TY - JOUR TI - A Canal Drawdown Experiment for Determination of Aquifer Parameters AU - Genereux, David AU - Guardiario, Jose T2 - Journal of Hydrologic Engineering AB - A canal drawdown experiment was used in conjunction with borehole flowmeter measurements to determine the following hydrologic parameters: (1) the transmissivity (T) and hydraulic conductivity (K) of the Biscayne Aquifer in southeast Florida; (2) the separate hydraulic conductivities of the Miami Limestone (KM) and the Fort Thompson Formation (KF)–the two geologic formations making up the Biscayne Aquifer; and (3) the conductance (C) controlling water seepage between the Biscayne Aquifer and the L-31W borrow canal (the canal in which the drawdown experiment was carried out). While the canal drawdown experiment alone would have yielded T and K, also making borehole flowmeter and aquifer thickness measurements allowed determination of KM and KF. Two methods of data analysis were used; one based on the Dupuit equation, the other on a previously published set of equations developed specifically for computing the C value required for a regional numerical ground-water flow model. The two methods were in good agreement (within 20% of each other), and averaging results from them gave T= 1.0 × 105 m2/day, K= 7,590 m/day, KM= 14,900 m/day, and KF= 4,050 m/day. Estimates of C from the two methods were also similar, although the exact value derived from the second method would necessarily depend on the size of the model grid cell for which the value was calculated. The methods applied here illustrate an effective means for measurement of field-scale hydrologic parameters and confirm the importance of canal sediments in controlling ground-water exchange with the L-31W canal on the eastern boundary of Everglades National Park. DA - 1998/10// PY - 1998/10// DO - 10.1061/(ASCE)1084-0699(1998)3:4(294) VL - 3 IS - 4 SP - 294-302 J2 - J. Hydrol. Eng. LA - en OP - SN - 1084-0699 1943-5584 UR - http://dx.doi.org/10.1061/(ASCE)1084-0699(1998)3:4(294) DB - Crossref ER - TY - JOUR TI - Quantifying uncertainty in tracer‐based hydrograph separations AU - Genereux, David T2 - Water Resources Research AB - A method is presented for quantifying the uncertainty in two‐ and three‐component tracer‐based hydrograph separations. The method relates the uncertainty in computed mixing fractions to both the tracer concentrations used to perform the hydrograph separation and the uncertainties in those concentrations. A two‐component example and a three‐component example illustrate the application of the method. The three‐component example yields uncertainty results very similar to those from a previously published Monte Carlo analysis and requires less computation. DA - 1998/4// PY - 1998/4// DO - 10.1029/98WR00010 VL - 34 IS - 4 SP - 915-919 J2 - Water Resources Research LA - en OP - SN - 0043-1397 1944-7973 UR - http://dx.doi.org/10.1029/98WR00010 DB - Crossref ER - TY - CHAP TI - Applications of Uranium- and Thorium-Series Radionuclides in Catchment Hydrology Studies AU - Kraemer, Thomas F. AU - Genereux, David P. T2 - Isotope Tracers in Catchment Hydrology AB - This chapter discusses applications of uranium- and thorium-series radionuclides in catchment hydrology studies. It also reviews the environmental behavior of the various radionuclides in order to understand and predict their presence and transport in the environment as a result of mining, milling, and other technological redistributions of ores and other materials naturally high in radionuclides. Uranium and thorium decay products are used to determine the age of speleothems and archeological remains, sedimentation rates of marine and lake sediments, rates of water-rock re-equilibration in hydrothermal systems, and calculation of erosion rates on a continental scale. The approaches and models used in interpreting uranium- and thorium-series radionuclide data are simpler and less sophisticated than those that have been developed for stable isotope. Uranium and thorium are long-lived radioactive elements found in all earth material. Uranium can also be removed from solution, even oxidizing ones, by adsorption onto solid substrates due to changing pH. Adsorption of uranium onto ferric oxyhydroxides, clay minerals, and even micaceous minerals at pH values common in natural waters is well known. The application of uranium- and thorium-series radionuclides to quantitatively solve problems in small catchment hydrologic studies has been largely neglected. PY - 1998/// DO - 10.1016/B978-0-444-81546-0.50027-6 