TY - JOUR TI - Chemical mixing model of streamflow generation at La Selva Biological Station, Costa Rica AU - Genereux, David AU - Pringle, Catherine T2 - Journal of Hydrology AB - La Selva Biological Station occupies an area of lowland tropical rainforest in central Costa Rica. Sodium and chloride data were used to quantify the mixing proportions of local runoff and geothermal groundwater at several sites throughout the stream channel system in late April, at the end of the dry season. The fraction of streamflow accounted for by geothermal groundwater varied spatially between 0 and 0.85, indicating a significant contribution to streamflow and to stream solute loads from geothermal groundwater at some sites. In general, higher inputs of geothermal groundwater were found at lower elevations. Over half the flow from one basin (the Salto) was due to geothermal groundwater, suggesting a minimum annual runoff of about 0.7 m of geothermal groundwater from this basin. A plot of NaCl vs. fraction of geothermal groundwater revealed watershed-scale chemical differences between the two major drainage systems (the Sura and the Salto), differences that were not apparent from a traditional two-solute plot of Cl vs. Na concentration. A small (21 mm) storm produced relatively little change in mixing proportions, as most throughfall was apparently retained in the relatively dry soils. DA - 1997/12// PY - 1997/12// DO - 10.1016/S0022-1694(96)03333-1 VL - 199 IS - 3-4 SP - 319-330 J2 - Journal of Hydrology LA - en OP - SN - 0022-1694 UR - http://dx.doi.org/10.1016/S0022-1694(96)03333-1 DB - Crossref ER - TY - JOUR TI - Forecasting the Next Century’s Weather AU - Robinson, W.A. T2 - IEEE Spectrum AB - These three volumes (Working Groups I,II, and III), comprising nearly 1900 pages, are better known as the IPCC reports, IPCC standing for Intergovernmental Panel on Climate Change. Books of this technical content and heft written by large international committees rarely arouse much excitement. The IPCC was established by the World Meteorological Organization and the United Nations Environment Program in 1988 to assess the science of human-induced climate change, the impacts of such change, and how these impacts could be reduced.he three volumes of Climate Change 1995 describe the state of the art in modeling climate change and predicting and dealing with its effects on society. The completeness of these books makes them a valuable reference for the teacher or researcher and a good place to begin a search of the current literature. The same completeness, however, keeps these volumes from being good places to read about the climate problem. The summaries for policy makers are too brief, the technical summaries make too many references to previous IPCC reports, and the chapters themselves are far too detailed. For the sake of completeness there are discussions of very minor effects on the climate—for example, from obscure greenhouse gases, present in only trivial concentrations that are dwarfed by uncertainties in fundamental processes. In most places, the writing has been by committee, and anything resembling style has been expunged. DA - 1997/1// PY - 1997/1// DO - 10.1109/mspec.1997.560635 VL - 34 IS - 1 SP - 10–14 ER - TY - JOUR TI - The modeled atmospheric response to midlatitude SST anomalies and its dependence on background circulation states AU - Peng, SL AU - Robinson, WA AU - Hoerling, MP T2 - Journal of Climate AB - The atmospheric response to a midlatitude SST anomaly in the North Pacific and its dependence on background flow are examined in a GCM. Experiments are conducted using the same warm SST anomalies but two different model states: perpetual January and perpetual February. The atmospheric responses to the SST anomalies are statistically significant in both January and February but are completely different. The anomalous circulation in January is characterized by a trough decaying with height immediately downstream of the SST anomalies. In February, the anomalous circulation is dominated by a downstream ridge growing with height. The patterns of the anomalous heights in the two months are nearly orthogonal. Vorticity and thermodynamic budgets are diagnosed to illustrate how the anomalous circulations are maintained. Over the SST anomalies, low-level convergence and ascent are observed in both months. In January the anomalous convergence is balanced by a residual due primarily to the forcing by submonthly transients. In February the convergence is balanced by the advection of planetary vorticity. Analysis of the thermodynamic budget indicates that the intensity of the mean meridional wind downstream of the SST anomalies plays a critical role in determining the nature of the responses in the two months. The “warm SST-ridge” type of response is favored when the background meridional flow is relatively weak. These results demonstrate that the atmospheric response to a midlatitude SST anomaly is strongly dependent on the background flow. DA - 1997/// PY - 1997/// DO - 10.1175/1520-0442(1997)010<0971:TMARTM>2.0.CO;2 VL - 10 IS - 5 SP - 971-987 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:A1997XB77300008&KeyUID=WOS:A1997XB77300008 ER - TY - JOUR TI - On the dynamics of the observed zonal index AU - Robinson, WA AU - Weickmann, KM AU - SOC, AMER METEOROL T2 - 11th Conference on Atmospheric and Oceanic Fluid Dynamics DA - 1997/// PY - 1997/// SP - 275-276 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000071010100083&KeyUID=WOS:000071010100083 ER - TY - JOUR TI - Low frequency variability in a stochastically forced barotropic model AU - Huang, HP AU - Robinson, WA AU - SOC, AMER METEOROL T2 - 11th Conference on Atmospheric and Oceanic Fluid Dynamics DA - 1997/// PY - 1997/// SP - 328-331 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000071010100101&KeyUID=WOS:000071010100101 ER - TY - JOUR TI - Dissipation dependence of the jet latitude AU - Robinson, WA T2 - Journal of Climate AB - Zonally averaged flows in general circulation models exhibit strong sensitivity to the strength of the surface friction, subgrid-scale diffusion, and gravity wave drag. A commonly observed effect is that the midlatitude jets shift poleward as the drag on the zonal wind is decreased. In the present two-level primitive equation model the jet moves poleward with decreasing surface friction and with increasing subgrid-scale diffusion. The barotropic component of the jet shows much greater sensitivity than does the baroclinic component. Experiments using different values of friction for the eddies and for the zonal means reveal that the jet latitude is primarily controlled by the drag on the zonal means. The shift in the latitude of the jet is derived from the altered equilibrium response of the zonal wind to forcing by eddies when the friction is changed and the change in meridional structure of the eddy momentum fluxes in response to the modified zonal wind. The latter effect is also displayed by linear baroclinic modes. DA - 1997/// PY - 1997/// DO - 10.1175/1520-0442(1997)010<0176:DDOTJL>2.0.CO;2 VL - 10 IS - 2 SP - 176-182 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:A1997WJ83500002&KeyUID=WOS:A1997WJ83500002 ER - TY - JOUR TI - Reply to Comment by Desmet and Govers AU - Mitasova, H. AU - Hofierka, J. AU - Zlocha, M. AU - Iverson, L. T2 - International Journal of Geographical Information Science AB - (1997). Reply to Comment by Desmet and Govers. International Journal of Geographical Information Science: Vol. 11, No. 6, pp. 611-618. DA - 1997/// PY - 1997/// DO - 10.1080/136588197242220 VL - 11 IS - 6 SP - 611-618 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0001704143&partnerID=MN8TOARS ER - TY - CONF TI - Seasonal trends in C2-C5 NHMC and isoprene measured at eight rural sites in the southeastern United States AU - Das, Mita AU - Aneja, Viney P. C2 - 1997/// C3 - Proceedings of the Air & Waste Management Association's Annual Meeting & Exhibition DA - 1997/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0031370789&partnerID=MN8TOARS ER - TY - CONF TI - Contribution of biogenic nitric oxide in urban ozone: Raleigh, NC, as a case study AU - Aneja, Viney P. AU - Roelle, Paul AU - Robarge, Wayne P. C2 - 1997/// C3 - Proceedings of the Air & Waste Management Association's Annual Meeting & Exhibition DA - 1997/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0031349526&partnerID=MN8TOARS ER - TY - CONF TI - Cooperative efforts between Veterinary Diagnostic Facility and Government Agencies in assessing two sea turtle stranding episodes AU - Stamper, M.A. AU - Epperly, S. AU - Cornish, T. AU - Lewbart, G. AU - Braun, J. AU - Boettcher, R. AU - Levine, J.F. AU - Correa, M. AU - Miller, R. AU - Colber, A. T2 - Sea Turtle Symposium C2 - 1997/3// CY - Orlando, FL DA - 1997/3// PY - 1997/3// ER - TY - CONF TI - Toxoplasma and Trichinella in Hunter-Killed Black Bears (Ursus Americanus) from Eastern North Carolina AU - Nutter, F AU - Levine, J. AU - Stoskopf, M T2 - College of Veterinary Medicine Research Forum C2 - 1997/4// CY - Raleigh, NC DA - 1997/4// PY - 1997/4// ER - TY - JOUR TI - A study of time-dependent primary productivity in a natural upper-ocean mixed layer using a biophysical model AU - Kamykowski, D. AU - Janowitz, G.S. AU - Kirkpatrick, G.J. AU - Reed, R.E. T2 - Oceanographic Literature Review DA - 1997/// PY - 1997/// VL - 44 IS - 3 SP - 231 ER - TY - CONF TI - Short-period photophysiological responses of Thalassiosira AU - Reed, Robert E. AU - Kirkpatrick, Gary J. AU - Kamykowski, Dan T2 - Ocean Optics XIII A2 - Ackleson, Steven G. A2 - Frouin, Robert J. AB - A two-day deployment of the self-contained underwater photosynthetic apparatus (SUPS) was conducted to examine the effects of high and variable natural irradiance on the optical properties and primary productivity of the diatom Thalassiosira pseudonana. Study objectives included the determination of short time response in the cycling of diadinoxanthin (DD) and diatoxanthin (DT), and associated changes in the rates of primary production, and quantum yield, and in cell absorption characteristics over a tow day period. A nutrient replete, lowlight acclimated diatom culture was placed in SUPA and in a collocated culture reservoir fitted with a quartz top. The instrument was deployed in shallow water in Sarasota Bay under fluctuating, high irradiance typical for June. A pigment sampling series reveals a correlation of DD to DT cycling with exposure to high irradiance. Net quantum yields, determined by cell absorption spectra and minute-to-minute SUPA net primary productivity values, exhibit high values initially which decay to lower values upon exposure to high light. Short time scale changes in quantum yield are observed due to changes in DD/DT cycling and fluctuating irradiance. C2 - 1997/2/6/ C3 - Ocean Optics XIII DA - 1997/2/6/ DO - 10.1117/12.266494 VL - 2963 SP - 514 - 519 PB - SPIE UR - http://dx.doi.org/10.1117/12.266494 DB - Crossref ER - TY - CONF TI - Phytoplankton quantum yield measured on minute time scales in situ AU - Kirkpatrick, Gary J. AU - Kamykowski, Dan AU - Reed, Robert E. T2 - Ocean Optics XIII A2 - Ackleson, Steven G. A2 - Frouin, Robert J. AB - We measure simultaneously, on sub-minute time scales, the downwelling irradiance spectra and the vertical attenuation spectra for downwelling irradiance of a contained phytoplankton culture while the culture is exposed to the full spectrum of an in situ light treatment. This technique incorporates miniature, fiber optical spectrometers and twin self-contained, underwater photosynthesis apparatus (SUPA). One SUPA serves as the reference, with filtered culture media in the exposure chamber. The other SUPA contains the phytoplankton sample in the exposure chamber. Using the assumptions that irradiance reflectance is small in the SUPA and that upwelling vertical attenuation equals downwelling vertical attenuation in the culture, it is possible to approximate the flux absorbed by the phytoplankton by the product of downwelling irradiance and downwelling vertical attenuation. The concurrent measurements of net carbon uptake and net oxygen production in SUPA, each minute, support calculations of net quantum yield of the phytoplankton in situ. Results from a field study using the red tide organism Gymnodinium breve illustrate the ability to quantify the effects high, fluctuating irradiance exposure near the surface. C2 - 1997/2/6/ C3 - Ocean Optics XIII DA - 1997/2/6/ DO - 10.1117/12.266417 VL - 2963 SP - 868 - 873 PB - SPIE UR - http://dx.doi.org/10.1117/12.266417 DB - Crossref KW - in situ quantum yield KW - attenuation spectra KW - phytoplankton KW - fiber-optic spectrometer KW - Gymnodinium breve KW - SUPA ER - TY - JOUR TI - Role of dynamic cartography in simulations of landscape processes based on multivariate fields AU - Mitas, L. AU - Brown, W.M. AU - Mitasova, H. T2 - Computers and Geosciences DA - 1997/// PY - 1997/// VL - 23 IS - 4 SP - 437-446 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0031454739&partnerID=MN8TOARS ER - TY - CONF TI - Multi-dimensional GIS environment for simulation and analysis of landscape processes AU - Mitasova, Helena AU - Brown, William M. AU - Mitas, Lubos AU - Warren, Steven C2 - 1997/// C3 - Paper - American Society of Agricultural Engineers DA - 1997/// VL - 1 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0031388938&partnerID=MN8TOARS ER - TY - CONF TI - Green's function Monte Carlo approach to erosion modeling in complex terrain AU - Mitas, Lubos AU - Mitasova, Helena C2 - 1997/// C3 - Paper - American Society of Agricultural Engineers DA - 1997/// VL - 1 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0031343050&partnerID=MN8TOARS ER - TY - BOOK TI - Encounters with the environment: Readings in environmental issues AU - McConnell, D. A. DA - 1997/// PY - 1997/// PB - Dubuque, IA: Kendall/Hunt SN - 9780787241650 ER - TY - JOUR TI - Effect of initial fault geometry on the development of fixed-hinge, fault-propagation folds AU - Spang, JH AU - McConnell, DA T2 - JOURNAL OF STRUCTURAL GEOLOGY AB - This paper describes how a model of fixed-hinge, basement-involved, fault-propagation folds may be adapted to apply to thin-skinned thrust faults to generate footwall synclines. Fixed-hinge, fault-propagation folding assumes that the fold-axial surfaces diverge upwards, fold hinges are fixed in the rock, the fault propagated through the forelimb, thickness changes occur in the forelimb and the forelimb progressively rotates with increasing displacement on the underlying fault. The original model for fixed-hinge, fault-propagation folds was developed for the case of a planar fault in basement with a tip line that was at the interface between basement and the overlying sedimentary cover rocks. The two geometries applicable to thin-skinned thrusts are for the cases where a fixed-hinge fault-propagation fold develops above an initial bedding-parallel detachment, and an initial fault ramp of constant dip which flattens down-dip into a bedding-parallel detachment. DA - 1997/12// PY - 1997/12// DO - 10.1016/S0191-8141(97)00065-5 VL - 19 IS - 12 SP - 1537-1541 SN - 0191-8141 ER - TY - JOUR TI - Distribution of fault slip in outcrop-scale fault-related folds, Appalachian Mountains AU - McConnell, DA AU - Kattenhorn, SA AU - Benner, LM T2 - JOURNAL OF STRUCTURAL GEOLOGY AB - Current kinematic models of ramp-related folds predict a direct relationship between ramp angle and fold shape and imply specific sequences of deformation. Analyses of outcrop-scale structures in the Valley and Ridge province of the Appalachians reveal configurations that depart from model predictions. The models fail to account for the presence of footwall synclines, and are inconsistent with measured displacement distributions on some natural faults. Observations support the interpretation that faults can grow by propagation both up- and down-dip from a nucleation point. Fault propagation in either direction may result in the formation of folds primarily on the side of the fault that is displaced in the direction of fault propagation. DA - 1997/// PY - 1997/// DO - 10.1016/s0191-8141(96)00094-6 VL - 19 IS - 3-4 SP - 257-267 SN - 0191-8141 ER - TY - JOUR TI - A study of metabolism-influence orientation in the diel vertical migration of marine dinoflagellates AU - Kamykowski, D AU - Yamazaki, H T2 - LIMNOLOGY AND OCEANOGRAPHY AB - A biophysical model is used to compare the possible impacts of two different modes of cell orientation: taxis directed and metabolisminfluenced. The included submodels provide wind‐induced turbulent mixing in the Ekman layer based on wind forcing that randomly varies from day to day; a diurnal light cycle of sea‐surface photosynthetically active radiation (PAR) that is influenced by random cloud cover and that attenuates exponentially with depth; cell‐specific respiration and photosynthesis, with the latter incorporating high PAR photoinhibition, diel variability, and sun‐shade acclimation that varies from day‐to‐day; and cell motility with swimming speed that depends on gravity, temperature, and light intensity and with the two different orientation options. Taxis‐directed orientation is based on positive phototaxis during daylight and positive geotaxis at night. Metabolism‐influenced orientation uses a depth threshold to stop descent, sunrise or a cumulative respiration threshold approached at a rate based on the previous day’s PAR exposure to start ascent, a surface response