures. Mesocosm trials also showed increased Mn signatures in larval shell following from spiking mesocosms with Mn solutions; however, this relationship did not hold for Pb following analogous elemental spikes. Our field collections of recent settlers showed similar patterns of high Sr at relatively low salinities and temperatures, without clear environmental gradients for Ba. Overall, we found that across regional (35 km) spatial scales, environmental variables, such as salinity and temperature, can generate distinct multi-elemental signatures between putative natal sites. However, if sites are close together or located in similar environments, discrimination among sites appears greatly reduced. We suggest that geochemical tagging provides a promising approach for characterizing larval connectivity among subpopulations within whole-estuarine systems. KEY WORDS: Bivalve larvae · Connectivity · Crassostrea virginica · Geochemical tagging · Larval dispersal · Laser ablation ICP-MS · Oysters · Salinity · Temperature Full text in pdf format PreviousNextCite this article as: Kroll IR, Poray AK, Puckett BJ, Eggleston DB, Fodrie FJ (2016) Environmental effects on elemental signatures in eastern oyster Crassostrea virginica shells: using geochemical tagging to assess population connectivity. Mar Ecol Prog Ser 543:173-186. https://doi.org/10.3354/meps11549 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 543. Online publication date: February 03, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research. DA - 2016/2/3/ PY - 2016/2/3/ DO - 10.3354/meps11549 VL - 543 SP - 173-186 SN - 1616-1599 KW - Bivalve larvae KW - Connectivity KW - Crassostrea virginica KW - Geochemical tagging KW - Larval dispersal KW - Laser ablation ICP-MS KW - Oysters KW - Salinity KW - Temperature ER - TY - JOUR TI - Dispersion of a tracer in the deep Gulf of Mexico AU - Ledwell, James R. AU - He, Ruoying AU - Xue, Zuo AU - DiMarco, Steven F. AU - Spencer, Laura J. AU - Chapman, Piers T2 - JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS AB - Abstract A 25 km streak of CF 3 SF 5 was released on an isopycnal surface approximately 1100 m deep, and 150 m above the bottom, along the continental slope of the northern Gulf of Mexico, to study stirring and mixing of a passive tracer. The location and depth of the release were near those of the deep hydrocarbon plume resulting from the 2010 Deepwater Horizon oil well rupture. The tracer was sampled between 5 and 12 days after release, and again 4 and 12 months after release. The tracer moved along the slope at first but gradually moved into the interior of the Gulf. Diapycnal spreading of the patch during the first 4 months was much faster than it was between 4 and 12 months, indicating that mixing was greatly enhanced over the slope. The rate of lateral homogenization of the tracer was much greater than observed in similar experiments in the open ocean, again possibly enhanced near the slope. Maximum concentrations found in the surveys had fallen by factors of 10 4 , 10 7 , and 10 8 , at 1 week, 4 months, and 12 months, respectively, compared with those estimated for the initial tracer streak. A regional ocean model was used to simulate the tracer field and help interpret its dispersion and temporal evolution. Model‐data comparisons show that the model simulation was able to replicate statistics of the observed tracer distribution that would be important in assessing the impact of oil releases in the middepth Gulf. DA - 2016/2// PY - 2016/2// DO - 10.1002/2015jc011405 VL - 121 IS - 2 SP - 1110-1132 SN - 2169-9291 KW - mixing KW - tracer KW - Gulf of Mexico KW - turbulence KW - circulation ER - TY - JOUR TI - A source-to-sink perspective of the Waipaoa River margin AU - Kuehl, Steven A. AU - Alexander, Clark R. AU - Blair, Neal E. AU - Harris, Courtney K. AU - Marsaglia, Kathleen M. AU - Ogston, Andrea S. AU - Orpin, Alan R. AU - Roering, Joshua J. AU - Bever, Aaron J. AU - Bilderback, Eric L. AU - Carter, Lionel AU - Cerovski-Darriau, Corina AU - Childress, Laurel B. AU - Corbett, D. Reide AU - Hale, Richard P. AU - Leithold, Elana L. AU - Litchfield, Nicola AU - Moriarty, Julia M. AU - Page, Mike J. AU - Pierce, Lila E. R. AU - Upton, Phaedra AU - Walsh, John P. T2 - EARTH-SCIENCE REVIEWS AB - A fundamental goal of the Earth Science community is to understand how perturbations on Earth's surface are preserved in the stratigraphic record. Recent Source to Sink (S2S) studies of the Waipaoa Sedimentary System (WSS), New Zealand, are synthesized herein to provide a holistic perspective of the