SP - 679-722 PB - Elsevier UR - http://dx.doi.org/10.1016/B978-0-444-81546-0.50027-6 ER - TY - CHAP TI - Oxygen and Hydrogen Isotopes in Rainfall-Runoff Studies AU - Genereux, David P. AU - Hooper, Richard P. T2 - Isotope Tracers in Catchment Hydrology AB - This chapter provides an overview of traditional hydrograph separation applications on storm event time-scales, and discusses the requirements for successful separation and the results of several isotopic hydrograph separation studies. It also presents other frameworks for application of isotope data on storm-event and longer time-scales, and the findings from a number of studies in which oxygen and/or hydrogen isotopes were used to separate storm streamflow into pre-event and event water. Stable isotopes of oxygen and hydrogen have proven to be useful tools in determining the contribution of rainfall to stormflow, the residence time of water on catchments, and other aspects of watershed hydrology. The separation of contributions from event and pre-event waters to stormflow adds a constraint on streamflow generation that physical (hydrometric) measurements never could. The large contribution of pre-event water to storm streamflow is entirely consistent with the importance of subsurface stormflow as documented by hydrometric studies on forested catchments before isotopes became widely used. Pre-event water usually makes up the bulk of stormflow through some combination of mixing and displacement, even discharging to streams through macro-pores and soil pipes. The isotopes move as the water moves and do not fractionate between the time the water reaches the ground and the time the water exits the catchment as streamflow. PY - 1998/// DO - 10.1016/B978-0-444-81546-0.50017-3 SP - 319-346 PB - Elsevier UR - http://dx.doi.org/10.1016/B978-0-444-81546-0.50017-3 ER - TY - JOUR TI - Two-dimensional turbulence and persistent zonal jets in a global barotropic model AU - Huang, H.-P. AU - Robinson, W.A. T2 - Journal of the Atmospheric Sciences AB - The dynamics of two-dimensional turbulence on a rotating sphere are examined. The anisotropic Rhines scale is derived and verified in decaying turbulence simulations. Due to the anisotropic nature of the Rossby waves, the Rhines barrier is displaced toward small total wavenumber n with decreasing zonal wavenumber m. Up-scale energy transfer along the zonal axis (m = 0) is not directly arrested by beta. A forced dissipative model with high-wavenumber forcing is used to investigate the dynamics of persistent zonal jets. Persistent jets form in the low energy (strong rotation) cases with the root-mean-square velocity V*rms ≪ aΩ. Under a fixed rotation rate, the jet scale decreases with the energy. The equilibrated jets generally stay at fixed latitudes. The zonal bands are nearly uniformly distributed in latitude, except that bands in the high latitudes tend to be wider and weaker, as clearly affected by a decreasing beta with latitude. The time-mean zonal winds in the forced simulations appear to be stable, with their absolute vorticity gradient dominated by beta. The increase of the jet scale with energy as required by stability is consistent with the simulated results. Diagnostic analysis shows that the persistent jets are primarily maintained by the shear-straining mechanism involving small-scale eddies and large-scale zonal jets, with a clear scale separation between them. Although large-scale eddies, those at scales near the Rhines scale, possess most of the eddy energy, in the time mean they contribute little to the maintenance of the zonal jets. Thus, despite the similarity between the Rhines scale and the jet scale, their dynamical link is not obvious in the time-mean statistics. The presence of persistent zonal jets modifies the normal modes of the system. Pure Rossby–Haurwitz modes at small and medium scales are severely modified and fall into the continuum. Large-scale modes, however, may remain discrete. The discreteness of the large-scale modes limits their ability to exchange energy with the zonal jets in the time mean. DA - 1998/// PY - 1998/// DO - 10.1175/1520-0469(1998)055<0611:TDTAPZ>2.0.CO;2 VL - 55 IS - 4 SP - 611-632 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0031860282&partnerID=MN8TOARS ER - TY - JOUR TI - Health care reform and public health: A paper on population-based core functions: The core functions project, U.S. public health service, 1993 AU - Lee, P.R. AU - Elders, M.J. AU - McGinnis, J.M. AU - Satcher, D. AU - Clinton, J.J. AU - Kessler, D.A. AU - Robinson, W.A. AU - Lincoln, M.E. AU - Varmus, H. AU - Johnson, E.M. AU - Feingold, E. AU - Ibrahim, M. AU - Mahan, C.S. AU - Mullet, M.E. AU - Mecca, A. AU - Schafer, K. AU - Olivas, G. T2 - Journal of Public Health Policy DA - 1998/// PY - 1998/// DO - 10.2307/3343074 VL - 19 IS - 4 SP - 394-419 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0032425351&partnerID=MN8TOARS ER - TY - JOUR TI - HRDI observations of mean meridional winds at solstice AU - Lieberman, RS AU - Robinson, WA AU - Franke, SJ AU - Vincent, RA AU - Isler, , JR AU - Fritts, DC AU - Manson, AH AU - Meek, CE AU - Fraser, GJ AU - Fahrutdinova, A AU - Hocking, W AU - Thayaparan, T AU - MacDougall, J AU - Igarashi, K AU - Nakamura, T AU - Tsuda, T T2 - Journal of the Atmospheric Sciences AB - High Resolution Doppler Imager (HRDI) measurements of daytime and nighttime winds at 95 km are used to deduce seasonally averaged Eulerian mean meridional winds during six solstice periods. These estimates are compared with seasonally averaged radar meridional winds and with results from dynamical and empirical wind models. HRDI mean meridional winds are directed from the summer pole toward the winter pole over much of the globe. Peak equatorward winds of about 15 m s−1 are usually observed in the summer hemisphere near 30°. A local minimum in the equatorward winds is often observed poleward of this latitude, with winds approaching zero or reversing direction. A similar structure is seen in contemporaneous radar winds. This behavior differs from residual meridional wind patterns predicted by models. The discrepancies may be related to gravity wave paramaterizations or a consequence of planetary wave influences. DA - 1998/// PY - 1998/// DO - 10.1175/1520-0469(1998)055<1887:HOOMMW>2.0.CO;2 VL - 55 IS - 10 SP - 1887-1896 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000073667500010&KeyUID=WOS:000073667500010 ER - TY - CONF TI - Characterization of nitric oxide emissions from an intensively managed agricultural soil in North Carolina, U.S.A. AU - Roelle, P. AU - O’Connor, J. AU - Robarge, W. AU - Aneja, V.P. C2 - 1998/// C3 - International Conference on Air Pollution - Proceedings DA - 1998/// SP - 607-616 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0032312190&partnerID=MN8TOARS ER - TY - CONF TI - Biogenic nitric oxide source strength in the southeast United States AU - Aneja, Viney P. AU - Roelle, Paul A. AU - O’Connor, James R. AU - Robarge, Wayne P. C2 - 1998/// C3 - Proceedings of the Air & Waste Management Association's Annual Meeting & Exhibition DA - 1998/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0032256837&partnerID=MN8TOARS ER - TY - JOUR TI - Atmospheric nitrogen compounds: Emissions, transport, transformation, deposition, and assessment AU - Aneja, V.P. AU - Murray, G.C. AU - Southerland, J. T2 - EM: Air and Waste Management Association's Magazine for Environmental Managers DA - 1998/// PY - 1998/// IS - 4 SP - 22-25 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0032045968&partnerID=MN8TOARS ER - TY - CONF TI - Shewhart Charting Applied to the Growth of Pig Populations AU - Roberts, J. AU - Deen, J. AU - Levine, J.F. AU - Almond, G.W. T2 - International Pig Veterinary Society C2 - 1998/// DA - 1998/// PY - 1998/// ER - TY - JOUR TI - Multi-scale Green's function Monte Carlo approach to erosion modelling and its application to land-use optimization AU - Mitas, L. AU - Mitasova, H. T2 - IAHS-AISH Publication DA - 1998/// PY - 1998/// VL - 249 SP - 81-90 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-3342913036&partnerID=MN8TOARS ER - TY - BOOK TI - Multi-scale Green's function Monte Carlo approach to erosion modelling and its application to land-use optimization AU - Mitas, L. AU - Mitasova, H. DA - 1998/// PY - 1998/// SE - 81-90 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0031767430&partnerID=MN8TOARS ER - TY - JOUR TI - Distributed soil erosion simulation for effective erosion prevention AU - Mitas, L. AU - Mitasova, H. T2 - Water Resources Research DA - 1998/// PY - 1998/// VL - 34 IS - 3 SP - 505-516 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0031911252&partnerID=MN8TOARS ER - TY - RPRT TI - Post Kyoto strategies: the CDM, international cooperation and private sector participation AU - Kaplan, M. AU - Cuciti, P. AU - Steelman, T. A. A3 - Denver: Institute for Policy Implementation, Graduate School of Public Affairs, University of Colorado at Denver DA - 1998/// PY - 1998/// PB - Denver: Institute for Policy Implementation, Graduate School of