or a photoinhibition threshold to stop ascent, and sunset or a cumulative photosynthesis threshold to start descent. The thresholds act as proxies for various cellular processes including nutrient uptake or metabolic synthesis that may be involved in orientation preference. Under the modeled conditions, cells using metabolism‐influenced regulation of swimming behavior exhibit more uniformly high cumulative primary production than those that do not. DA - 1997/7// PY - 1997/7// DO - 10.4319/lo.1997.42.5_part_2.1189 VL - 42 IS - 5 SP - 1189-1202 SN - 0024-3590 ER - TY - JOUR TI - The influence of mesoscale humidity and evapotranspiration fields on a model forecast of a cold-frontal squall line AU - Koch, SE AU - Aksakal, A AU - McQueen, JT T2 - MONTHLY WEATHER REVIEW AB - Satellite imagery and rain gauge data are combined to create mesoscale detail in the initial states of relative humidity (RH) and surface moisture availability (M) for a mesoscale model simulation. The most profound impact of inserting the mesoscale initial fields was the development of a strong vertical circulation transverse to an intensifying cold front that triggered an intense frontal rainband similar to a severe squall line that was observed to develop explosively. This paper explores the causative factors leading to the formation of this intense circulation and the sensitivity of the model to the mesoscale initial fields. A substantial gradient in the initialized RH and M fields occurred across the cold front in the region where the observed frontal squall line formed. In contrast to the control run, the model simulations that incorporated the mesoscale initial analysis displayed considerable daytime warming just ahead of the front. This warming was due principally to a reduction in the RH (and, hence, low-level cloud cover) east of the front, although an increase in the cross-frontal M gradient did contribute about 25% of the warming. Increased sensible heat fluxes at the expense of decreased latent heat fluxes led to a much deeper and well-mixed prefrontal boundary layer, a more erect frontal surface, and an updraft jet just ahead of the front. A density current–like flow developed in the cold air immediately behind the front only in the presence of this cross-frontal gradient in sensible heating. Much improved forecasts of the location and timing of the frontal squall line and other precipitation systems resulted from the mesoscale initial analysis. The initial RH and M fields possessed sufficient resolution and consistency with the model dynamics to have a positive influence on the forecasts for a period of at least 12 h. This study provides evidence that differential cloud cover and evapotranspiration fields can have important impacts on frontal behavior when strong synoptic dynamics are present. Future research should attempt to improve the modeling of evapotranspiration processes, develop more objective satellite-based humidity analysis techniques, and obtain in situ mesoscale data for verification of the retrieved atmospheric and soil moisture fields. DA - 1997/3// PY - 1997/3// DO - 10.1175/1520-0493(1997)125<0384:TIOMHA>2.0.CO;2 VL - 125 IS - 3 SP - 384-409 SN - 1520-0493 ER - TY - JOUR TI - Numerical modelling and computer visualization of the storm surge in and around the Croatan-Albemarle-Pamlico Estuary system produced by Hurricane Emily of August 1993 AU - Pietrafesa, L. J. AU - Xie, L. AU - Morrison, J. AU - Janowitz, G. S. AU - Pelissier, J. AU - Keeter, K. AU - Neuherz, R. A. T2 - Mausam DA - 1997/// PY - 1997/// VL - 48 IS - 4 SP - 567-578 ER - TY - JOUR TI - Retrieving aerosol optical properties from moments of the particle size distribution AU - Yue, GK AU - Lu, J AU - Mohnen, VA AU - Wang, PH AU - Saxena, VK AU - Anderson, J T2 - GEOPHYSICAL RESEARCH LETTERS AB - The randomized minimization search technique (RMST) is a powerful tool for retrieving aerosol size distribution from a set of aerosol extinction measurements. This technique is now extended to retrieve aerosol optical properties from a known moment sequence. The new usage of the RMST is demonstrated by using particle size distributions obtained from fits to in situ measurements conducted in the troposphere and stratosphere. Good agreements (with differences less than 5%) between some aerosol optical properties calculated from the moments and those calculated directly from the particle size distributions are obtained. Our results illustrate that the RMST can be applied to parameterize particle optical properties from the lower‐order moments of an aerosol size distribution. DA - 1997/3/15/ PY - 1997/3/15/ DO - 10.1029/97GL00522 VL - 24 IS - 6 SP - 651-654 SN - 0094-8276 ER - TY - JOUR TI - Pfiesteria piscicida and other Pfiesteria-like dinoflagellates: Behavior, impacts, and environmental controls AU - Burkholder, JM AU - Glasgow, HB T2 - LIMNOLOGY AND OCEANOGRAPHY AB - Toxic Pfiesteria‐ like dinoflagellates have been implicated as causative agents of major fish kills (affecting 10 3 – 10 9 fish) in estuaries and coastal waters of the mid‐Atlantic and southeastern U.S. Transformations among an array of flagellated, amoeboid, and encysted stages in the complex life cycle of the representative species, Pfiesteria piscicida, are controlled by the availability of fresh secretions, blood, or other tissues of fish prey. P. piscicida also is a voracious predator on other estuarine microorganisms. Pfiesteria‐ like dinoflagellates require an unidentified substance(s) commonly found in fresh fish excreta‐secreta to initiate toxin production. P. piscicida is lethal to fish at low cell densities (>250–300 cells ml −1 ), and at sublethal levels (∼100–250 cells m1 −1 ) it has been shown to cause ulcerative fish diseases. P. piscicida also has been linked to serious human health impacts. This dinoflagellate is eurythermal and euryhaline, with optima for toxic activity by the most lethal stage (toxic zoospores, TZs) at ≥26°C and 15 psu, respectively. Thus far it has shown no light optimum and is capable of killing fish at any time during a 24‐h cycle. In warmer waters (≥ 15°C) flagellated stages predominate while fish are dying, whereas amoebae predominate in colder conditions and when fish are dead. Nutritional stimuli influencing P. piscicida are complex; inorganic phosphate apparently can directly stimulate TZs, whereas inorganic phosphate and nitrate indirectly promote increased production of nontoxic zoospores (NTZs, maintained in the absence of live fish, as potential precursors to lethal TZs) by stimulating their algal prey. Organic phosphate (P o ) and nitrogen are taken up by P. piscicida osmotrophically, and P o is stimulatory to both TZs and NTZs. The available data point to a critical need to characterize the chronic and acute impacts of toxic Pfiesteria‐ like dinoflagellates on fish and other targeted prey in estuarine and coastal waters that are adversely affected by cultural eutrophication. DA - 1997/7// PY - 1997/7// DO - 10.4319/lo.1997.42.5_part_2.1052 VL - 42 IS - 5 SP - 1052-1075 SN - 0024-3590 ER - TY - CONF TI - The impact of meteorology on ozone in Huston AU - Eder, B. K. AU - Davis, J. M. AU - Nychka, D. C2 - 1997/// C3 - EPA/A&WMA International Symposium on Measurement of Toxic and Related Air Pollutants (1992 May 4-9: Durham, N.C.) Measurement of toxic and related air pollutants: Proceedings of the 1992 EPA/A&WMA International Symposium CN - TD881 .E6 1992 DA - 1997/// SP - 204-214 PB - Pittsburgh, Pa.: A&WMA ER - TY - CONF TI - A rotated principal component analysis of total column ozone obtained from TOMS (Version 7.0) for 1980-1992. AU - Eder, B. K. C2 - 1997/// C3 - Measurement of toxic and related air pollutants: Proceedings of the 1991 U.S. EPA/A&WMA International Symposium (VIP (Series) ; 21). CN - TD881 .E6 1991 DA - 1997/// SP - 88-91 PB - Pittsburgh, PA: Air & Waste Management Association ER - TY - JOUR TI - Latitudinal variations in benthic processes in the abyssal equatorial Pacific: control by biogenic particle flux AU - Smith, CR AU - Berelson, W AU - Demaster, DJ AU - Dobbs, FC AU - Hammond, D AU - Hoover, DJ AU - Pope, RH AU - Stephens, M T2 - DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY AB - The equatorial Pacific forms a band of high, globally significant primary production. This productivity drops off steeply with distance from equatorial upwelling, yielding large latitudinal gradients in biogenic particle flux to the abyssal seafloor. As part of the US JGOFS Program, we studied the translation of these particle-flux gradients into the benthic ecosystem from 12°S to 9°N along 135–140°W to evaluate their control of key benthic processes, and to evaluate sediment proxies of export production from overlying waters. In October–December 1992 the remineralization rates of organic carbon, calcium carbonate and biogenic opal roughly matched the rain rates of these materials into deep sediment traps, exhibiting peak values within 3° of the equator. Rates of bioturbation near the equator were about ten-fold greater than at 9°N, and appeared to exhibit substantial dependence on particulate-organic-carbon flux, tracer time scale (i.e. age-dependent mixing), and pulsed mixing from burrowing urchins. Organic-carbon degradation within sediments near the equator was dominated by a very labile component (reaction rate constant, k approximately 15 per year) that appeared to be derived from greenish phytodetritus accumulated on the seafloor. Organic-carbon degradation at the highest latitudes was controlled by a less reactive component, with a mean k of approximately 0.075 per year. Where measured, megafaunal and macrofaunal abundances were strongly correlated with annual particulate-organic carbon flux; macrofaunal abundance in particular might potentially serve as a proxy for export production in low-energy abyssal habitats. Sedimentary microbial biomass also was correlated with the rain rate of organic carbon, but less strongly than larger biota and on shorter time scales (i.e. approximately 100 days). We conclude that the vertical flux of biogenic particlues exerts tight control on the nature and rates of benthic biological and chemical processes in the abyssal equatorial Pacific, and suggest that global changes in productivity on decadal or greater time scales could yield profound changes in deep-sea benthic ecoystems. DA - 1997/// PY - 1997/// DO - 10.1016/S0967-0645(97)00022-2 VL - 44 IS - 9-10 SP - 2295-+ SN - 0967-0645 ER - TY - JOUR TI - Impacts to a coastal river and estuary from rupture of a large swine waste holding lagoon AU - Burkholder, JM AU - Mallin, MA AU - Glasgow, HB AU - Larsen, LM AU - McIver, MR AU - Shank, GC AU - Deamer-Melia, N AU - Briley, DS AU - Springer, J AU - Touchette, BW AU - Hannon, EK T2 - JOURNAL OF ENVIRONMENTAL QUALITY AB - Abstract We tracked a swine waste spill (4.13 × 10 7 L) into a small receiving river and estuary. After 2 d, a 29‐km freshwater segment that the wastes had traversed was anoxic, with ca. 4000 dead fish floating and hung in shoreline vegetation. Suspended solids, nutrients, and fecal coliforms were 10‐ to 100‐fold higher at the plume's edge (71.7 mg SS/L, 39.6 mg NH + 4 ‐N/L, and >1 × 10 6 cfu/100 mL, respectively; cfu, colony forming units, SS; suspended solids) than in unaffected reference sites. Elevated nutrients and an oxygen sag from the plume reached the main estuary after ca. 5 d. Increased phytoplankton production was contributed by noxious algae, Synechococcus aeruginosa and Phaeocystis globosa (10 8 and 10 6 cells/mL, respectively) after 7 to 14 d. The toxic dinoflagellates, Pfiesteria piscicida and a second Pfiesteria ‐like species, increased to potentially lethal densities (10 3 cells/mL) that coincided with a fish kill and ulcerative epizootic. After 14 d, water‐column fecal coliforms generally were at 10 2 to 10 3 cfu/100 mL. But where the plume had hovered for the first 5 d, surface sediments mostly yielded ≥10 4 cfu/100 mL slurry, and after 61 d densities in surficial sediments were still at 10 3 to 10 4 cfu/100 mL. Dinoflagellate and euglenoid blooms developed and moved downestuary, where they were detected after 61 d. This study documented acute impacts to surfacewaters from a concentrated swine operation, and examined some environmental policies affecting the intensive animal operation industry. DA - 1997/// PY - 1997/// DO - 10.2134/jeq1997.00472425002600060003x VL - 26 IS - 6 SP - 1451-1466 SN - 0047-2425 ER - TY - JOUR TI - Biogenic budgets of particle rain, benthic remineralization and sediment accumulation in the equatorial Pacific AU - Berelson, WM AU - Anderson, RF AU - Dymond, J AU - Demaster, D AU - Hammond, DE AU - Collier, R AU - Honjo, S AU - Leinen, M AU - Mcmanus, J AU - Pope, R AU - Smith, C AU - Stephens, M T2 - DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY AB - Budgets of organic C (Corg), CaC03 and opal have been constructed for the Palisades, NY Pacific equatorial region at 140°W between 5°N and 5°S. Measurements of the rain and benthic remineralization rate of biogenic materials have been adjusted and normalized to account for sampling biases. Sea surface temperature serves as a master variable in normalizing sediment trap and benthic remineralization data to average conditions. The rain and remineralization rates for Corg are nearly equal: 0.40±0.05 and 0.46±0.06 mmol m−2 d−1 respectively; thus only a minor fraction of this constituent is buried. Rain and dissolution rates for biogenic opal are similarly balanced (0.3±0.06 and 0.36±0.01 mmol m−2 d−1) and consistent with the value for opal burial (0.0±0.004). The CaC03 budget appears to have changed during the Holocene. The best estimates of modern CaC03 dissolution (0.58±0.03 mmol m−2 d−1) and rain rate (0.61±0.06) are consistent with230Th-normalized carbonate accumulation rates for the late Holocene (0.1 mmol m−2 d−1). However, the balance between dissolution and rain is not consistent with early Holocene carbonate accumulation (0.3 mmol m−2 d−1 ), and this imbalance suggests: 1) a recent increase in the rate of CaC03 dissolution on the sea floor, or 2) a decrease in the rain rate of carbonate particles. Modeling230Th profiles in sediments from this region define the last 3000 years as the duration of increased dissolution or decreased particle rain. 231Pa/230Th ratios in sediments indicate that particle rain rates have remained constant or possibly increased slightly through the Holocene. Two potential causes for increased dissolution were investigated; a change in deep water carbonate saturation or a change in Co,g/CaC03 rain ratios. A model describing carbonate dissolution as a function of the degree of undersaturation and the amount of organic carbon oxidation within sediments indicates that the recent increase in dissolution is more likely due to changes in bottom water chemical composition. We propose that Pacific Ocean bottom water carbonate ion concentration has decreased by 10–15 μM over the last 3000 years. DA - 1997/// PY - 1997/// DO - 10.1016/S0967-0645(97)00030-1 VL - 44 IS - 9-10 SP - 2251-2282 SN - 0967-0645 ER - TY - JOUR TI - Hydrodynamic decoupling of recruitment, habitat quality and adult abundance in the Caribbean spiny lobster: source-sink dynamics? AU - Lipcius, RN AU - Stockhausen, WT AU - Eggleston, DB AU - Marshall, LS AU - Hickey, B T2 - MARINE AND FRESHWATER RESEARCH AB - Marine species possess dispersive stages that interconnect subpopulations, which may inhabit ‘source’ and ‘sink’ habitats, where reproduction and emigration either exceed or fall short of mortality and immigration, respectively. Postlarval supply, juvenile density and adult abundance of the Caribbean spiny lobster, Panulirus argus, were measured at four widely separated sites spanning >100 km in Exuma Sound, Bahamas. Adult abundance was lowest at a site with the highest postlarval supply and little nursery habitat; hence, it was tentatively classified as a sink. Circulation in Exuma Sound is dominated by large-scale gyres which apparently concentrate and advect postlarvae toward the nominal sink. The remaining three sites, including one marine reserve, had higher adult abundances despite lower postlarval supply, and are therefore tentatively classified as sources. Postlarval supply is probably decoupled from adult abundance by physical transport. Adult abundance is likely decoupled from postlarval supply by the effects of varying habitat quality upon postlarval and juvenile survival, as indicated by non-significant differences among sites in juvenile density. It appears that some sites with suitable settlement and nursery habitat are sources of spawning stock for Panulirus argus, whereas others with poor habitat are sinks despite sufficient postlarval influx. DA - 1997/// PY - 1997/// DO - 10.1071/MF97194 VL - 48 IS - 8 SP - 807-815 SN - 1448-6059 ER - TY - JOUR TI - Use of carbamylated hemoglobin concentration to differentiate acute from chronic renal failure in dogs AU - Vaden, S. L. AU - Gookin, Jody L. AU - Trogdon, Maureen M. AU - Langston, C. E. AU - Levine, J. AU - Cowgill, L. D. T2 - American Journal of Veterinary Research DA - 1997/// PY - 1997/// VL - 58 IS - 11 SP - 1193-1196 ER - TY - JOUR TI - Plume descriptors derived from a non-Gaussian concentration model AU - Brown, MJ AU - Arya, SP AU - Snyder, WH T2 - ATMOSPHERIC ENVIRONMENT AB - Equations for point-source releases are derived from the non-Gaussian solution to the diffusion equation for (l) the first four moments of the vertical concentration