processes that generate, transport and preserve sedimentary strata and organic carbon on the Waipaoa margin in the late Quaternary. Rapid uplift associated with subduction processes and weak sedimentary units have conspired to generate rapid rates of incision and erosion in the Waipaoa catchment since the Last Glacial Maximum (LGM). We show that although much of the sediment exported offshore during this time interval originated from valley excavation, a substantial portion emanated from hillslopes, mostly through deep-seated landslide and earthflow processes that were vigorous during periods of rapid fluvial incision just prior to the Pleistocene–Holocene transition. Lacustrine sediments deposited in naturally-dammed 7-ky-old Lake Tutira provide a record of Holocene environmental controls on upper catchment sedimentation in the WSS, with 1400 storms identified. Storm frequency is modulated by the waxing and waning of atmospheric teleconnections between the tropics and Antarctica. Furthermore, clear long-term changes in sediment yield are evident from the Lake Tutira record following human settlement as conversion to pasture is accompanied by a 3-fold increase in the long-term lake sediment accumulation rate. Whereas there is ample evidence that Waipaoa River flood deposits are routinely deposited offshore in the sheltered confines of Poverty Bay, over the longer term, waves and currents subsequently resuspend and transport these deposits both landward (sandy fraction) and seaward (finer fraction). Thus, the timing of sediment supply to areas of net sediment accumulation is more often driven by wave events that are not associated with river flooding. Therefore, we conclude that asynchronicity of river-sediment delivery and of wave resuspension in most instances precludes the direct preservation of flood events in the stratigraphic record of the Waipaoa Shelf. Over the longer term, the sediment package preserved on the shelf and slope since the LGM can be explained in large measure by sequence-stratigraphic models forced by varying sea level and ongoing tectonic deformation of the margin. As sea level rose, sediment supply to the slope was reduced by about a factor of 5 due to shelf trapping. Despite this reduction, turbidites are found at similar frequency throughout the LGM–Present, as the dominant trigger appears to be subduction earthquakes, with large ones having a return interval of about 200 ± 100 years. Sediment-budget exercises that consider both modern (river discharge versus centennial accumulation rates) and post-LGM (terrestrial production versus offshore isopachs) mass balances indicate that about half of the total sediment production from the Waipaoa escapes the study area. Moreover, a coupled sediment transport-hydrodynamic model and observations of textural trends on the shelf indicate that a large fraction of the sediment is carried outside the study area along the shelf to the northeast by the river plume or by combined current/wave activity. Therefore, we conclude that the WSS is an open system with sediment escape from the present day through the LGM. The organic matter associated with sediment as it moves from upland source to marine sink is a product of particle history, and provides a record of materials that have cycled over timescales of days to millions of years. The ubiquity of fossil Organic Carbon (OC) in both the terrestrial and marine realms of the Waipaoa attests both to the chronic nature of its source, crumbling mudstones further destabilized by land use, and its biogeochemical recalcitrance. Modern OC persists by virtue of its continual production along the S2S transit, and is buried and preserved within the adjacent marine depocenters. The Waipaoa contrasts with dispersal systems on wide, energetic shelves (e.g., the Amazon and Fly Rivers) where sediment is extensively refluxed in oxygenated overlying water resulting in the biogeochemical incineration of particulate OC. The Waipaoa, like other small mountainous rivers on active margins, exhibits a high riverine OC preservation efficiency (> 50%) in its marine depocenters because of the relatively rapid, event-driven accumulation of sediment. DA - 2016/2// PY - 2016/2// DO - 10.1016/j.earscirev.2015.10.001 VL - 153 SP - 301-334 SN - 1872-6828 KW - Waipaoa River KW - New Zealand KW - Continental margin KW - Sedimentology KW - Stratigraphy KW - Landscape evolution KW - Sediment transport KW - Carbon cycle ER - TY - JOUR TI - A high order finite difference solver for massively parallel simulations of stably stratified turbulent channel flows