Public Affairs, University of Colorado at Denver ER - TY - MAP TI - Geology of the Ojito Springs 7.5-minute quadrangle, Sandoval county, New Mexico AU - Formento-Trigilio, M. L. AU - Wegmann, K. AU - Pazzaglia, F. J. DA - 1998/// PY - 1998/// PB - New Mexico Bureau of Mines and Mineral Resources ER - TY - RPRT TI - Geology and geomorphology at archeological sites along New Mexico Highway 44 [contract report] AU - Wegmann, K. W. AU - Pederson, J. L. A3 - University of New Mexico, Office of Contract Archeology DA - 1998/// PY - 1998/// PB - University of New Mexico, Office of Contract Archeology ER - TY - JOUR TI - Greendays: An environmental almanac AU - McConnell, D. A. T2 - Journal of Geoscience Education DA - 1998/// PY - 1998/// VL - 46 SP - 211+ ER - TY - JOUR TI - Tropospheric ozone production and transport in the springtime in east Asia AU - Carmichael, GR AU - Uno, I AU - Phadnis, MJ AU - Zhang, Y AU - Sunwoo, Y T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Ozone transport and chemistry in the springtime in east Asia are studied by use of the STEM‐II (Sulfur Transport Eulerian Model) regional‐scale transport/chemistry model. Three‐dimensional simulations are performed for the period May 1–15, 1987. This was a period of strong downward transport of ozone in east Asia, associated with traveling low‐pressure systems. Elevated ozone levels were observed at high‐altitude surface sites in Japan during this period. Model simulations both with and without photochemical processes are performed in order to assess the relative importance of the transport and chemical sources of tropospheric ozone. The model results are compared with measured values at a network of stations in Japan and are found to accurately capture most of the important observed features. Near‐surface ozone levels are found to be strongly influenced both by continental outflow of precursors occurring behind the cold fronts as they move out over the Pacific Ocean and by the strong downward transport of ozone‐rich air from the upper troposphere which occurs in association with these weather systems. DA - 1998/5/20/ PY - 1998/5/20/ DO - 10.1029/97JD03740 VL - 103 IS - D9 SP - 10649-10671 SN - 2169-8996 ER - TY - JOUR TI - Sensitivity analysis of a mixed-phase chemical mechanism using automatic differentiation AU - Zhang, Y AU - Bischof, CH AU - Easter, RC AU - Wu, PT T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - A sensitivity analysis of a comprehensive mixed‐phase chemical mechanism is conducted under a variety of atmospheric conditions. The local sensitivities of gas and aqueous phase species concentrations with respect to a variety of model parameters are calculated using the novel automatic differentiation ADIFOR tool. The main chemical reaction pathways in all phases, interfacial mass transfer processes, and ambient physical parameters that affect tropospheric O 3 formation and O 3 ‐precursor relations under all modeled conditions are identified and analyzed. The results show that the presence of clouds not only reduces many gas phase species concentrations and the total oxidizing capacity but alters O 3 ‐precursor relations. Decreases in gas phase concentrations and photochemical formation rates of O 3 can be up to 9% and 100%, respectively, depending on the preexisting atmospheric conditions. The decrease in O 3 formation is primarily caused by the aqueous phase reactions of O 2 − with dissolved HO 2 and O 3 under most cloudy conditions. DA - 1998/8/20/ PY - 1998/8/20/ DO - 10.1029/98jd01278 VL - 103 IS - D15 SP - 18953-18979 SN - 2169-897X ER - TY - JOUR TI - Modeling studies for the effects of spring-time mineral aerosols on the transport and deposition of sulfur in East Asia using the STEM-II model AU - Xiao, H. AU - Carmichael, G. R. AU - Zhang, Y. T2 - Climatic and Environmental Research (Chinese) DA - 1998/// PY - 1998/// VL - 3 IS - 2 SP - 106-116 ER - TY - JOUR TI - A modeling evaluation of the impact of mineral aerosol on the particulate sulfate formation in East Asia AU - Xiao, H. AU - Carmichael, G. R. AU - Zhang, Y. T2 - Chinese Journal of Atmospheric Sciences = Da Qi Ke Xue = Scientia Atmospherica Sinica DA - 1998/// PY - 1998/// VL - 22 IS - 3 SP - 343-353 ER - TY - JOUR TI - Mesoscale dynamics in the Palm Sunday tornado outbreak AU - Koch, SE AU - Hamilton, D AU - Kramer, D AU - Langmaid, A T2 - MONTHLY WEATHER REVIEW AB - Radar and satellite imagery suggest that strong mesoscale forcing occurred in the Palm Sunday tornado outbreak on 27 March 1994. Parallel lines of severe thunderstorms