distribution (centroid, variance, skew-ness, and kurtosis), (2) the magnitude and downwind location of the maximum ground-level concentration, and (3) the plume advection velocity. Equations are obtained for both ground-level and elevated sources. Where applicable, results are compared to wind-tunnel and field measurements and/or to other less generalized equations. DA - 1997/1// PY - 1997/1// DO - 10.1016/1352-2310(96)00487-6 VL - 31 IS - 2 SP - 183-189 SN - 1352-2310 KW - plume dispersion KW - vertical concentration distribution KW - maximum ground-level concentration KW - plume advection velocity ER - TY - JOUR TI - Erythema migrans-like rash illness at a camp in North Carolina - A new tick-borne disease? AU - Kirkland, KB AU - Klimko, TB AU - Meriwether, RA AU - Schriefer, M AU - Levin, M AU - Levine, J AU - MacKenzie, WR AU - Dennis, DT T2 - ARCHIVES OF INTERNAL MEDICINE DA - 1997/12/8/ PY - 1997/12/8/ DO - 10.1001/archinte.157.22.2635 VL - 157 IS - 22 SP - 2635-2641 SN - 0003-9926 ER - TY - JOUR TI - Direct estimation of stomatal resistance for meteorological applications AU - Niyogi, DS AU - Raman, S AU - Prabhu, A AU - Kumar, U AU - Joshi, SS T2 - GEOPHYSICAL RESEARCH LETTERS AB - Stomatal Resistance ( Rs ) is one of the most important parameters in the meteorological models for weather or climate analysis and hydrological scenario estimations. The information for estimating Rs is sparse particularly in the tropics limiting the development of a detailed global terrestrial biosphere‐atmosphere interaction analysis. One of the reasons for the scarcity of tropical data is the high cost of instrumentation. A hypothesis is presented to estimate Rs from plant‐nutrient status in a field study using stomatal aperture observations to develop a simple, cost‐effective technique for first‐order estimations. Comparisons with observations from a tropical field experiment are encouraging and an approach is suggested using this method for initialization of numerical models using remote sensing techniques based on nitrogen, humidity, and temperature as sufficient parameters. DA - 1997/7/15/ PY - 1997/7/15/ DO - 10.1029/97GL01790 VL - 24 IS - 14 SP - 1771-1774 SN - 0094-8276 ER - TY - JOUR TI - A validation of back trajectories of air masses by principal component analysis of ion concentrations in cloud water AU - Deininger, CK AU - Saxena, VK T2 - ATMOSPHERIC ENVIRONMENT AB - The chemical characteristics of polluted marine, polluted continental, and highly polluted air masses were studied by applying principal component analysis (PCA) to the cloud water data collected during field studies at a site located in Mt. Mitchell (2038 m msl, 35°44'05″N, 82°17'15″W) State Park, NC. The site intercepts air masses arriving from the East (polluted marine), the West (polluted continental), and the Northwest (highly polluted). The PCA was used to study the relationship between the ionic constituents of the cloud water and the type of air mass in which the cloud formed. By applying PCA to the cloud water chemistry, a set of highly intercorrelated variables (ions) was replaced with a set of uncorrelated principal components. Using PCA, we can identify the most significant acids and salts dissolved in the cloud water. For instance, sulfuric acid was found to be most influential in clouds formed in highly polluted air masses. Sea salt particles were present in the majority of the polluted marine cloud events. Calcium was found to be the most important ion in the polluted continental cloud events. The type of the air mass was determined by 48-h back trajectory analysis using Hybrid Single-Particle Lagrangian Integrated Trajectories (HYSPLIT) model. The results of the HYSPLIT model were confirmed by the PCA of the ionic composition of cloud water collected at the mountain top site. DA - 1997/1// PY - 1997/1// DO - 10.1016/1352-2310(96)00152-5 VL - 31 IS - 2 SP - 295-300 SN - 1352-2310 KW - principal component analysis KW - cloud water KW - ion concentrations KW - air masses KW - source analysis ER - TY - JOUR TI - A pervasive millennial-scale cycle in North Atlantic Holocene and glacial climates AU - Bond, G AU - Showers, W AU - Cheseby, M AU - Lotti, R AU - Almasi, P AU - deMenocal, P AU - Priore, P AU - Cullen, H AU - Hajdas, I AU - Bonani, G T2 - SCIENCE AB - Evidence from North Atlantic deep sea cores reveals that abrupt shifts punctuated what is conventionally thought to have been a relatively stable Holocene climate. During each of these episodes, cool, ice-bearing waters from north of Iceland were advected as far south as the latitude of Britain. At about the same times, the atmospheric circulation above Greenland changed abruptly. Pacings of the Holocene events and of abrupt climate shifts during the last glaciation are statistically the same; together, they make up a series of climate shifts with a cyclicity close to 1470 ± 500 years. The Holocene events, therefore, appear to be the most recent manifestation of a pervasive millennial-scale climate cycle operating independently of the glacial-interglacial climate state. Amplification of the cycle during the last glaciation may have been linked to the North Atlantic's thermohaline circulation. DA - 1997/11/14/ PY - 1997/11/14/ DO - 10.1126/science.278.5341.1257 VL - 278 IS - 5341 SP - 1257-1266 SN - 0036-8075 ER - TY - JOUR TI - Low-field trap generation dependence on the injection current density in gate insulators - How valid are accelerated hot electron measurements? AU - Kim, HS AU - Reisman, A AU - Williams, CK T2 - JOURNAL OF THE ELECTROCHEMICAL SOCIETY AB - "Continuous" low gate insulator field (1 MV/cm) electron injection in insulated gate field effect transistors using a pulsed injection technique (PIT) was conducted in the dose range 1013 to 1017 e/cm2 over the range of current densities from 1.5 × 10−7 to 3.4 × 10−5 A/cm2. PIT enables independent control of insulator fields and injection current densities, while not causing optically induced shallow trap depopulation. As is generally the case, the threshold voltage shift, ΔVD varies monotonically with dose, and can be modeled using a defect generation power law requiring fewer adjustable parameters than is necessary using a first order trapping model. It was also found that for a given dose the injection current density has a profound effect on the observed magnitude of trap generation. Previously, the total dose and insulator field were thought to be the only determining factors in trap generation. Based on these results, it appears that when the intrinsic defect concentration(s) is to be determined, a very low current density (injection rate) should be used to minimize trap generation effects which would confuse the issue. It is reported also for the first time that the expected in‐use lifetime of the devices, calculated from the injection data, also exhibits a power law dependency on the injection current density. These results raise serious questions about the validity of aggressive injection techniques (such as avalanche injection and Fowler‐Nordheim approaches), of the existence of ultrasmall cross section electron traps based on such methods, and of aggressive accelerated aging conclusions, based on the extrapolation of high injection current density data to end‐of‐life threshold voltage shifts. DA - 1997/7// PY - 1997/7// DO - 10.1149/1.1837847 VL - 144 IS - 7 SP - 2517-2521 SN - 0013-4651 ER - TY - JOUR TI - Effect of three different boundary-layer parameterisations in a regional atmospheric model on the simulation of summer monsoon circulation AU - Potty, KVJ AU - Mohanty, UC AU - Raman, S T2 - BOUNDARY-LAYER METEOROLOGY DA - 1997/9// PY - 1997/9// DO - 10.1023/A:1000402013655 VL - 84 IS - 3 SP - 363-381 SN - 1573-1472 KW - Indian summer monsoon circulation KW - monsoon depression KW - planetary boundary layer KW - bulk method KW - first order closure scheme KW - TKE closure scheme ER - TY - JOUR TI - Biological-geological interactions: Storm effects on macroalgal communities mediated by sediment characteristics and distribution AU - Renaud, PE AU - Riggs, , SR AU - Ambrose, WG AU - Schmid, K AU - Snyder, SW T2 - CONTINENTAL SHELF RESEARCH AB - The North Carolina mid-continental shelf is characterized by a complex sequence of rock suostrates, or hardbottoms, which support rich communities of invertebrates and benthic macroalgae. Three hardbottom sites in southern Onslow Bay have been studied over 3 years, including studies of sedimentology and dynamics of the surficial sand bodies and the benthic community structure. Between 1991 and 1993 at two of the sites, there were large differences in sediment characteristics and depth at several of the zones sampled. These differences coincided with considerable variability in the abundance and species composition of the macroalgal community. In sampling zones where there was consistently low sediment coverage, algal biomass was uniformly high. There was only sparse, if any, macroalgal growth where gravelly sand or fine sand covered the hard substrate. Based on hindcasting of bottom currents generated by the March 1993 ‘storm of the century’, it appears that this episodic event cleared fine sand from upper flat hardbottoms, resulting in considerable colonization and growth of macroalgae between the summers of 1992 and 1993. Macroalgae continued to be excluded from areas of gravelly sand, even after storm passage. Furthermore, the storm did not have any significant effects on scarps and ramp areas where sediment cover was already low. Therefore, distribution and characteristics of sediments influenced where the storm was to have biological consequences. Based on the wide areal extent of the upper flat hardbottoms in Onslow Bay, the newly formed macroalgal meadows represent a significant increase in benthic biomass and habitat complexity on a regional scale with potentially important ecological consequences. DA - 1997/1// PY - 1997/1// DO - 10.1016/0278-4343(96)00019-2 VL - 17 IS - 1 SP - 37-56 SN - 0278-4343 ER - TY - JOUR TI - Trophic controls on stage transformations of a toxic ambush-predator dinoflagellate AU - Burkholder, JM AU - Glasgow, HB T2 - JOURNAL OF EUKARYOTIC MICROBIOLOGY AB - The toxic dinoflagellate, Pfiesteria piscicida, was recently implicated as the causative agent for about 50% of the major fish kills occurring over a three-year period in the Albemarle-Pamlico Estuarine System of the southeastern USA. Transformations between life-history stages of this dinoflagellate are controlled by the availability of fresh fish secretions or fish tissues, and secondarily influenced by the availability of alternate prey including bacteria, algae, microtauna, and mammalian tissues. Toxic zoospores of P. piscicida subdue fish by excreting lethal neurotoxins that narcotize the prey, disrupt its osmoregulatory system, and attack its nervous system. While prey are dying, the zoospores feed upon bits of fish tissue and complete the sexual phase of the dinoflagellate life cycle. Other stages in the complex life cycle of P. piscicida include cryptic forms of filose, rhizopodial, and lobose amoebae that can form within minutes from toxic zoospores, gametes, or planozygotes. These cryptic amoebae feed upon fish carcasses and other prey and, thus far, have proven less vulnerable to microbial predators than flagellated life-history stages. Lobose amoebae that develop from toxic zoospores and planozygotes during colder periods have also shown ambush behavior toward live fish. In the presence of abundant flagellated algal prey, amoeboid stages produce nontoxic zoospores that can become toxic and form gametes when they detect what is presumed to be a threshold level of a stimulatory substance(s) derived from live fish. The diverse amoeboid stages of this fish "ambush-predator" and at least one other Pfiesteria-like species are ubiquitous and abundant in brackish waters along the western Atlantic and Gulf Coasts, indicating a need to re-evaluate the role of dinoflagellates in the microbial food webs of turbid nutrient-enriched estuaries. DA - 1997/// PY - 1997/// DO - 10.1111/j.1550-7408.1997.tb05700.x VL - 44 IS - 3 SP - 200-205 SN - 1066-5234 KW - amoebae KW - estuary KW - fish kill KW - microbial prey KW - Pfiesteria KW - toxic dinoflagellates ER - TY - JOUR TI - Trends and analysis of ambient NO, NOy, CO, and ozone concentrations in Raleigh, North Carolina AU - Aneja, VP AU - Kim, DS AU - Chameides, WL T2 - CHEMOSPHERE AB - Ambient concentrations of NO and NOy as well as O3 and CO were measured during August 19 to September 1, 1991 in downtown Raleigh, North Carolina as a part of the Southern Oxidants Study-Southern Oxidants Research Program on Ozone Non-Attainment (SOS-SORP/ONA). These measurements were made in an effort to provide insight into the characteristics of nitrogen oxides and their role in the formation of ozone in the urban Southeast U.S. environment. NO and NOy showed bimodal diumal variations with peaks in the morning (06:00 – 08:00 EST) and in the late evening (21:00 – 23:00 EST). These peaks at this urban site correspond to the coupled effects of rush hour traffic and meteorological conditions (i.e., variation of mixing height and dispersion conditions). The overall average NO and NOy concentrations were found to be 6.1 ± 5.4 ppbv (range: 0 to 70 ppbv) and 14.9 ± 8.1 ppbv (range: 0.3 to 110 ppbv), respectively. Average daily maxima of NO and NOy (18.3 ppbv and 27.4 ppbv) occurred during the morning. O3 showed a diumal variation with a maximum in the afternoon between 14:00 and 16:00 EST; and a mean concentration 20 ± 10 ppbv (range: 1 to 62 ppbv). Maximum O3 and CO concentrations during weekdays result from NO and CO emitted from mobile sources during the morning rush hour. Background CO concentration at Raleigh was estimated to be ∼ 470 ± 52 ppbv. A linear correlation of r2 = 0.53 between CO and NOy was observed. The ratio of CO to NOy (∼ 16) at the Raleigh site suggests that mobile sources are the major contributor to NO and NOy concentrations at the site. DA - 1997/2// PY - 1997/2// DO - 10.1016/S0045-6535(96)00393-1 VL - 34 IS - 3 SP - 611-623 SN - 0045-6535 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0031081452&partnerID=MN8TOARS ER - TY - JOUR TI - The role of orography in determining the Sahelian climate AU - Semazzi, FHM AU - Sun, LQ T2 - INTERNATIONAL JOURNAL OF CLIMATOLOGY AB - We have examined numerical modelling evidence based on the NASA GEOS-1 general circulation model in order to investigate the role of orography in determining the West African summer climate anomalies. Orographic climatic control and the influence of sea-surface temperature (SST) anomaly forcing were investigated by systematic suppression or inclusion of these effects in the numerical experiments. Our main finding is that the orography of Africa plays a major role in determining the climate of the Sahel and the coastal region of West Africa during the northern hemispheric summer season. These orographic effects are comprised of: (i) a quasi-stationary orographic ridge–trough dipole generated by the passage of the low-level prevailing easterlies over the Atlas–Ahaggar mountain complex over northern Africa, and (ii) an elongated zonal windward orographic ridge generated as the cross-equatorial summer monsoons from the South Atlantic Ocean basin ascends over the elevated landmass of West Africa. Over the Sahel, the moist south-westerly flow emanating from the Atlas–Ahaggar orographic trough over the Atlantic Ocean and the dry hot north-easterlies originating from the corresponding orographic windward ridge tend to converge along a zonal axis thus reinforcing the Inter-Tropical Convergence Zone. This results in wetter conditions over the Sahel than would have been the case in the absence of orography. The model simulations show that further to the south along the coastal region of West Africa, the zonal orographic ridge results in drier conditions than in the model runs when orography is suppressed. The net result is a permanent orographic-induced rainfall dipole pattern over West Africa. Further model simulations were conducted in which the 1973 SST anomaly conditions were described with or without the orography of Africa. The 1973 SST anomaly pattern is characterized by positive anomalies in the Southern Hemisphere and negative anomalies in the Northern Hemisphere. The model results show a weaker orographic-induced rainfall dipole pattern across West Africa in response to the 1973 SST anomaly pattern. The net result is wetter conditions along the coastal region and rainfall deficits over the Sahelian zonal strip. © 1997 by the Royal Meteorological Society. DA - 1997/5// PY - 1997/5// DO - 10.1002/(SICI)1097-0088(199705)17:6<581::AID-JOC134>3.0.CO;2-E VL - 17 IS - 6 SP - 581-596 SN - 0899-8418 KW - Sahel KW - orography KW - summer climate anomalies KW - NASA GEOS-1 GCM ER - TY - JOUR TI - Nowcasting convective activity for space shuttle landings during easterly flow regimes AU - Bauman, W. H. AU - Kaplan, M. L. AU - Businger, S. T2 - Weather and Forecasting AB - Space shuttle landings at the shuttle landing facility at Kennedy Space Center are subject to strict weather-related launch commit criteria and flight rules. Complex launch commit criteria and end-of-mission flight rules demand very accurate nowcasts (forecasts of less than 2 h) of cloud, wind, visibility, precipitation, turbulence, and thunderstorms prior to shuttle launches and landings. During easterly flow regimes the onset of convective