AU - He, P. T2 - Computers & Fluids DA - 2016/// PY - 2016/// VL - 127 SP - 161-173 ER - TY - JOUR TI - Monthly land cover-specific evapotranspiration models derived from global eddy flux measurements and remote sensing data AU - Fang, Yuan AU - Sun, Ge AU - Caldwell, Peter AU - McNulty, Steven G. AU - Noormets, Asko AU - Domec, Jean-Christophe AU - King, John AU - Zhang, Zhiqiang AU - Zhang, Xudong AU - Lin, Guanghui AU - Zhou, Guangsheng AU - Xiao, Jingfeng AU - Chen, Jiquan T2 - ECOHYDROLOGY AB - Abstract Evapotranspiration (ET) is arguably the most uncertain ecohydrologic variable for quantifying watershed water budgets. Although numerous ET and hydrological models exist, accurately predicting the effects of global change on water use and availability remains challenging because of model deficiency and/or a lack of input parameters. The objective of this study was to create a new set of monthly ET models that can better quantify landscape‐level ET with readily available meteorological and biophysical information. We integrated eddy covariance flux measurements from over 200 sites, multiple year remote sensing products from the Moderate Resolution Imaging Spectroradiometer (MODIS), and statistical modelling. Through examining the key biophysical controls on ET by land cover type (i.e. shrubland, cropland, deciduous forest, evergreen forest, mixed forest, grassland, and savannas), we created unique ET regression models for each land cover type using different combinations of biophysical independent factors. Leaf area index and net radiation explained most of the variability of observed ET for shrubland, cropland, grassland, savannas, and evergreen forest ecosystems. In contrast, potential ET (PET) as estimated by the temperature‐based Hamon method was most useful for estimating monthly ET for deciduous and mixed forests. The more data‐demanding PET method, FAO reference ET model, had similar power as the simpler Hamon PET method for estimating actual ET. We developed three sets of monthly ET models by land cover type for different practical applications with different data availability. Our models may be used to improve water balance estimates for large basins or regions with mixed land cover types. Copyright © 2015 John Wiley & Sons, Ltd. DA - 2016/3// PY - 2016/3// DO - 10.1002/eco.1629 VL - 9 IS - 2 SP - 248-266 SN - 1936-0592 KW - eddy covariance flux KW - evapotranspiration KW - ecosystem modelling KW - ecohydrology KW - FLUXNET ER - TY - JOUR TI - Microwave preservation method for DMSP, DMSO, and acrylate in unfiltered seawater and phytoplankton culture samples AU - Kinsey, Joanna D. AU - Kieber, David J. T2 - LIMNOLOGY AND OCEANOGRAPHY-METHODS AB - Abstract A microwave‐preservation method was developed to quantify total dimethylsulfoniopropionate (DMSP T ), dimethylsulfoxide (DMSO T ), and acrylate (acrylate T ) concentrations in unfiltered samples to alleviate problems associated with the acidification method when applied to samples containing Phaeocystis . Microwave‐ and acid‐preservation methods were compared using batch cultures of Phaeocystis antarctica and 11 other marine phytoplankton species for DMSP T , batch P. antarctica cultures for DMSO T and acrylate T , and unfiltered Delaware Estuary water samples for DMSP T to demonstrate the general applicability of this method. Acidification of P. antarctica culture samples resulted in the underestimation of DMSP T (42–69%) and overestimation of dimethylsulfide (DMS) (2156–3819%), DMSO T (9–101%), and acrylate T (71–249%). By comparison, DMSP T concentrations in microwaved samples agreed with non‐microwaved, non‐acidified controls. In contrast to P. antarctica results, the microwave‐ and acid‐preservation methods yielded DMSP T concentrations that were statistically indistinguishable for 11 other marine phytoplankton species and Delaware Estuary samples. Unfiltered samples stored frozen following microwave treatment or stored at room temperature if acidified after the microwaving step, resulted in no change in DMSP T or acrylate T ; DMSO T concentrations increased slightly (∼ 15%) when they were not sparged to remove DMS prior to acidification and room temperature storage. Based on these findings, we propose microwaving small sample volumes (≤ 7 mL) of unfiltered seawater or culture samples as a general approach to preserve samples for subsequent DMSP T , DMSO T , and acrylate T analyses, especially when the phytoplankton composition of the samples is unknown. DA - 2016/3// PY - 2016/3// DO - 10.1002/lom3.10081 VL - 14 IS - 3 SP - 196-209 SN - 1541-5856 ER -