within each of three mesoscale convective systems developed just ahead of a cold front in Mississippi and Alabama on this date. Analyses of routine meteorological observations, barograph data, and forecasts from the Eta and NGM models and a mesoscale research model (MASS) are used to examine the relative roles of large-scale dynamics and mesoscale processes in triggering and organizing the mesoscale convection. Quasigeostrophic forcing was absent in the outbreak region. Likewise, a thermally direct circulation system transverse to the upper-level jet that was present to the northwest of the outbreak region was decoupled from the strong low-level ascent occurring in northern Alabama and Mississippi at the time of the outbreak. Strong ageostrophic frontogenesis in the presence of conditional symmetric instability (CSI) was the chief cause for the intense low-level ascent along and behind the front, consistent with the line of severe storms that developed explosively along the front and an observed postfrontal precipitation band. However, the strongest supercells developed in segmented lines 100–200 km ahead of and parallel to the frontal boundary in an atmosphere that the MASS model indicates was inertially unstable due to a mesoscale midlevel jetlet. Analysis suggests that these storms developed in a manner consistent with the predictions of asymmetric inertial instability theory in the presence of convective instability. Several mesolows were observed to have traveled along the frontal boundary and to have played a key role in focusing the frontogenesis. Similar frontal mesolows were simulated by the MASS model. Strong low-level ascent in the presence of conditional instability helped to deepen the mesolows, but they were strongly modulated by a train of gravity waves propagating on the cold side of the front. A combination of ducting and wave-CISK (conditional instability of the second kind) processes maintained the waves, which remained coupled to the jetlets as they propagated from intense convection in northeastern Texas. A time-to-space conversion objective analysis of bandpass-filtered barograph data reveals that similar waves emanated from this same region. The lifting patterns produced by the complex interactions between the gravity waves, CSI, asymmetric inertial instability, and frontogenesis satisfactorily explains the development, configuration, spacing, and relative movement of the severe mesoconvective systems on Palm Sunday. All of these mesoscale phenomena were coupled to or strongly influenced by the jetlets, which were produced by strong convection at an earlier time within the region of quasigeostrophic forcing far removed from the tornado outbreak. DA - 1998/8// PY - 1998/8// DO - 10.1175/1520-0493(1998)126<2031:MDITPS>2.0.CO;2 VL - 126 IS - 8 SP - 2031-2060 SN - 1520-0493 ER - TY - CONF TI - A comparison of how different orientation behaviors influence dinoflagellate trajectories and photoresponses in turbulent water columns AU - Kamykowski, D. AU - Yamazaki, H. AU - Yamazaki, A. K. AU - Kirkpatrick, G. J. A2 - D. M. Anderson, A. D. Cembella A2 - Hallegraeff, G. M. C2 - 1998/// C3 - Physiological ecology of harmful algal blooms (NATO ASI series. Series G, Ecological sciences ; no. 41) CN - QK568.T67 P48 1998 DA - 1998/// SP - 581-599 PB - Berlin ; New York: Springer ER - TY - CONF TI - Isotope paleobiology of the vertebrates: ecology, physiology, and diagenesis AU - Barrick, R. E. A2 - R. M. Feldmann, R. E. Chapman A2 - Hannibal, J. T. C2 - 1998/// C3 - Paleotechniques (Special publication (Paleontological Society) ; no. 4) DA - 1998/// SP - 101-137 PB - Knoxville, TN: Dept. of Geologial Sciences, University of Tennessee ER - TY - BOOK TI - Dynamics of atmospheric flows: Atmospheric transport and diffusion processes AU - Singh, M. P. AU - Raman, S. CN - QC880.4.D44 D96 1998 DA - 1998/// PY - 1998/// PB - Boston, MA: Computational Mechanics Publications SN - 1853124273 ER - TY - JOUR TI - The habitat-survival function for Caribbean spiny lobster: an inverted size effect and non-linearity in mixed algal and seagrass habitats AU - Lipcius, RN AU - Eggleston, DB AU - Miller, DL AU - Luhrs, TC T2 - MARINE AND FRESHWATER RESEARCH AB - The habitat-survival function (HSF) defines changes in survival relative to habitat structure; forms include linear, hyperbolic and sigmoid (threshold) curves, whose consequences on predator–prey dynamics are illustrated by their first derivatives. Survival of two juvenile size classes of Caribbean spiny lobster was evaluated as