activity has proven to be particularly difficult to predict. Contrasting weather ranging from clear skies to thunderstorms occurs on days with seemingly similar synoptic environments. Four days of easterly flow during the Convection and Precipitation/Electrification (CaPE) Experiment were investigated in an effort to identify and simulate key features that distinguish convectively active and suppressed conditions. Data from CaPE and operational data, including satellite imagery and National Centers for Environmental Prediction model analysis output over the Florida peninsula and surrounding data-sparse Atlantic Ocean, are combined in the research. It is found that elevated moisture in the midtroposphere above the marine boundary layer helps distinguish convectively active and passive days. Moreover, analysis reveals that the moisture distribution is related to jet dynamics in the upper troposphere. A series of simulations using the Mesoscale Atmospheric Simulation System (MASS) model was undertaken. The MASS model run with a coarse grid (45 km) correctly simulates the development of the upper-level jet streak and its general impact on convective activity over the Florida peninsula. The MASS model run with a nested (11 km) grid and moisture enhancement of the initial model state from radar, satellite, and surface data results in the best short-term (6 h) forecast of relative humidity and precipitation patterns over the Florida peninsula and proximate coastal environment. Implications of the research results for nowcasting convective activity over Cape Canaveral are discussed. DA - 1997/// PY - 1997/// DO - 10.1175/1520-0434(1997)012<0078:NCAFSS>2.0.CO;2 VL - 12 IS - 1 SP - 78-107 ER - TY - JOUR TI - Mesoanalysis of summertime convergence zones in central and eastern North Carolina AU - Koch, SE AU - Ray, CA T2 - WEATHER AND FORECASTING AB - It is demonstrated that it is possible to perform informative mesoanalysis of summertime convergence boundaries in the southeastern United States by combining capabilities of the new WSR-88D Doppler radar with Geostationary Operational Environmental Satellite imagery and conventional surface data. Observed phenomena are identified as thunderstorm outflow boundaries, sea-breeze fronts, horizontal convective rolls, deep synoptic-scale fronts, prefrontal troughs, shallow fronts (airmass boundaries lacking upper-level support), stationary and propagating boundaries of unknown origin, and the “Piedmont trough,” which is apparently a new feature discovered in the course of this research. The transition zone between the Piedmont and the Coastal Plain was found to be a preferred location for convergence boundaries. An unexpectedly far inland advance of the sea breeze to central North Carolina occurred in some instances. The very sensitive “clear air mode” of the WSR-88D radar, when used in combination with high-resolution visible satellite imagery and surface mesoanalysis, made it possible to see that so-called random thunderstorm activity is either directly initiated or strongly controlled by such convergence features. Many of these features would be too weak to detect using conventional radar. The ability to perform such mesoanalyses with operational data hinges on using all of the observing tools available, since some boundaries are either ambiguous or imperceptible in visible satellite imagery, most are nearly impossible to find in conventional surface data alone, and radar suffers from well-known sampling problems at large range. The role of radar-detected interactions between convergence boundaries in initiating convection was found to be significantly different than what has been reported in Colorado by Wilson and Schreiber. Fronts in North Carolina produced convective cells of at least 40 dBZ in every instance without the need to interact with other boundaries, whereas troughs and outflow boundaries did so 86% and 70% of the time, respectively. Boundary interactions also occur significantly more often than in Colorado, and those interactions tend to result in deep convection more frequently irrespective of their motion. These results indicate that thunderstorm nowcasting may be possible in North Carolina and surrounding regions. DA - 1997/3// PY - 1997/3// DO - 10.1175/1520-0434(1997)012<0056:MOSCZI>2.0.CO;2 VL - 12 IS - 1 SP - 56-77 SN - 0882-8156 ER - TY - JOUR TI - Interaction between Hurricane Florence (1988) and an upper-tropospheric westerly trough AU - Shi, JJ AU - Chang, S AU - Raman, S T2 - JOURNAL OF THE ATMOSPHERIC SCIENCES AB - The Naval Research Laboratory’s limited-area numerical prediction system, a version of Navy Operational Regional Atmospheric Prediction System, was used to investigate the interaction between Hurricane Florence (1988) and its upper-tropospheric environment. The model was initialized with the National Meteorological Center (now the National Centers for Environmental Prediction)/Regional Analysis and Forecasting Systems 2.5° analysis at 0000 UTC 9 September 1988, enhanced by a set of Omega dropwindsonde data through a three-pass nested-grid objective analysis. Diagnosis of the 200-mb level structure of the 12-h forecast valid for 1200 UTC 9 September 1988 showed that the outflow layer was highly asymmetric with an outflow jet originating at approximately 3° north of the storm. In agreement with the result of an idealized simulation (), there was a thermally direct, circum-jet secondary circulation in the jet entrance region and a thermally indirect one in a reversed direction in the jet exit region. In several previous studies, it was postulated that an approaching westerly jet had modulated the convection and intensity variations of Florence. In a variational numerical experiment in this study, the approaching westerly jet was flattened out by repeatedly setting the jet-level meridional wind component and zonal temperature perturbations to zero in the normal mode initialization procedure. Compared with the control experiment, the variational experiment showed that the sudden burst of Florence’s inner core convection was highly correlated with the approaching upper-tropospheric westerly jet. These experiments also suggested that the approaching upper-tropospheric westerly jet was crucial to the intensification of Florence’s inner core convection between 1000 and 1500 UTC 9 September, which occurred prior to the deepening of the minimum sea level pressure (from 997 to 987 mb) between 1200 UTC 9 September and 0000 UTC 10 September. Many earlier studies have attempted an explanation for the effect on tropical cyclones of upper-tropospheric forcings from the eddy angular momentum approach. The result of this study provides an alternative but complementary mechanism of the interaction between an upper-level westerly trough and a tropical cyclone. DA - 1997/5/1/ PY - 1997/5/1/ DO - 10.1175/1520-0469(1997)054<1231:IBHFAA>2.0.CO;2 VL - 54 IS - 9 SP - 1231-1247 SN - 0022-4928 ER - TY - JOUR TI - Chemical and mutagenic analysis of volatile organic compounds in Raleigh air samples at three different elevations before, during, and after Hurricane Gordon AU - dePollok, FS AU - Aneja, VP AU - Hughes, TJ AU - Claxton, LD T2 - CHEMOSPHERE AB - Volatile organic compounds (VOCs) were collected and measured at a television tower 10 km southeast of downtown Raleigh, North Carolina at three different levels (Surface, < 1 m; Mid, 240 m; and Top, 433 m) during the summer and fall of 1994. The combined presence of ozone, arenes, and nitrogen oxides (NOx) suggested possible nitration of arenes during atmospheric mixing. Air samples, therefore, were collected using XAD-filled canisters at each level on the tower prior to, during, and after Hurricane Gordon. Collected air samples were Soxhlet extracted and analyzed with the Salmonella typhimurium microsuspension mutagenicity assay using strains YG1021 and YG1026 which are sensitive to nitrarenes. Significant mutagenicity was observed only in the Top and Mid level samples for the post-hurricane, normal weather air samples. Surface samples were not mutagenic, which suggests the long-range transport of these mutagenic nitrarenes. DA - 1997/8// PY - 1997/8// DO - 10.1016/S0045-6535(97)00130-6 VL - 35 IS - 4 SP - 879-893 SN - 0045-6535 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0343907818&partnerID=MN8TOARS KW - Salmonella KW - mutagenicity KW - volatile organic compounds KW - ambient air monitoring KW - meteorology KW - Hurricane ER - TY - JOUR TI - A view into the subsurface of Mauna Kea volcano, Hawaii: Crystallization processes interpreted through the petrology and petrography of gabbroic and ultramafic xenoliths AU - Fodor, RV AU - Galar, P T2 - JOURNAL OF PETROLOGY DA - 1997/5// PY - 1997/5// DO - 10.1093/petrology/38.5.581 VL - 38 IS - 5 SP - 581-624 SN - 0022-3530 KW - gabbroic xenoliths KW - ultramafic xenoliths KW - cumulate KW - Hawaii petrology KW - in situ crystallization KW - gravity settling KW - Mauna Kea volcano ER - TY - JOUR TI - A numerical model of the transport and diffusion of Peronospora tabacina spores in the evolving atmospheric boundary layer AU - Yao, CG AU - Arya, SP AU - Davis, J AU - Main, CE T2 - ATMOSPHERIC ENVIRONMENT AB - Abstract Numerical solutions of the diffusion equation of Peronospora tabacina spores from a finite-area source over flat terrain in the evolving convective boundary layer are presented. Temporal variations in the release of spores, atmospheric stability, wind speed, and eddy diffusivity are considered. The model also includes the vertical variations of wind and eddy diffusivity. The model results indicate that ground level concentrations decrease with time as wind speed and eddy diffusivity increase in the evolving convective boundary layer. The loss of P. tabacina spores due to deposition at the surface also decrease with increasing instability and wind speed. Deposition is found to be particularly important close to the source area. DA - 1997/6// PY - 1997/6// DO - 10.1016/S1352-2310(96)00181-1 VL - 31 IS - 11 SP - 1709-1714 SN - 1352-2310 KW - dispersion model KW - P-tabacina spore KW - transport KW - diffusion KW - concentration KW - deposition KW - convective boundary layer ER - TY - JOUR TI - A flow visualization study of spore release using a wind tunnel-mounted laser light sheet AU - Davis, JM AU - Eisner, AD AU - Wiener, RW AU - Main, CE T2 - PLANT DISEASE AB - A phase Doppler anemometry system in combination with a laser light sheet was used in a low-speed recirculating wind tunnel to examine the flow field around an individual leaf. Turbulence similar to that encountered near the surface of the earth in a neutral stability boundary layer was generated using a grid at the upwind end of the wind tunnel test section. Individual healthy and diseased plant leaves were introduced into the tunnel with the leaf tip pointing downwind. The Mie-scattered radiation from the spores departing the diseased leaf was captured on videotape. Image processing software was used to enhance the visual quality of the individual frames from the videotape and to make spore velocity calculations. Three main vortex regions around the leaf were identified. The importance of these regions to the separation of the spores from the leaf surface and their subsequent downwind movement was analyzed. DA - 1997/9// PY - 1997/9// DO - 10.1094/PDIS.1997.81.9.1057 VL - 81 IS - 9 SP - 1057-1065 SN - 0191-2917 KW - coherent structures KW - sporangiospores ER - TY - JOUR TI - Thrombocytosis in 24 Horses (1989-1994) AU - Sellon, Debra C. AU - Levine, Jay F. AU - Palmer, Kate AU - Millikin, Everett AU - Grindem, Carol AU - Covington, Patrice T2 - Journal of Veterinary Internal Medicine AB - The records of horses presented to the Veterinary Teaching Hospital of North Carolina State University College of Veterinary Medicine between January 1, 1989 and April 30, 1994 were evaluated to determine risk factors associated with thrombocytosis. Of the 2,346 horses for which a CBC was performed, 24 (1.0%) had a platelet count > 400,000/microL. Demographic, diagnostic, physical examination, and clinicopathologic variables from these cases were compared with a reference population consisting of 189 horses with a normal platelet count presenting during the same period. Infectious/ inflammatory disorders were observed more commonly in horses with high platelet counts than in horses with normal platelet counts. Initial independent evaluation of demographic variables revealed that horses more than 3 years of age, females, and geldings were less likely to have thrombocytosis than were younger horses or stallions. Independent analysis of clinicopathologic variables revealed that horses with thrombocytosis were more likely to have hyperfibrinogenemia, leukocytosis, hypoproteinemia, and anemia than were horses with normal platelet counts. Physical examination parameters associated with thrombocytosis included tachycardia and pyrexia. In the final multivariable model, the variables with the strongest association with thrombocytosis included leukocytosis, anemia, and hyperfibrinogenemia. Thrombocytosis rarely causes clinical problems in horses and is not likely to require specific antiplatelet therapy. The strong association of thrombocytosis with infectious/inflammatory disorders, however, should lead clinicians to suspect these types of conditions in horses with high platelet counts. DA - 1997/1// PY - 1997/1// DO - 10.1111/j.1939-1676.1997.tb00069.x VL - 11 IS - 1 SP - 24-29 LA - en OP - SN - 0891-6640 1939-1676 UR - http://dx.doi.org/10.1111/j.1939-1676.1997.tb00069.x DB - Crossref ER - TY - JOUR TI - Severe thunderstorm and tornado warnings at Raleigh, North Carolina AU - Hoium, DK AU - Riordan, AJ AU - Monahan, J AU - Keeter, KK T2 - BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY AB - The National Weather Service issues public warnings for severe thunderstorms and tornadoes when these storms appear imminent. A study of the warning process was conducted at the National Weather Service Forecast Office at Raleigh, North Carolina, from 1994 through 1996. The purpose of the study was to examine the decision process by documenting the types of information leading to decisions to warn or not to warn and by describing the sequence and timing of events in the development of warnings. It was found that the evolution of warnings followed a logical sequence beginning with storm monitoring and proceeding with increasingly focused activity. For simplicity, information input to the process was categorized as one of three types: ground truth, radar reflectivity, or radar velocity. Reflectivity, velocity, and ground truth were all equally likely to initiate the investigation process. This investigation took an average of 7 min, after which either a decision was made not to warn or new information triggered the warning. Decisions not to issue warnings were based more on ground truth and reflectivity than radar velocity products. Warnings with investigations of more than 2 min were more likely to be triggered by radar reflectivity, than by velocity or ground truth. Warnings with a shorter investigation time, defined here as “immediate trigger warnings,” were less frequently based on velocity products and more on ground truth information. Once the decision was made to warn, it took an average of 2.1 min to prepare the warning text. In 85% of cases when warnings were issued, at least one contact was made to emergency management officials or storm spotters in the warned county. Reports of severe weather were usually received soon after the warning was transmitted—almost half of these within 30 min after issue. A total of 68% were received during the severe weather episode, but some of these storm reports later proved false according to Storm Data. Even though the WSR-88D is a sophisticated tool, ground truth information was found to be a vital part of the warning process. However, the data did not indicate that population density was statistically correlated either with the number of warnings issued or the verification rate. DA - 1997/11// PY - 1997/11// DO - 10.1175/1520-0477(1997)078<2559:STATWA>2.0.CO;2 VL - 78 IS - 11 SP - 2559-2575 SN - 0003-0007 ER - TY - JOUR TI - Petrology, mineralogy and geochemistry of the Rolesville Granitic Batholith, Eastern Piedmont, North Carolina AU - Kosecki, J. AU - Fodor, R. V. T2 - Southeastern Geology DA - 1997/// PY - 1997/// VL - 37 IS - 2 SP - 91- ER - TY - JOUR TI - Operational forecasting and detection of mesoscale gravity waves AU - Koch, SE AU - OHandley, C T2 - WEATHER AND FORECASTING AB - Mesoscale gravity waves display periods of 1–4 h, have wavelengths of 50–500 km, and can have important effects upon the sensible weather. Real-time prediction, detection, and nowcasting of these mesoscale phenomena is shown to be feasible, due to recent major advances in operational observing and modeling systems. The ability to predict the likelihood of a gravity wave event rests upon recognizing the synoptic flow pattern in which such waves are consistently found to occur. The delineation of the most likely region for wave activity can be further refined by computing simple indicators of unbalanced flow and conducting a cursory search for a suitable wave “duct” with meso-Eta Model data. Particular emphasis should be placed on propagating unbalanced fields. Whenever and wherever a suitable gravity wave environment is found, the Automated Surface Observing System pressure data should be carefully monitored for evidence of gravity wave activity. An automated gravity wave detection system is developed. It is shown that application of a time-to-space conversion adaptation of the Barnes objective analysis scheme to bandpass-filtered 5-min surface observations enables the detection of gravity waves with scales as small as 150 km and their separation from smaller-scale convective phenomena. This scheme requires accurate knowledge of the wave propagation velocity. A method is presented and successfully tested for this purpose, which is based on an adaptation of wave-ducting theory to the mesoscale model forecast fields. The proposed procedure is demonstrated with a gravity wave event that occurred during STORM-FEST. A solitary wave of depression formed as an upper-level jet streak approached an inflection axis in the diffluent height field downstream of the Rocky Mountains. This wave generation region was diagnosed from mesoscale model forecasts as being unbalanced. A wave duct was diagnosed north of a warm front in both the model forecasts and the STORM-FEST soundings over the region traversed by the observed waves. The analyzed pressure and wind perturbation fields successfully portray the evolution of the gravity wave into a wave train as strong thunderstorms developed with the wave. The mesoscale model produced a gravity wave similar in most respects to that analyzed prior to the development of convection. These results suggest that mesoscale gravity waves can be predicted and analyzed with operationally available data and numerical model guidance. DA - 1997/6// PY - 1997/6// DO - 10.1175/1520-0434(1997)012<0253:OFADOM>2.0.CO;2 VL - 12 IS - 2 SP - 253-281 SN - 0882-8156 ER - TY - JOUR TI - Observations of the Ekman balance at 8 degrees 30' N in the Arabian Sea during the 1995 southwest monsoon AU - Chereskin, TK AU - Wilson, WD AU - Bryden, HL AU - Ffield, A AU - Morrison, J T2 - GEOPHYSICAL RESEARCH LETTERS AB - The Ekman transport is estimated from two sets of hydrographic and shipboard acoustic Doppler current profiler (ADCP) velocity observations made during June and September 1995, during the southwest monsoon in the Arabian Sea. Both sets of measurements were made along latitude 8°30′ N, designated as World Ocean Circulation Experiment (WOCE) line I1W, from Somalia to Sri Lanka. The Ekman transport estimates calculated from ageostrophic velocity were southward: 17.6 ± 2.4 10 6 m³ s −1 in June and 7.9 ± 2.7 10 6 m³ s −1 in September. These direct estimates were in good agreement with those predicted by the Ekman balance using both shipboard and climatological winds. The vertical structure of the ageostrophic velocity and the stratification were quite different between the two occupations of the transect. The wind‐driven momentum was confined to a very shallow layer in June (about 50 m) and the surface layer was strongly stratified, with a maximum salinity layer at depths between 50 and 70 m. The ageostrophic velocity penetrated much deeper in September (to about 160 m) and the pycnocline was correspondingly deeper. In both cases, the Ekman transport penetrated beneath the mixed layer, to the top of the pycnocline. DA - 1997/11/1/ PY - 1997/11/1/ DO - 10.1029/97GL01057 VL - 24 IS - 21 SP - 2541-2544 SN - 0094-8276 ER - TY - JOUR TI - Numerical simulations of a gravity wave event over CCOPE .1. The role of geostrophic adjustment in mesoscale jetlet formation AU - Kaplan, ML AU - Koch, SE AU - Lin, YL AU - Weglarz, RP AU - Rozumalski, RA T2 - MONTHLY WEATHER REVIEW AB - Mesoscale model simulations are performed in order to provide insight into the complex role of jet streak adjustments in establishing an environment favorable to the generation of gravity waves on 11–12 July 1981. This wave event was observed in unprecedented detail downstream of the Rocky Mountains in Montana during the Cooperative Convective Precipitation Experiment. The high-resolution model simulations employ a variety of terrain treatments in the absence of the complicating effects of precipitation physics in order to examine the complex interactions between orography and adiabatic geostrophic adjustment processes. Results indicate that prior to gravity wave formation, a four-stage geostrophic adjustment process modified the structure of the mid- to upper-tropospheric jet streak by creating secondary mesoscale jet streaks (jetlets) to the southeast of the polar jet streak in proximity to the gravity wave generation region (WGR). During stage I, a strong rightward-directed ageostrophic flow in the right exit region of the polar jet streak (J1) developed over west-central Montana. This thermally indirect transverse secondary circulation resulted from inertial-advective adjustments wherein momentum was transported downstream and to the right of J1 as air parcels decelerated through the exit region. During stage II, a highly unbalanced jetlet (J2) formed just northwest of the WGR in response to the inertial-advective forcing accompanying the ageostrophic circulation associated with J1. The mass field adjusted to this ageostrophic wind field. An adiabatic cooling and warming dipole resulting from this thermally indirect secondary circulation was the cause for frontogenesis and a rightward shift in the midtropospheric pressure gradients. Since this secondary circulation associated with J2 occurred above a dramatic vertical variation in the thermal wind, the vertical transport of potentially colder air from below was larger ahead of and to the right of J1, thus shifting the new jetlet (J2) well away from J1 as the mass field adjusted to the new wind field. Stage III was established when the new mass field, which developed in association with J2 during stage II, set up a dynamically unbalanced circulation oriented primarily across the stream, and directly over the WGR. This new leftward-directed ageostrophic cross-stream flow (A) formed between jetlet J2 and the original exit region of the polar jet streak J1. Finally, a midlevel mesoscale jetlet (J3) is simulated to have developed in stage IV over the WGR in response to the integrated mass flux divergence associated with both the stage II and III adjustment processes. This lower-level return branch circulation to jetlet J2 was further enhanced by velocity divergence accompanying the localized cross-stream ageostrophic wind maximum (A), which develops during stage III. The entire multistage geostrophic adjustment process required about 12 h to complete over a region encompassing approximately 400 km × 400 km. DA - 1997/6// PY - 1997/6// DO - 10.1175/1520-0493(1997)125<1185:NSOAGW>2.0.CO;2 VL - 125 IS - 6 SP - 1185-1211 SN - 1520-0493 ER - TY - JOUR TI - Magma-reservoir crystallization processes: small-scale dikes in cumulate gabbros, Mauna Kea Volcano, Hawaii AU - Hoover, , SR AU - Fodor, RV T2 - BULLETIN OF VOLCANOLOGY DA - 1997/12// PY - 1997/12// DO - 10.1007/s004450050185 VL - 59 IS - 3 SP - 186-197 SN - 0258-8900 KW - gabbro KW - dike KW - xenolith KW - Mauna Kea KW - cumulate KW - magma reservoir ER - TY - JOUR TI - Lizards as Hosts for Immature Ixodes scapularis (Acari: Ixodidae) in North Carolina AU - Levine, Jay F. AU - Apperson, Charles S. AU - Howard, Peter AU - Washburn, Michelle AU - Braswell, Alvin L. T2 - Journal of Medical Entomology AB - Journal Article Lizards as Hosts for Immature Ixodes scapularis (Acari: Ixodidae) in North Carolina Get access Jay F. Levine, Jay F. Levine 1Department of Microbiology, Pathology and Parasitology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606 Search for other works by this author on: Oxford Academic PubMed Google Scholar Charles S. Apperson, Charles S. Apperson 2Department of Entomology, College of Agriculture and Life Sciences, North Carolina State University, Raleigh, NC 27695-7613 Search for other works by this author on: Oxford Academic PubMed Google Scholar Peter Howard, Peter Howard 1Department of Microbiology, Pathology and Parasitology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606 Search for other works by this author on: Oxford Academic PubMed Google Scholar Michelle Washburn, Michelle Washburn 1Department of Microbiology, Pathology and Parasitology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606 Search for other works by this author on: Oxford Academic PubMed Google Scholar Alvin L. Braswell Alvin L. Braswell 3North Carolina State Museum of Natural Sciences, Raleigh, NC 27626-0555 Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Medical Entomology, Volume 34, Issue 6, 1 November 1997, Pages 594–598, https://doi.org/10.1093/jmedent/34.6.594 Published: 01 November 1997 Article history Received: 25 October 1996 Accepted: 04 April 1997 Published: 01 November 1997 DA - 1997/11/1/ PY - 1997/11/1/ DO - 10.1093/jmedent/34.6.594 VL - 34 IS - 6 SP - 594-598 LA - en OP - SN - 1938-2928 0022-2585 UR - http://dx.doi.org/10.1093/jmedent/34.6.594 DB - Crossref ER - TY - JOUR TI - Impact of air mass histories on the chemical climate of Mount Mitchell, North Carolina AU - Ulman, JC AU - Saxena, VK T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Cloud water acidity and ionic content, as measured at the Mount Mitchell (35°44′05″N, 82°17′15″W, 2038 m msl (highest peak in the eastern United States)) State Park observing site, using a passive cloud water collector, are directly influenced by the trajectories of cloud‐forming air masses which pass over areas of varying levels of pollutant emission. Regions of the United States which are emitters of high‐level pollutants, such as SO x and NO x will thus serve to reduce observed p H levels in cloud water samples and raise the levels of acidifying ions, such as sulfate and nitrate. The 48‐hour backward trajectories for all 39 cloud events during the 1993 field season (May 15, 1993 to October 14, 1993) were computed using the hybrid singleparticle Lagrangian integrated trajectories (HY‐SPLIT) model. Three sectors, identified as the polluted sector, from 290° to 65° azimuth relative to the site, the continental sector, 240° to 290° azimuth, and the marine sector, 65° to 240° azimuth, were used to classify the cloud‐forming air masses. The polluted sector was associated with the lowest overall p H averages, with the marine sector following closely behind. The highest average p H values were received from air masses indicated as having crossed the continental and the marine sectors (in combination), with the largest portions of those air mass trajectories passing through the continental sector (exclusively continental sector air masses were also the most frequent). These observations are in agreement with findings in Colorado where aerosols produced by wind erosion were responsible for decreasing the precipitation acidity. DA - 1997/11/20/ PY - 1997/11/20/ DO - 10.1029/97JD01183 VL - 102 IS - D21 SP - 25451-25465 SN - 2169-897X ER - TY - JOUR TI - Comparative effects of poultry and swine waste lagoon spills on the quality of receiving streamwaters AU - Mallin, MA AU - Burkholder, JM AU - McIver, MR AU - Shanks, GC AU - Glasgow, HB AU - Touchette, BW AU - Springer, J T2 - JOURNAL OF ENVIRONMENTAL QUALITY AB - Abstract During July 1995, a poultry waste lagoon ruptured in Duplin County, North Carolina, sending 32.6 million L of chicken waste effluent into a nearby creek and the Northeast Cape Fear River. In August 1995 a breach of a hog waste lagoon released approximately 7.6 million L of waste into a system of blackwater creeks in Brunswick County, North Carolina. The poultry waste spill occurred under high rainfall‐high river flow conditions, while the swine waste lagoon spill occurred during dry conditions. Both spills caused high turbidity and low dissolved oxygen (DO) in receiving waters, and DO levels in the Northeast Cape Fear River displayed a “sag curve” 10 d after the poultry waste spill, reaching a minimum of 1.0 mg L −1 90 km downstream. Both spills delivered high N loads to receiving waters (maxima of 92.1 mg L −1 from the poultry spill and 47.0 mg L −1 from the swine waste spill). Phosphorous concentrations reached 6.0 and 11.5 mg L −1 in receiving waters of the poultry and swine waste spills, respectively. Dense phytoplankton blooms (>100 µg chlorophyll a L −1 ) were measured in the blackwater creeks after the swine spill. High fecal coliform concentrations were delivered by both spills, and concentrations of the pathogenic bacterium Clostridium perfringens ranged up to 40 000 colony‐forming units (CFU) mL −1 in the receiving waters after the poultry spill. In 1995 and 1996 more than 30 animal waste lagoon breaches, overtoppings, and inundations were reported in North Carolina, demonstrating the major pollution potential of these treatment systems. DA - 1997/// PY - 1997/// DO - 10.2134/jeq1997.00472425002600060023x VL - 26 IS - 6 SP - 1622-1631 SN - 0047-2425 ER - TY - JOUR TI - Charge centroid and origin of generated and intrinsic bulk defects at 293 and 100 K in insulated gate field effect transistors AU - Kim, HS AU - Williams, CK AU - Reisman, A T2 - JOURNAL OF APPLIED PHYSICS AB - Intrinsic and generated bulk defects in the gate insulator of silicon insulated gate field effect transistors were examined using a continuous forward-bias pulsed injection technique to inject up to 1017 e/cm2 at 293 and 100 K, for insulator thicknesses ranging between 5.4 and 50.5 nm. The amount of trapping observed at 100 K was about 30 times greater than that at 293 K. The additional trapping at the reduced temperature was determined to come from two sources. One is trapping by existing shallow bulk defects, and the other is an increase in the density of generated bulk defects. The defect generation process is thought to be related to the neutral hole trap becoming unstable during injection, acting as an electron trap. This instability appears to be enhanced as the temperature is reduced to 100 K by a “freeze out’’ effect, or by higher energy carriers that result from a reduction in the thermal scattering. The defect generation rate follows a power law, much like a chemical rate equation, i.e., the rate of defect generation is dependent on the injection current density, much like a chemical reaction is dependent on pressure of the reactive species. The charge centroid of the generated defects, measured from the substrate/oxide interface, was determined at both temperatures and the centroid of the shallow electron traps was determined at 100 K. These were found to be in the range of 6–8 nm at 100 K and 10–16 nm at 293 K. Also, a defect free, or tunneling, region of 2–4 nm extent was determined to exist at each interface. This implies that when the oxide thickness decreases to about 4–8 nm, no threshold voltage shift should result from carrier injection at room, or low temperature, and in fact this behavior was observed in these devices (at least up to 1017 e/cm2 injected). It was found that the shallow traps can be rapidly depopulated by subjecting the devices to ordinary white light during normal device use, pointing to a possible method to improve device reliability at 100 K. DA - 1997/2/1/ PY - 1997/2/1/ DO - 10.1063/1.364087 VL - 81 IS - 3 SP - 1566-1574 SN - 0021-8979 ER - TY - JOUR TI - Tick-raccoon associations and the potential for Lyme disease spirochete transmission in the coastal plain of North Carolina AU - Ouellette, J AU - Apperson, CS AU - Howard, P AU - Evans, TL AU - Levine, JF T2 - JOURNAL OF WILDLIFE DISEASES AB - Raccoons (Procyon lotor) were live-trapped and examined for ticks from July 1990 to July 1993 in the coastal plain of North Carolina on Marine Corps Base, Camp Lejeune, North Carolina (USA). Five species of ixodid ticks were found on 351 (78%) of 449 raccoons. Amblyomma americanum was the most abundant tick found on raccoons. Dermacentor variabilis, Ixodes texanus, and Ixodes scapularis were frequently collected, while Ixodes cookei were rarely collected from raccoons. Tick burdens were not affected by the age, sex, or trap location of captured raccoons. Ticks parasitizing raccoons had varying seasonal patterns of abundance. Amblyomma americanum were generally collected from raccoons year around, but infestation intensities were greatest in summer from June to September. Dermacentor variabilis adults were most abundant in mid-summer while peak numbers of larvae were collected in the fall. Infestation intensities of Ixodes texanus larvae were greatest in fall and winter months while nymphs were most abundant in winter and spring. No males were collected from raccoons, but females were most frequently collected in the spring and declined in abundance in the summer with no specimens collected in the fall or winter. Numbers of I. scapularis adults appeared to reach peak numbers in the fall while larvae and nymphs were most abundant on raccoons in winter. Spirochetes, Borrelia burgdorferi, were identified in a small percentage (0.2%) of host-seeking A. americanum nymphs and adults, and I. scapularis adults by immunofluorescent antibody assays. Similarly, a small percentage (1.9%) of host-associated A. americanum, D. variabilis, I. texanus and I. cookei contained B. burgdorferi. Borrelia burgdorferi spirochetes were cultured from the blood of 23 (26%) of 87 raccoons. DA - 1997/1// PY - 1997/1// DO - 10.7589/0090-3558-33.1.28 VL - 33 IS - 1 SP - 28-39 SN - 1943-3700 KW - raccoons KW - Procyon lotor KW - Amblyomma americanum KW - prevalence KW - infestation intensity KW - Borrelia burgdorferi KW - antibodies ER - TY - JOUR TI - The impact of water temperature on core body temperature of North American river otters (Lutra canadensis) during simulated oil spill recovery washing protocols AU - Stoskopf, M. K. AU - Spelman, L. H. AU - Sumner, P. W. AU - Redmond, D. P. AU - Jochem, W. J. AU - Levine, J. F. T2 - Journal of Zoo and Wildlife Medicine DA - 1997/// PY - 1997/// VL - 28 IS - 4 (Index iss.) SP - 407-412 ER - TY - JOUR TI - Recurrent depletion of benthic oxygen with 4th-order transgressive maxima in the Cretaceous Western Interior Seaway AU - Sethi, PS AU - Leithold, EL T2 - PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY AB - A study was designed to investigate the relationship between depletion of benthic oxygen and 4th-order sea-level change within the Cretaceous Western Interior Seaway of North America. Three 4th-order sea-level change cycles were studied in strata belonging to the Tropic Shale and the Tununk Shale Member of the Mancos Shale in Utah. These sedimentary deposits accumulated within prodeltaic environments. In Utah, strata belonging to all three 4th-order cycles exhibit evidence for depletion of benthic oxygen at times of peak 4th-order transgression and development of condensed sections. The evidence includes decreased intensities of bioturbation, increased CrAl, NiAl, and ZnAl ratios, and decreased MnFe ratios. The data also suggest that depletion of benthic oxygen in the distal section preceeded that in the more proximal one and thus may reflect episodic expansion of an oxygen-depleted water mass(es) from the pelagic to the prodeltaic environment of the seaway. Evidence for subsequent increases in benthic oxygen level with the onset of 4th-order regressions is interpreted to reflect either aggradation of the seafloor above the oxygen-poor water due to sediment accumulation or contraction of the oxygen-depleted water mass from the prodeltaic part of the seaway, or a combination of the two. S/Organic C ratios of strata interpreted to have been deposited under conditions of depleted benthic oxygen are distinctly below 0.4 and thus were not useful for recognition of paleo-oxygen levels in the prodeltaic environment. This study highlights the importance of depletion of benthic oxygen as a mechanism for enhancing preservation of organic carbon in condensed sections on a hundred thousand year time scale. Our results underline the potential for source rock formation in similar prodeltaic deposits of other epicontinental seaways during periods of relatively high sea level and global depletion of benthic oxygen. DA - 1997/2// PY - 1997/2// DO - 10.1016/S0031-0182(96)00104-6 VL - 128 IS - 1-4 SP - 39-61 SN - 1872-616X KW - Cretaceous KW - organic carbon KW - periodicity KW - Western Interior KW - metals KW - sulfur ER - TY - JOUR TI - Persisting learning deficits in rats after exposure to Pfiesteria piscicida AU - Levin, ED AU - Schmechel, DE AU - Burkholder, JM AU - Glasgow, HB AU - Deamer-Melia, NJ AU - Moser, VC AU - Harry, GJ T2 - ENVIRONMENTAL HEALTH PERSPECTIVES AB - Pfiesteria piscicida and other toxic Pfiesteria-like dinoflagellates have been implicated as a cause of fish kills in North Carolina estuaries and elsewhere. Accidental laboratory exposure of humans to P. piscicida has been reported to cause a complex syndrome including cognitive impairment. The current project was conducted to experimentally assess the possibility of cognitive effects of P. piscicida exposure in rats. Samples of water from aquaria in which P. piscicida zoospores were killing fish were frozen, a procedure that has been found to induce encystment. Thawed samples were injected into albino Sprague-Dawley rats. A significant learning impairment was documented in rats administered samples of P. piscicida that were recently frozen. Prolonged storage of Pfiesteria samples diminished the effect. No effect was seen in the recall of a previously learned task, but when the rats were called upon to learn a new task, the Pfiesteria-treated animals showed a significant learning deficit. This effect persisted up to at least 10 weeks after a single injection of Pfiesteria. The Pfiesteria-induced learning deficit did not seem to be associated with any obvious debilitation or health impairment of the exposed rats. Deficits in habituation of arousal and rearing behavior were detected using a functional observational battery. No Pfiesteria-induced effects on blood count and white cell differential or in a standard pathological screening of brain, liver, lung, kidney, and spleen tissue were seen at 2 months after exposure. These studies document a persistent learning impairment in rats after exposure to the dinoflagellate P.piscicida in otherwise physically well-appearing rats. This effect may partially model the symptoms of cognitive impairments that humans have shown after Pfiesteria exposure. DA - 1997/12// PY - 1997/12// DO - 10.2307/3433751 VL - 105 IS - 12 SP - 1320-1325 SN - 0091-6765 KW - dinoflagellates KW - learning KW - memory KW - persisting KW - Pfiesteria KW - radial-arm maze KW - toxic ER - TY - JOUR TI - Particle trajectories above sinusoidal terrain AU - Stout, J. E. AU - Janowitz, G. S. T2 - Quarterly Journal of the Royal Meteorological Society DA - 1997/// PY - 1997/// VL - 123 IS - 543 pt.A SP - 1829-1840 ER - TY - JOUR TI - Maize growth: assessing the effects of global warming and CO2 fertilization with crop models AU - Dhakhwa, GB AU - Campbell, CL AU - LeDuc, SK AU - Cooter, EJ T2 - AGRICULTURAL AND FOREST METEOROLOGY AB - Projected future climate change scenarios derived from two General Circulation Models (GCMs): Geophysical Fluid Dynamics Laboratory (GFDL) and United Kingdom Meteorological Office (UKMO), and two crop models: Crop Estimation through Resources and Environmental Synthesis (CERES), and Erosion/Productivity Impact Calculator (EPIC), were considered to assess the climate change impact on the yield and biomass of maize. Climate change scenarios included changes in temperature, precipitation and solar radiation from two GCMs interpolated to 1° × 1° grid cells in the central Piedmont in North Carolina. Changes in mean monthly temperature and precipiation from the GCMs were used to adjust observed daily climate records from 1949–1988. There is convincing evidence that future temperature linked to global warming might be characterized by asymmetric change between daily daytime maxima and daily nighttime minima. Two hypotheses regarding how GCM temperature would alter observational record were examined. The first assumed that daytime and nighttime warming occurs symmetrically, i.e., maximum and minimum temperatures are raised equally. The second hypothesis assumed that nightime minima change is three times greater than daytime maxima change and the change in mean diurnal temperature range is approximately equal to the change in daily mean temperature. For the equal day-night warming scenario, when only the effects of climate change (i.e., changes in temperature, precipitation and solar radiation) were considered, simulations with CERES and EPIC indicated substantial losses in maize grain yield and tolar above ground biomass with both the GCM scenarios. For the asymmetric warming, the reduction in biomass and yield due to climate change was less than that obtained with symmetric warming. Simulated maize yield and biomass with CERES and EPIC increased when only effects due to CO2-fertilization were considered. The inclusion of CO2 fertilization effects with those due to climate change resulted in higher biomass and yield compared to values obtained with effects of climate change alone. When CERES was used with the GFDL scenario, and the effects of CO2 fertilization and the climate change were combined, no difference in simulated yield was found between the two hypotheses; only an 8% difference in aboveground biomass was found when the UKMO scenario was used. When EPIC was used, the differential day-night warming hypothesis resulted in 9–13% less reduction in biomass and yield than did the use of the equal day-night warming hypothesis. DA - 1997/12/1/ PY - 1997/12/1/ DO - 10.1016/S0168-1923(97)00030-0 VL - 87 IS - 4 SP - 253-272 SN - 1873-2240 KW - biomass KW - global warming KW - CO2 KW - North Carolina ER - TY - JOUR TI - Lateral variations among populations of stained benthic foraminifera in surface sediments of the North Carolina continental shelf (USA) AU - Lueck, KLO AU - Snyder, SW T2 - JOURNAL OF FORAMINIFERAL RESEARCH AB - Other| January 01, 1997 Lateral variations among populations of stained benthic foraminifera in surface sediments of the North Carolina continental shelf (U.S.A.) Katrina Leigh Owens Lueck; Katrina Leigh Owens Lueck East Carolina University, Department of Geology, Greenville, NC, United States Search for other works by this author on: GSW Google Scholar Scott W. Snyder Scott W. Snyder Search for other works by this author on: GSW Google Scholar Author and Article Information Katrina Leigh Owens Lueck East Carolina University, Department of Geology, Greenville, NC, United States Scott W. Snyder Publisher: Cushman Foundation for Foraminiferal Research First Online: 03 Mar 2017 Online ISSN: 1943-264X Print ISSN: 0096-1191 GeoRef, Copyright 2004, American Geological Institute. Journal of Foraminiferal Research (1997) 27 (1): 20–41. https://doi.org/10.2113/gsjfr.27.1.20 Article history First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Katrina Leigh Owens Lueck, Scott W. Snyder; Lateral variations among populations of stained benthic foraminifera in surface sediments of the North Carolina continental shelf (U.S.A.). Journal of Foraminiferal Research 1997;; 27 (1): 20–41. doi: https://doi.org/10.2113/gsjfr.27.1.20 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 SocietyJournal of Foraminiferal Research Search Advanced Search This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access. DA - 1997/1// PY - 1997/1// DO - 10.2113/gsjfr.27.1.20 VL - 27 IS - 1 SP - 20-41 SN - 0096-1191 ER - TY - JOUR TI - Interaction between surface wind and ocean circulation in the Carolina Capes in a coupled low-order model AU - Xie, L AU - Pietrafesa, LJ AU - Raman, S T2 - CONTINENTAL SHELF RESEARCH AB - Abstract Interactions between surface winds and ocean currents over an east-coast continental shelf are studied using a simple mathematical model. The model physics includes cross-shelf advection of sea surface temperature (SST) by Ekman drift, upwelling due to Ekman transport divergence, differential heating of the low-level atmosphere by a cross-shelf SST gradient, and the Coriolis effect. Additionally, the effects of diabatic cooling of surface waters due to air-sea heat exchange and of the vertical density stratification on the thickness of the upper ocean Ekman layer are considered. The model results are qualitatively consistent with observed wind-driven coastal ocean circulation and surface wind signatures induced by SST. This simple model also demonstrates that two-way air-sea interaction plays a significant role in the subtidal frequency variability of coastal ocean circulation and mesoscale variability of surface wind fields over coastal waters. DA - 1997/10// PY - 1997/10// DO - 10.1016/S0278-4343(97)00024-1 VL - 17 IS - 12 SP - 1483-1511 SN - 0278-4343 ER - TY - JOUR TI - Impact of stratospheric volcanic aerosols on climate: Evidence for aerosol shortwave and longwave forcing in the southeastern US AU - Saxena, VK AU - Yu, SC AU - Anderson, J T2 - ATMOSPHERIC ENVIRONMENT AB - Major volcanic eruptions inject massive amounts of dust and gases into the lower stratosphere and upper troposphere. Stratospheric volcanic aerosols can scatter incoming solar radiation to space, increasing planetary albedo, reducing the total amount of solar energy reaching the troposphere and the earth's surface, and decreasing the daytime maximum temperature (aerosol shortwave forcing). They can also absorb and scatter outgoing terrestrial longwave radiation, increasing the nighttime minimum surface temperature (longwave forcing). However, persuasive evidence of climate response to this forcing has thus far been lacking. Here we examine patterns of annual and seasonal variations in mean maximum and minimum temperature trend during the periods 1992–1994 and 1985–1987 relative to that during the period 1988–1990 at 47 stations in the southeastern U.S. for evidence of such climate responses. The stratospheric volcanic aerosol optical depths over the southeastern U.S. during the period 1985–1994 were inferred from the Stratospheric Aerosol and Gases Experiment (SAGE) 11 satellite extinction measurement. After the long-term trend signals are removed, it is shown that the dominant decreasing trend of mean maximum temperature and the dominant increasing trend of mean minimum temperature over periods 1992–1994 and 1985–1987 relative to that over the period 1988–1990 are consistent with the distribution of stratospheric volcanic aerosols and predictions from aerosol radiative forcing in the southeastern U.S. DA - 1997/12// PY - 1997/12// DO - 10.1016/S1352-2310(97)00244-6 VL - 31 IS - 24 SP - 4211-4221 SN - 1352-2310 KW - aerosol KW - radiative forcing KW - minimum and maximum temperature KW - volcano KW - stratosphere ER - TY - JOUR TI - Footprint considerations in BOREAS AU - Kaharabata, SK AU - Schuepp, PH AU - Ogunjemiyo, S AU - Shen, S AU - Leclerc, MY AU - Desjardins, RL AU - MacPherson, JI T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Comparisons of observations of concentration or flux from platforms at various heights, such as tower and aircraft, must take into account differences in the location and extent of upwind surface source or sink areas which affect the individual observations, with their physical and biological characteristics. Such “footprint” estimates are based on solutions of the diffusion/advection equation which have not previously been evaluated over a boreal ecosystem. In order to adjust an analytical footprint model within the surface layer above forest canopies typical for the Boreal Ecosystem‐Atmosphere Study (BOREAS) sites, 29 tracer gas release experiments were carried out between August 30 and September 9, 1994, at three tower sites in the northern study area (NSA). Sulphur hexafluoride (SF 6 ) was released from point sources at various upwind distances from the towers under various meteorological, terrain, and release conditions. Wind, temperature, and stability parameters, during each release period, were used as input into calculations of vertical concentration profiles sampled at the towers, based on a three‐dimensional diffusion model. Predictions of concentration profiles, or back calculation of source strength from observed profiles, were in good agreement with observed concentrations or actual release rates, respectively. The diffusion model was then used to compute footprint estimates for stable to unstable conditions, for tower and aircraft‐based observation platforms. They show spatially constrained footprints in the surface layer, due to effective vertical coupling, so observations from towers and low‐flying aircraft must be expected to be very site specific, and scaling up to larger areas will have to be done with careful consideration of surface mosaics. Our study also included footprint estimates made for airborne observations above the surface layer, based on large‐eddy simulations over “BOREAS‐like” terrain, for boundary layer structures comparable to those observed in BOREAS. They document the progressive decoupling of airborne observations from the surface features at these heights. DA - 1997/12/26/ PY - 1997/12/26/ DO - 10.1029/97JD02559 VL - 102 IS - D24 SP - 29113-29124 SN - 2169-8996 ER - TY - JOUR TI - Enhancing estuarine retention of planktonic larvae by tidal currents AU - Chen, YH AU - Shaw, PT AU - Wolcott, TG T2 - ESTUARINE COASTAL AND SHELF SCIENCE AB - To complete their life history, planktonic larvae of many marine species must be retained in or return to estuarine nursery grounds despite net downstream flows. Interactions between tidal currents and behaviour (vertical migration) of larvae are assumed to play an important role in upstream transport or station-holding, but the effects of tidal currents alone have not received close examination. To elucidate their effects, passive particles were followed numerically in a model of idealized flow. The model basin was patterned after the Newport River Narrows, part of a small coastal-plain estuary with simple bathymetry and a well-studied example of larval retention (mud crabs,Rhithropanopeus harrisii). The flow field, governed by an analytical solution of the linearized equation of motion, was forced by oscillating tidal currents at the seaward end of the estuarine channel, and its energy was dissipated by bottom friction and eddy diffusion. Particles released at various locations showed a net upstream drift, produced by the combined effects of: (1) shear in the vertical profile of horizontal velocity; and (2) tidally-induced vertical motion. Velocity of upstream drift could partially offset net downstream transport by river flow. This velocity increased with distance downstream, providing a mechanism tending to stabilize positions of larvae in the basin. Tidal vertical migration of mud crab larvae in nature is in phase with, and presumably reinforced by, the predicted tide-induced vertical motions of the water. The passive, tidally-induced upstream drift could provide an important mechanism, in addition to larval behaviour, for the retention of larvae in estuaries. DA - 1997/10// PY - 1997/10// DO - 10.1006/ecss.1996.0217 VL - 45 IS - 4 SP - 525-533 SN - 0272-7714 KW - particle motion KW - passive transport KW - tidal currents KW - North Carolina Coast ER - TY - JOUR TI - Effect of land-use pattern on the development of low-level jets AU - Wu, YH AU - Raman, S T2 - JOURNAL OF APPLIED METEOROLOGY AB - Land-use patterns are a major factor that causes land surface heterogeneities, which in turn influence the development of mesoscale circulations. In the present study, effects of land-use patterns on the formation and structure of mesoscale circulations were investigated using the North Carolina State University mesoscale model linked with the soil–vegetation system. The Midwest type of low-level jet (LLJ) was successfully generated in the model simulation. Characteristics of the LLJ generated in the numerical experiments are consistent with observations. The results suggest that land surface heterogeneities could have significant impacts on the formation and the maintenance of the LLJ. DA - 1997/5// PY - 1997/5// DO - 10.1175/1520-0450(1997)036<0573:EOLUPO>2.0.CO;2 VL - 36 IS - 5 SP - 573-590 SN - 0894-8763 ER - TY - JOUR TI - Effect of Osmotic Shock on Protein Synthesis of Oyster Hemocytes In Vitro AU - Tirard, C.T AU - Grossfeld, R.M AU - Levine, J.F AU - Kennedy-Stoskopf, S T2 - Comparative Biochemistry and Physiology Part A: Physiology AB - Because marine bivalves are osmoconformers, their cells may be exposed to widely fluctuating osmolality in some habitats. In vitro studies were conducted to evaluate the effect of changes in salinity on protein synthesis of oyster hemocytes. Increasing salinity from a control value of 20–25 ppt to 32–98 ppt decreased the rate of incorporation of amino acid into protein, but did not qualitatively alter the pattern of protein synthesis. On the other hand, decreasing salinity to 3.5–4 ppt not only decreased the rate of protein synthesis, but also altered the types of protein produced. At least a third of the cells remained viable at low salinity and resumed the control pattern of protein synthesis within hours after return to the normal medium. The response to hypoosmotic shock was different from the response to a hyperthermic shock, each stressor inducing expression of a characteristic set of proteins. Preferential synthesis of these proteins may represent an adaptation to preserve or restore oyster cell functions under adverse conditions. DA - 1997/1// PY - 1997/1// DO - 10.1016/s0300-9629(96)00115-6 VL - 116 IS - 1 SP - 43-49 J2 - Comparative Biochemistry and Physiology Part A: Physiology LA - en OP - SN - 0300-9629 UR - http://dx.doi.org/10.1016/S0300-9629(96)00115-6 DB - Crossref KW - hemocytes KW - osmotic KW - oysters KW - salinity KW - stress proteins ER - TY - JOUR TI - Contribution of biogenic nitric oxide in urban ozone: Raleigh, NC, as a case study AU - Aneja, VP AU - Roelle, P AU - Robarge, WP T2 - ATMOSPHERIC ENVIRONMENT AB - Anthropogenic emissions from industrial and automotive sources within the confines of the city of Raleigh, NC have been documented by the North Carolina Department of Environment, Health and Natural Resources, Division of Environmental Management, but no direct biogenic emissions of nitric oxide (NO) from soils has yet been measured. In this study, emissions of NO were measured in Raleigh, NC, and its surrounding suburbs, in an attempt to determine the portion of the total NOx ( = NO + NO2) budget which can be attributed to biogenic sources. Residential and commercial lawns, and golf courses receiving normal fertilizer applications were chosen as the primary biogenic source of NO. Soil NO fluxes were measured using a dynamic chamber technique from 11 sites and ranged in value (hourly averages calculated from 15 min readings) from 1.24 to 23.7 ng N m−2 s−1. These hour averages were then combined with estimates of lawn acreage within the city proper, and in the surrounding suburbs, in order to develop a budget for giogenic NO emissions in Raleigh. This budget was then compared to the budget used in the Environmental Protection Agency's (EPA) Regional Oxidant Model (ROM) for photochemical modeling. Results from this comparison suggest that less than 1 % of the total NOx budget for Raleigh, NC is emitted by natural processes, and that approximately 1.2% of the nitrogen applied as fertilizer is lost via soil NO emissions. Thus, the effects of biogenic NO may be neglected in the development of a reliable plan for reducing ozone in the urban atmosphere. DA - 1997/5// PY - 1997/5// DO - 10.1016/S1352-2310(96)00282-8 VL - 31 IS - 10 SP - 1531-1537 SN - 1352-2310 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0030616154&partnerID=MN8TOARS KW - biogenic nitric oxide KW - urban source strength ER - TY - JOUR TI - Characterization of non-methane hydrocarbons in the rural southeast United States AU - Hagerman, LM AU - Aneja, VP AU - Lonneman, WA T2 - ATMOSPHERIC ENVIRONMENT AB - Measurements of non-methane hydrocarbons, as well as ozone, meteorological and trace gas data, made at four rural sites located within the southeastern United States as a part of the Southern Oxidants Study are compared. The C2–C10 hydrocarbons were obtained during the 1200–1300 local time period, once every six days from September 1992 through October 1993. The light molecular weight alkanes (ethane, propane, n-butane, iso-butane, ethene and acetylene) display a seasonal variation of a winter maximum and summer minimum. Isoprene was virtually non-existent during the winter at all sites, and averaged from 9.8 ppbC (Yorkville, Georgia) to 21.15 ppbC (Centreville, Alabama) during the summer. The C10 terpene concentration was largest during the summer period with averages ranging between 3.19 ppbC (Centreville, Alabama) and 6.38 ppbC (Oak Grove, Mississippi); winter time concentrations ranged from 1.25 to 1.9 ppbC for all sites. Propylene-equivalent concentrations were calculated to account for differences in reaction rates between the hydroxyl radical and individual hydrocarbons, and to thereby estimate their relative contribution to ozone, especially in regard to the highly reactive biogenic compounds such as isoprene. The propy-equivalent concentrations from the biogenics represent at least 65% of the total non-methane hydrocarbon sum at these four sites during the summer season. A plot of ozone versus NOγ-NO highlights the NOx limited relationship of this region. DA - 1997/12// PY - 1997/12// DO - 10.1016/S1352-2310(97)00223-9 VL - 31 IS - 23 SP - 4017-4038 SN - 1352-2310 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0031543513&partnerID=MN8TOARS KW - speciated non-methane hydrocarbons KW - rural KW - biogenics KW - annual measurements ER - TY - JOUR TI - Changes in stratospheric aerosol parameters over 105-135 degrees E longitude due to eruption of Mount Pinatubo AU - Lin, NH AU - Saxena, VK T2 - JOURNAL OF AEROSOL SCIENCE AB - The eruption of Mt Pinatubo (15.14°N, 120.35°E) in the Philippines on 15 June 1991 produced the largest volcanic effluents into the stratosphere as observed by satellite measurements. In this paper we demonstrate the application of an inversion technique to satellite observations to infer the stratospheric aerosol size distributions before and after the eruption. The U.S.A. NASA SAGE (Stratospheric Aerosol and Gas Experiment) 11 satellite data were used. As a result, the stratospheric aerosol size distributions were found to be bimodal due to the addition of larger particles from Mt Pinatubo ejection. In addition, aerosol parameters such as extinction coefficient, effective radius, total surface area, and mass loading were used to track the northward and southward dispersion of Pinatubo volcanic plume unmistakably. For example, by 18 July 1991, the Pinatubo plume had reached as high as 22 km in the stratosphere above Taiwan area. The extinction profiles for September and October 1991 cases were enhanced about two orders in magnitude at the altitude of 20–24 km owing to Pinatubo aerosols. Regarding the transport in the southern hemisphere, for five months after eruption, the plume had reached the Antarctic stratosphere, and dispersed vertically as high as 40 km. In middle Antarctic stratosphere, the aerosol extinctions were increased in general by an order of 103-105 due to the intrusion of Pinatubo plume. The second mode at 0.5 μm was found compared with the one at less than 0.1 μm, generally found in background stratosphere. DA - 1997/6// PY - 1997/6// DO - 10.1016/S0021-8502(96)00463-6 VL - 28 IS - 4 SP - 697-712 SN - 0021-8502 ER - TY - JOUR TI - A laboratory study of the urban heat island in a calm and stably stratified environment .2. Velocity field AU - Lu, J AU - Arya, SP AU - Snyder, WH AU - Lawson, RE T2 - JOURNAL OF APPLIED METEOROLOGY AB - A fully turbulent, low-aspect-ratio buoyant plume with no initial momentum under calm and stably stratified conditions is produced in a convection tank. The plume is generated by a circular heat island at the bottom of the tank. Two analytical models, a bulk convection model and a hydrostatic model, are developed to formulate similarity relations for the low-aspect-ratio plume. The convective velocity scale wD, suggested by the analytical models, is used as the similarity parameter for both the mean velocity and standard deviations of velocity fluctuations. The normalized standard deviations of horizontal and vertical velocities agree with each other for two heating rates, as well as with field observations in the center of Sapporo, Japan. The suggested scaling and empirical relations based on our experimental results may be applied to the velocity fields of other low-aspect-ratio plumes in calm and stably stratified environments. Further investigations are recommended to confirm the results of the current study. DA - 1997/10// PY - 1997/10// DO - 10.1175/1520-0450(1997)036<1392:ALSOTU>2.0.CO;2 VL - 36 IS - 10 SP - 1392-1402 SN - 0894-8763 ER - TY - JOUR TI - A laboratory study of the urban heat island in a calm and stably stratified environment .1. Temperature field AU - Lu, J AU - Arya, SP AU - Snyder, WH AU - Lawson, RE T2 - JOURNAL OF APPLIED METEOROLOGY AB - An extensive and systematic water-tank study was performed to simulate the urban heat island under a calm and stably stratified environment. The objective was to examine the mean-temperature field, mixing height, and heat-island intensity as functions of surface heating rates, heat-island sizes, and ambient temperature gradients. The scaling parameters for the temperature field associated with the heat-island plume are the diameter D, surface heating rate H0, and Brunt–Väisälä frequency N of the ambient stratification. The induced plume was turbulent, and the Froude number was found to be the most important similarity parameter. The differences between low- and high-aspect-ratio plumes are discussed, and simple theoretical models are proposed for low-aspect-ratio plumes. The experimental results generally confirm the theoretical predictions and agree reasonably well with field observations, in spite of several limitations of the laboratory simulation. The mean-temperature distributions are found to have a universal shape that is a function of location only. The results are described in two papers. In this paper, the temperature fields are described. Part II describes the velocity fields and develops analytical models that apply to low-aspect-ratio plumes. DA - 1997/10// PY - 1997/10// DO - 10.1175/1520-0450(1997)036<1377:ALSOTU>2.0.CO;2 VL - 36 IS - 10 SP - 1377-1391 SN - 0894-8763 ER - TY - JOUR TI - A chemical mass balance analysis of nonmethane hydrocarbon emissions in North Carolina AU - Lawrimore, JH AU - Aneja, VP T2 - CHEMOSPHERE AB - The EPA's Chemical Mass Balance Receptor Model (CMB7) was used for analysis of nonmethane hydrocarbon source-receptor relationships in the Raleigh, North Carolina Metropolitan Statistical Area (MSA). Three hour integrated ambient samples collected 15 km southeast of downtown Raleigh from 5–8 AM weekdays during August, 1993 were analyzed for speciated hydrocarbons and used as inputs in the model. Additional samples collected from 12–3 PM and 5–8 PM were also analyzed. CMB results for four source profiles, i.e. roadway, whole gas, surface coating, and isoprene were compared with the State of North Carolina's seasonally adjusted emission inventory for anthropogenic and biogenic hydrocarbon emissions. The Biogenic Emission Inventory System (BETS) was used to estimate isoprene emissions for a typical summer day in the Raleigh area. CMB results using average concentrations of the 5–8 AM samples were similar to both the anthropogenic and biogenic emission inventory. Mass balance attributed 50.5% of total nonmethane organic carbon to roadway sources, 17.0% to surface coatings, and 4.0% to isoprene sources during the 5–8 AM sampling period; compared to the emission inventory which apportioned 47.5% to mobile sources, 14.0% to surface coating sources and 6.0% to isoprene sources during the same period. Afternoon and early evening samples were used to determine the diurnal profile for isoprene and roadway sources for comparison with emission inventory profiles. CMB results showed roadway source emissions decrease from morning to the afternoon and remain relatively constant from the afternoon to early evening. DA - 1997/12// PY - 1997/12// DO - 10.1016/S0045-6535(97)00321-4 VL - 35 IS - 11 SP - 2751-2765 SN - 0045-6535 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0030833965&partnerID=MN8TOARS ER - TY - JOUR TI - The role of radiative transfer in maintaining the Indian summer monsoon circulation AU - Leach, MJ AU - Raman, S AU - Mohanty, UC AU - Madala, RV T2 - PURE AND APPLIED GEOPHYSICS DA - 1997/6// PY - 1997/6// DO - 10.1007/s000240050043 VL - 149 IS - 3 SP - 601-622 SN - 0033-4553 KW - atmospheric radiative transfer KW - circulation KW - Indian summer monsoon KW - thermal forcing ER - TY - JOUR TI - Redescription of the holotype of Dryptosaurus aquilunguis (Dinosauria: Theropoda) from the Upper Cretaceous of New Jersey. AU - Carpenter, K AU - Russell, D AU - Baird, D AU - Denton, R T2 - JOURNAL OF VERTEBRATE PALEONTOLOGY AB - ABSTRACT The skeleton of the enigmatic theropod Dryptosaurus aquilunguis is redescribed in light of the many new theropods named since Cope's original description in 1866. Unfortunately, the fragmentary nature of the single known skeleton makes comparison with other theropods difficult. Historically, Dryptosaurus has been placed, at one time or another, in the theropod families Coeluridae, Deinodontidae, Megalosauridae, Tyrannosauridae, and its own family, Dryptosauridae. Most of these assignments have been based upon superficial resemblances to various members of those families. Reexamination of the specimen indicates the presence of unique serrations on the maxillary teeth, a large ungual/humeral ratio, the probable presence of a high, centrally located ascending process on the astragalus, and a non-arctometatarsal. These features indicate that Dryptosaurus is a unique theropod and should be placed in its own family, Dryptosauridae. DA - 1997/9// PY - 1997/9// DO - 10.1080/02724634.1997.10011003 VL - 17 IS - 3 SP - 561-573 SN - 1937-2809 ER - TY - JOUR TI - Rapid subduction of organic matter by maldanid polychaetes on the North Carolina slope AU - Levin, L AU - Blair, N AU - DeMaster, D AU - Plaia, G AU - Fornes, W AU - Martin, C AU - Thomas, C T2 - JOURNAL OF MARINE RESEARCH AB - In situ tracer experiments conducted on the North Carolina continental slope reveal that tube-building worms (Polychaeta: Maldanidae) can, without ingestion, rapidly subduct freshly deposited, algal carbon ( 13 C-labeled diatoms) and inorganic materials (slope sediment and glass beads) to depths of 10 cm or more in the sediment column. Transport over 1.5 days appears to be nonselective but spatially patchy, creating localized, deep hotspots. As a result of this transport, relatively fresh organic matter becomes available soon after deposition to deep-dwelling microbes and other infauna, and both aerobic and anaerobic processes may be enhanced. Comparison of tracer subduction with estimates from a diffusive mixing model using 234 Th-based coefficients, suggests that maldanid subduction activities, within 1.5 d of particle deposition, could account for 25-100% of the mixing below 5 cm that occurs on 100-day time scales. Comparisons of community data from the North Carolina slope for different places and times indicate a correlation between the abundance of deep-dwelling maldanids and the abundance and the dwelling depth in the sediment column of other infauna. Pulsed inputs of organic matter occur frequently in margin environments and maldanid polychaetes are a common component of continental slope macrobenthos. Thus, the activities we observe are likely to be widespread and significant for chemical cycling (natural and anthropogenic materials) on the slope. We propose that species like maldanids, that rapidly redistribute labile organic matter within the seabed, probably function as keystone resource modifiers. They may exert a disproportionately strong influence (relative to their abundance) on the structure of infaunal communities and on the timing, location and nature of organic matter diagenesis and burial in continental margin sediments. DA - 1997/5// PY - 1997/5// DO - 10.1357/0022240973224337 VL - 55 IS - 3 SP - 595-611 SN - 0022-2402 ER - TY - JOUR TI - Nitrogen oxide flux from an agricultural soil during winter fallow in the upper coastal plain of North Carolina, USA AU - Aneja, VP AU - Holbrook, BD AU - Robarge, WP T2 - JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION AB - Abstract Incorporation of the remaining crop residue, including the root system, of grain (soybean and corn) and fiber (cotton) crops into the soil following harvest is a common agricultural practice. The crop residue represents a substantial portion of nitrogen initially applied as fertilizer, and thus is a potential source of nitrogen for NO emissions during the winter fallow period. Fluxes of NO and NO2 were measured from fallow fields from February 7 to March 23, 1994, using a dynamic chamber technique (ambient air as the carrier gas). Average NO flux rates, as a function of previous crop residue, were 9.2 (range –4.2 to 76) ng–N m–2 s–1 for soybean, 6.1 (range –11.7 to 110) ng–N m–2 s–1 for cotton, and 4.7 (range –0.2 to 40) ng–N m–2 s–1 for corn. Maximum NO fluxes were observed in mid–morning when soil temperatures were lowest. Minimum NO flux occurred after mid–afternoon when soil temperature reached a maximum. The decrease in NO flux with increase in soil temperature (5 cm depth) reflected the existence of a NO compensation concentration (i.e., the rate for the NO consumption reactions continued to increase with increase in temperature). NO2 deposition was calculated for 92% of the data points, with no trend in deposition between the three fields and their corresponding crop residue. These results indicate that significant fluxes of NO are generated from fallow agricultural fields following incorporation of the residue from the previous crop. DA - 1997/7// PY - 1997/7// DO - 10.1080/10473289.1997.10463933 VL - 47 IS - 7 SP - 800-805 SN - 2162-2906 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0031194163&partnerID=MN8TOARS ER - TY - JOUR TI - Heat units to predict tomato harvest in the southeast USA AU - Perry, KB AU - Wu, YH AU - Sanders, DC AU - Garrett, JT AU - Decoteau, DR AU - Nagata, RT AU - Dufault, RJ AU - Batal, KD AU - Granberry, DM AU - Mclaurin, WJ T2 - AGRICULTURAL AND FOREST METEOROLOGY AB - Abstract Planting and first harvest dates of tomato ( Lycopersicon esculentum Mill.) from 2 seasons in 3 years at eight locations in Georgia, North Carolina and South Carolina formed 38 environments which were used to determine the most reliable method to predict fast harvest date of tomato based on daily maximum and minimum air temperature. Eleven methods of calculating heat units were chosen for comparison based on their performance as described in the literature. The most reliable method was defined as the one with the smallest coefficient of variation (CV). CVs were calculated for each method over both seasons and locations, for each season over all locations, each location over all seasons, and for each season at each location. All heat unit summation methods had smaller coefficients of variation (CV) than the standard method of counting days from planting to first harvest. Heat unit summation methods improved harvest date prediction accuracy compared with the counting day method for tomatoes in the South Atlantic Coast (SAC) region. Prediction using location/season specific models were less variable than the models over all seasons and locations. Incorporating daylength improved model prediction accuracy when applied over all locations and seasons, all locations by season, and all seasons by location. Based on the results of this study, the heat unit summation technique recommended for this region (where the location and season specific models are not available) is the reduced ceiling method multiplied by daylength. DA - 1997/4// PY - 1997/4// DO - 10.1016/S0168-1923(96)02361-1 VL - 84 IS - 3-4 SP - 249-254 SN - 0168-1923 KW - heat units KW - tomato harvest KW - southeast USA KW - air temperature ER - TY - JOUR TI - Comparison of four different stomatal resistance schemes using FIFE observations AU - Niyogi, DS AU - Raman, S T2 - JOURNAL OF APPLIED METEOROLOGY AB - Stomatal resistance (Rs) calculation has a major impact on the surface energy partitioning that influences diverse boundary layer processes. Present operational limited area or mesoscale models have the Jarvis-type parameterization, whereas the microscale and the climate simulation models prefer physiological schemes for estimating Rs. The pivotal question regarding operational mesoscale models is whether an iterative physiological scheme needs to be adopted ahead of the analytical Jarvis-type formulation. This question is addressed by comparing the ability of three physiological schemes along with a typical Jarvis-type scheme for predicting Rs using observations made during FIFE. The data used is typical of a C4-type vegetation, predominant in regions of high convective activity such as the semiarid Tropics and the southern United States grasslands. Data from three different intensive field campaigns are analyzed to account for vegetation and hydrological diversity. It is found that the Jarvis-type approach has low variance in the outcome due to a poor feedback for the ambient changes. The physiological models, on the other hand, are found to be quite responsive to the external environment. All three physiological schemes have a similar performance qualitatively, which suggests that the vapor pressure deficit approach or the relative humidity descriptor used in the physiological schemes may not yield different results for routine meteorological applications. For the data considered, the physiological schemes had a consistently better performance compared to the Jarvis-type scheme in predicting Rs outcome. All four schemes can, however, provide a reasonable estimate of the ensemble mean of the samples considered. A significant influence of the seasonal change in the minimum Rs in the Jarvis-type scheme was also noticed, which suggests the use of nitrogen-based information for improving the performance of the Jarvis-type scheme. A possible interactive influence of soil moisture on the capabilities of the four schemes is also discussed. Overall, the physiological schemes performed better under higher moisture availability. DA - 1997/7// PY - 1997/7// DO - 10.1175/1520-0450(1997)036<0903:COFDSR>2.0.CO;2 VL - 36 IS - 7 SP - 903-917 SN - 0894-8763 ER - TY - JOUR TI - A Retrospective Case-Control of Acute Renal Failure in 99 Dogs AU - Vaden, Shelly L. AU - Levine, Jay AU - Breitschwerdt, Edward B. T2 - Journal of Veterinary Internal Medicine AB - The objective of this study was to evaluate retrospectively demographic and clinicopathologic factors that may be associated with the diagnosis and outcome of acute renal failure (ARF) in dogs presented to a large referral hospital. Medical records of dogs presented to the hospital were searched for a diagnosis of ARF. The diagnosis of ARF was based on clinical signs, renal imaging findings, and clinicopathologic data and, in most cases, was confirmed by histopathology, prior serum creatinine concentrations, response to therapy, and known recent nephrotoxin exposure or ischemic event. Demographics, selected clinicopathologic findings, and concurrent disorders that may have been associated with development of ARF were extracted from these records. A reference population was derived from 481 dogs presenting to the same hospital. Demographic data also were collected from these medical records. The demographic factors associated with a diagnosis of ARF and the factors associated with outcome of ARF were assessed by reviewing a series of multiple logistic regression models. Conclusions from this study were as follows: (1) Intact male dogs and nonsporting dogs were more likely to develop ARF and be admitted to the teaching hospital. (2) Dogs with severe azotemia (serum creatinine concentration > 10 mg/dL), hypocalcemia (<8.6 mg/ dL), and proteinuria were less likely to survive ARF and be discharged from the hospital. (3) Dogs that survived in the hospital for more than 5 days were more likely to recover and be discharged from the hospital. DA - 1997/3// PY - 1997/3// DO - 10.1111/j.1939-1676.1997.tb00074.x VL - 11 IS - 2 SP - 58-64 LA - en OP - SN - 0891-6640 1939-1676 UR - http://dx.doi.org/10.1111/j.1939-1676.1997.tb00074.x DB - Crossref ER - TY - JOUR TI - Isotopic stratigraphy of Amazon fan sediments AU - Showers, W. J. AU - Schneider, R. AU - Mikkelson, N. AU - Maslin, M. T2 - Proceedings of the Ocean Drilling Program DA - 1997/// PY - 1997/// VL - 155 IS - 1997 SP - 281-303 ER - TY - JOUR TI - A numerical study of the response of Tropical Pacific SST to atmospheric forcing AU - Liu, X. AU - Morrison, J.M. AU - Xie, L. T2 - Mausam DA - 1997/// PY - 1997/// VL - 45 IS - 4 SP - 657-668 ER - TY - JOUR TI - Uncertainty in the specification of surface characteristics: A study of prediction errors in the boundary layer AU - Alapaty, K AU - Raman, S AU - Niyogi, DS T2 - BOUNDARY-LAYER METEOROLOGY DA - 1997/3// PY - 1997/3// DO - 10.1023/A:1017166907476 VL - 82 IS - 3 SP - 473-500 SN - 0006-8314 KW - uncertainty KW - boundary layer KW - surface characteristics KW - prediction errors ER - TY - JOUR TI - Inter-monsoonal changes in the T-S properties of the near-surface waters of the northern Arabian Sea AU - Morrison, JM T2 - GEOPHYSICAL RESEARCH LETTERS AB - The Arabian Sea experiences extremes in atmospheric forcing that lead to the greatest seasonal variability in any ocean. During 1995, 6 cruises were carried out within the northern Arabian Sea. The data collected represent the first consistent dataset covering an entire monsoonal cycle. Ocean soundings of temperature and salinity from these cruises are used to characterize variability of water masses in the surface layers associated with monsoonal forcing. This paper documents the role of advection versus local water mass modification on seasonal extremes in T‐S in near‐surface waters of the Arabian Sea. Seasonal changes are associated with seasonal heating, advection of waters from the Oman upwelling zone, varying of mixed‐layer depth due to Ekman pumping in the central basin and mixing of high‐salinity waters from Persian Gulf. DA - 1997/11/1/ PY - 1997/11/1/ DO - 10.1029/97GL01876 VL - 24 IS - 21 SP - 2553-2556 SN - 0094-8276 ER - TY - JOUR TI - Cellular convection embedded in the convective planetary boundary layer surface layer AU - DeCroix, D. S. AU - Lin, Y. L. AU - Schowalter, D. G. T2 - Journal of Wind Engineering and Industrial Aerodynamics DA - 1997/// PY - 1997/// VL - 67-68 IS - 1997 Apr./June SP - 387-401 ER - TY - JOUR TI - Predator and shelter-size effects on coral reef fish and spiny lobster prey AU - Eggleston, DB AU - Lipcius, RN AU - Grover, JJ 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 149:43-59 (1997) - doi:10.3354/meps149043 Predator and shelter-size effects on coral reef fish and spiny lobster prey Eggleston DB, Lipcius RN, Grover JJ Population dynamics of coral reef fishes and spiny lobster appear to be determined by variable recruitment interacting with post-settlement processes, particularly predation. The risk of predation may be modified by the scaling between prey and shelter size, which enhances the protective capacity of a reef. We experimentally tested these predictions by manipulating densities of predatory Nassau grouper Epinephelus striatus on 8 artificial patch reefs of 2 sizes (small, large) in a large seagrass bed near Lee Stocking Island, Bahamas. We initially censused patch reefs for 7 mo, after which we randomly selected equivalent numbers of small and large reefs to serve as permanent grouper removal versus control (non-removal) reefs. We continued to census patch reefs for 12 mo after predators were removed from certain reefs. The abundance of predatory Nassau grouper and the size of shelters from predation jointly explained the observed distribution and abundance patterns of spiny lobster and reef fish prey inhabiting artificial patch reef habitats. For example, the abundance of small lobsters was highest in small reefs where Nassau grouper were experimentally removed. When we assessed the effects of predator abundance on all reef fish prey (1 to 10 cm TL), we were unable to detect any significant effects on prey abundance or species diversity due to low statistical power. However, the total abundance and species richness of medium size reef fish (4 to 10 cm TL) was significantly higher in small shelters from which grouper were removed. In comparing species' relative abundances on reefs with low versus high numbers and Nassau grouper, the results indicated that grouper reduce prey abundances in a generalized, non-selective pattern, with no difference in the number of rare versus common prey species that were extirpated. Thus, juvenile Nassau grouper inhabiting certain patch reefs produce a general predatory impact, whereby predation reduces prey abundance and diversity in proportion to the initial relative abundance of prey. Our results support the prediction that at certain scales of space and time, post-settlement predation is a critical determinant of population abundance and species diversity of reef-fish and spiny lobster prey, and that the effect of predation is mediated by the protective capacity of a reef. Coral-reef fishes · Predation · Recruitment · Shelter scaling · Spiny lobster Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 149. Publication date: April 10, 1997 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1997 Inter-Research. DA - 1997/4// PY - 1997/4// DO - 10.3354/meps149043 VL - 149 IS - 1-3 SP - 43-59 SN - 0171-8630 KW - coral-reef fishes KW - predation KW - recruitment KW - shelter scaling KW - spiny lobster ER - TY - JOUR TI - On the measurements of cloud condensation nuclei at Palmer Station, Antarctica AU - Defelice, TP AU - Saxena, VK AU - Yu, SC T2 - ATMOSPHERIC ENVIRONMENT AB - This article presents and discusses the predominant characteristics associated with a first dataset of daily daylight period (i.e. ≃13-15 h long) averaged cloud condensation nuclei spectral measurements at a remote region of the globe, namely Palmer Station, Antartica. DA - 1997/12// PY - 1997/12// DO - 10.1016/S1352-2310(97)00250-1 VL - 31 IS - 23 SP - 4039-4044 SN - 1352-2310 KW - cloud condensation nuclei (CCN) KW - Antarctic region KW - meteorology and CCN ER - TY - JOUR TI - A linear theory for jet streak formation due to zonal momentum forcing in a stably stratified atmosphere AU - Weglarz, RP AU - Lin, YL T2 - JOURNAL OF THE ATMOSPHERIC SCIENCES AB - A perturbation potential vorticity (PV) theory is developed to investigate the three-dimensional, time-dependent, linear geostrophic adjustment of a stably stratified, Boussinesq atmosphere that is disturbed from (i) quiescent equilibrium due to a localized, unbalanced, zonal wind anomaly and (ii) geostrophic equilibrium of the uniform zonal flow due to an isolated couplet of acceleration–deceleration forcing. This prescribed zonal momentum forcing propagates downstream at a speed c that is less than the basic-state zonal flow speed U and physically represents the parameterized effects of nonlinear inertial advection. Transient, dispersive inertia–gravity waves in all fields are essentially removed during the early stage of the response associated with the initial value problem. The steady-state equilibrium that conserves the initial perturbation PV is a localized, geostrophic zonal jet with meridionally confluent (diffluent) flow in its entrance (exit) region. This jet is supported by a couplet of perturbation low and high pressure north and south of the zonal jet core, respectively. There exist no steady-state ageostrophic winds and vertical motions once balanced equilibrium is reached. This long-term asymptotic response characterizes a localized linear thermal wind balance among the baroclinic perturbations that will not be preserved in the nonlinear initial value problem. The forced response for a uniform, stably stratified, zonal flow whose Rossby number is RoU = (U − c)/2af = 0.1, where a is the half-width of the prescribed zonal momentum forcing as seen by a Galilean observer traveling at the speed c < U, shows many similar characteristics with the forced shallow water flow response of Weglarz. In particular, the early response for t ≤ τ = 2a/(U − c) is characterized by a pair of easterly and westerly zonal jet streaks produced by flow acceleration/deceleration in the forcing entrance/exit region. The mass field quickly adjusts to the sub-Rossby scale (a ≪ 2djetN/f) perturbations in the wind field, forming a pair of high–low couplets that geostrophically support the isolated zonal jets. For t > τ, the easterly zonal jet is advected downstream at the relative velocity U − c, leaving an isolated, meso-α-scale, westerly zonal jet streak in the vicinity of the forcing center. The ageostrophic winds characterize a mesoscale cyclonic circulation that circumvents the forcing center. The divergence associated with this circulation produces a four-cell pattern of vertical motion that flanks the core of the zonal jet streak. This pattern of steady, externally forced, vertical motion is reversed from the pattern normally inferred from traditional nonlinear quasigeostrophic jet streak dynamics because the accelerations produced by the imposed zonal momentum forcing dominate those produced by local time rate of change and linear inertial advection of the geostrophic flow. DA - 1997/4/1/ PY - 1997/4/1/ DO - 10.1175/1520-0469(1997)054<0908:ALTFJS>2.0.CO;2 VL - 54 IS - 7 SP - 908-932 SN - 0022-4928 ER -