a function of plant biomass in tethering experiments in mixed algal and seagrass patches adjacent to Bahía de la Ascensión, Mexico, which serves as nursery habitat. The HSF was hyperbolic for algal biomass; even modest increases of algal biomass significantly enhanced lobster survival. The rate of change in survival as a function of algal biomass (i.e. an approximation of the first derivative) was greatest at low-to-moderate levels of habitat structure. Hence, survival in these microhabitats is either low or rapidly changing with alterations in habitat structure, and they should be avoided by juveniles. Seagrass biomass did not significantly influence survival, although its levels were relatively low. Smaller juveniles had significantly higher survival rates than larger juveniles, probably because of the limited availability of appropriately scaled refugia for larger juveniles; large juveniles may display an ontogenetic shift from these habitats to coral reefs because of elevated predation risk as they grow. DA - 1998/// PY - 1998/// DO - 10.1071/MF97094 VL - 49 IS - 8 SP - 807-816 SN - 1448-6059 ER - TY - CONF TI - Ribosomal DNA from the toxic dinoflagellate pfiesteria piscicida AU - Toffer, K. L. AU - Schaefer, E. F. AU - Glasgow, H. B. AU - Burkholder, J. M. AU - Rublee, P. A. C2 - 1998/// C3 - Harmful algae = Algas nocivas: Proceedings of the VIII International Conference on Harmful Algae, Vigo, Spain, 25-29 June 1997 CN - QK568.T67 I58 1997 DA - 1998/// SP - 278-279 PB - Vigo, Spain: Intergovernmental Oceanographic Commission of Unesco ER - TY - CHAP TI - Physiological ecology of Pfiesteria piscicida with general comments on 'ambush-oredator' dinoflagellates AU - Burkholder, J. M. AU - Glasgow, H. B. AU - Lewitus, A. J. T2 - Physiological ecology of harmful algal blooms A2 - D. M. Anderson, A. D. Cembella A2 - Hallegraeff, G. M. CN - QK568.T67 P48 1998 PY - 1998/// VL - 41 SP - 175-191 PB - New York: Springer ER - TY - JOUR TI - Influence of sediment and phosphorus loading on phytoplankton communities in an urban piedmont reservoir AU - Burkholder, J. M. AU - Larser, L. M. AU - Glasgow, H. B. AU - Mason, K. M. AU - Gama, P. AU - Parsons, J. E. T2 - Lake and Reservoir Management AB - ABSTRACT The response of phytoplankton communities to an imposed gradient of sediment loading under low versus high phosphate enrichment was assessed with enclosures (2-m-diameter polyethylene columns, open to the surface and the sediment) in a small piedmont reservoir within an urbanized watershed. The experimental design included replicated controls [CON, with ambient suspended solids (SS) and phosphorus (P)] and treatments low clay (LC), a natural hydrated sediment mix, sufficient clay initially added to effect an average daily concentration of 5 mg SS L−1 d−1), high clay (HC), 15 mg SS·L−1·d−1, phosphate enrichment (PHOS), ≥ 250 μg PO4 −3 P L−1); LC+P, and HC+P, imposed for ca. 10 weeks in the summer growing season. Clay additions without P led to decreased phytoplankton production (as chlorophyll a, chla) relative to controls, with colonial blue-greens and colonial greens increasing in LC, and HC dominated by filamentous blue-greens and mixotrophic flagellates. Significant increases in chla occurred in the epilimnion and hypolimnion of the P treatment, and in the epilimnion of LC+P, and HC+P. Low variability in community response occurred in treatments with sediment loading alone, whereas the P additions imposed high variability among replicates within treatments considering both total algal production and the timing of blooms. Overall, P enrichment stimulated nuisance algal blooms whether alone or with low sediment inputs, and increased P mitigated the adverse effects of high sediment loading in supporting blue-green (cyanobacteria) blooms. Undesirable algae such as Anabaena flos-aquae and A. circinalis were able to maintain populations under high sediment loading, and may serve as an innoculum for development of noxious blooms when shallow, turbid systems experienced high P enrichment. DA - 1998/// PY - 1998/// DO - 10.1080/07438149809354114 VL - 14 IS - 1 SP - 110-121 ER - TY - CONF TI - Feeding behavior of the icthyotoxic estuarine dinoflagelate pfiesteria piscicida on amino acids, algal prey, and fish vs. mammalian erythrocytes AU - Glasgow, H. B. AU - Lewitus, A. J. AU - Burkholder, J. M. C2 - 1998/// C3 - Harmful algae = Algas nocivas: Proceedings of the VIII International Conference on Harmful Algae, Vigo, Spain, 25-29 June 1997 CN - QK568.T67 I58 1997 DA - 1998/// SP - 394-397 PB - Vigo, Spain: Intergovernmental Oceanographic Commission of Unesco ER - TY - CHAP TI - Unstable and convective boundary layers AU - Arya, S. P. T2 - Dynamics of atmospheric flows: Atmospheric transport and diffusion processes A2 - M. P. Singh, A2 - Raman, S. CN - QC880.4.D44 D96 1998 PY - 1998/// SP - 1-38 PB - Boston: Computational Mechanics Publications SN - 1853124273 ER - TY - JOUR TI - The use of pre-storm boundary-layer baroclinicity in determining and operationally implementing the Atlantic surface cyclone intensification index AU - Cione, JJ AU - Neuherz, RA AU - Raman, S AU - Pietrafesa, LJ AU - Keeter, K AU - Li, XF T2 - BOUNDARY-LAYER METEOROLOGY DA - 1998/11// PY - 1998/11// DO - 10.1023/A:1001773019199 VL - 89 IS - 2 SP - 211-224 SN - 0006-8314 KW - cyclogenesis KW - rapid deepening KW - Gulf Stream KW - baroclinicity KW - cold air advection ER - TY - CHAP TI - Regional and temporal models for ozone along the Gulf Coast AU - Davis, J. M. AU - Eder, B. K. AU - Bloomfield, P. T2 - Case studies in environmental statistics A2 - D. Nychka, W. W. Piegorsch A2 - Cox, L. H. AB - The studies described in the previous chapter focused on estimating trends in a daily ozone summary having adjusted for the relationship of surface ozone concentrations to meteorology. Moreover, the analysis was largely restricted to the Chicago urban area. This chapter contrasts this narrow scope by studies that: CN - GE45.S73 C38 1998 PY - 1998/// DO - 10.1007/978-1-4612-2226-2_3 SP - 27-50 PB - New York: Springer ER - TY - JOUR TI - Nonlinear adjustment of a rotating homogeneous atmosphere to zonal momentum forcing AU - Weglarz, RP AU - Lin, YL T2 - TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY DA - 1998/10// PY - 1998/10// DO - 10.1034/j.1600-0870.1998.t01-4-00004.x VL - 50 IS - 5 SP - 616-636 SN - 0280-6495 ER - TY - CHAP TI - Modeling ozone in the Chicago urban areas AU - Davis, J. M. AU - Eder, B. K. AU - Bloomfield, P. T2 - Case studies in environmental statistics A2 - D. Nychka, W. W. Piegorsch A2 - Cox, L. H. AB - Ozone (O3) is a ubiquitous trace gas in the atmosphere. Its highest concentration is in the stratosphere, where it shields the earth’s surface from harmful ultraviolet radiation. At the surface, however, ozone is itself harmful, with destructive impacts on materials, crops, and health. Its levels have been high enough in certain areas to be of concern for several decades. CN - GE45.S73 C38 1998 PY - 1998/// DO - 10.1007/978-1-4612-2226-2_2 SP - 5-26 PB - New York: Springer ER - TY - JOUR TI - Eddy maintenance and attrition in a vertically sheared current under Arctic ice AU - Chao, SY AU - Shaw, PT T2 - JOURNAL OF PHYSICAL OCEANOGRAPHY AB - Steady drift of an ice cover produces a vertically sheared current in the upper ocean of the Arctic. Under the ice cover, mesoscale shallow brine and freshening sources generate submerged anticyclones and cyclones, respectively. A submerged eddy extending deep into the water column experiences differential advections by the vertically sheared current. Interaction between subsurface eddies and the sheared current is examined using a three-dimensional numerical model in a coordinate system moving with the ice. The initial salinity field is in geostrophic balance with the sheared current, and a pulse of brine or freshening forcing produces an anticyclone or a cyclone. In a coordinate system moving with the ice, eddies are in a vertically sheared backward ambient current. To an observer looking into the direction of the backward ambient current, eddies move with the current and deflect to the right (left) for counterclockwise (clockwise) rotating eddies in both hemispheres. The lower half of the eddy always moves faster. The lateral movement can be explained by the Kutta–Zhukhovski lift theorem. Differential advection produces eddy tilting and entails the development of a narrow jet following the moving eddy. The jet reduces eddy straining and tilting, and eddies disperse in cases of sizeable tilts. Driven by a vertically sheared current, cyclones are short-lived compared with anticyclones because the lateral movement of a cyclone exposes the lower part of the eddy into waters of weaker stratification. The results help explain the predominance of anticyclonic eddies under the Arctic ice. DA - 1998/12// PY - 1998/12// DO - 10.1175/1520-0485(1998)028<2427:EMAAIA>2.0.CO;2 VL - 28 IS - 12 SP - 2427-2443 SN - 0022-3670 ER - TY - JOUR TI - Dinosaur skin impressions and associated skeletal remains from the upper Campanian of southwestern New Mexico: New data on the integument morphology of hadrosaurs AU - Anderson, BG AU - Lucas, SG AU - Barrick, RE AU - Heckert, AB AU - Basabilvazo, GT T2 - JOURNAL OF VERTEBRATE PALEONTOLOGY AB - ABSTRACT Skin impressions from the tail region of an indeterminate hadrosaur recently excavated from the Upper Cretaceous Ringbone Formation, southwest New Mexico represent the first known dinosaur specimen from New Mexico with impressions of the integument preserved in association with skeletal remains. The mid- to distal-caudal region is represented by 20 articulated centra, other disarticulated centra, a single chevron, ossified tendons and fragmentary bone, including poorly preserved neural spines. The skin impressions are preserved in negative and positive relief between two very fine-grained sandstone beds, interpreted as part of a fluvio-lacustrine facies package. The impression surface is directly below the ossified tendons, and 2.5 m from the articulated vertebral column. The skin impressions are six discrete patches characterized by predominantly apical, circular to ovate tubercles. Measurements of the long and short axes of individual tubercles demonstrate that a distribution of relatively homogenous tubercle sizes occur along the tail section. The tubercles range from 3 to 12 mm and 10 to 16 mm on the short and long axes, respectively. All tubercles examined are ornamented with radiating ridges and grooves that converge at their apex. Presently, the material cannot be identified below the level of Hadrosauridae; however, a comparison of tubercle size, shape and ornamentation described previously from hadrosaur skin impressions indicates the integument morphology of the Ringbone hadrosaur has some similarities to that of the gryposaurs. In general, the complexity of the radial sculpturing, specifically the number of ridges and rugosity, increases with increasing tubercle size. This specific type of ornamentation is not known from modern reptiles or birds; however, the tubercular morphology is similar to that of the lizard Heloderma. Although it is impossible to determine whether the ridges and grooves may have had a physiologic function, these features would increase the surface area of the skin, and therefore may have afforded more efficient heat exchange across the skin, or possibly provided added resistance to tearing and puncturing. DA - 1998/12// PY - 1998/12// DO - 10.1080/02724634.1998.10011102 VL - 18 IS - 4 SP - 739-745 SN - 0272-4634 ER - TY - JOUR TI - Characterization of biogenic nitric oxide source strength in the southeast United States AU - Aneja, VP AU - Roelle, PA AU - Robarge, WP T2 - ENVIRONMENTAL POLLUTION AB - Emissions of nitric oxide (NO) were measured during the summer of 1995 from 4 crops, located at three different sites throughout North Carolina. These sites were chosen to represent major physiographic regions of the Southeast US, in an effort to compare fluxes from different agriculturally managed soils. Emission rates were determined using a dynamic flow-through chamber system. In order to understand the NO flux from the different soil and crop types, measurements were made on corn and soybean crops in the coastal region, tobacco in the Piedmont region, and corn in the upper Piedmont region of North Carolina. Average NO fluxes were 5.5 f 2.2 ng N me2 s-‘, 20.7 + 19.2 ng N me2 s-‘, 4.1 + 1.4 ng N m-2s-1, and 8.5 2 4.9 ng N me2 s-l respectively for corn and soybean in the coastal region, tobacco in the Piedmont region, and corn in the upper Piedmont region. We were only able to detect an exponential dependence of NO flux on soil temperature at two of the locations. Tbe composite data of all the research sites revealed a general trend of increasing NO flux with soil water content or increasing extractable nitrogen in the soil, however, the day to day variations within each site did not reveal the same trends. We feel that acquisition of a soil NO flux data set in this fashion, which consists of observations collected over different points in both space and time, makes attempts to model soil NO flux in terms of different soil parameters difficult. DA - 1998/// PY - 1998/// DO - 10.1016/S0269-7491(98)80035-3 VL - 102 IS - SUPPL. 1 SP - 211-218 SN - 0269-7491 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0032446054&partnerID=MN8TOARS KW - natural emissions KW - nitric oxide KW - corn KW - soybean KW - tobacco KW - agricultural soils KW - soil moisture content KW - soil extractable nitrogen ER - TY - JOUR TI - Analysis of ammonia, ammonium aerosols and acid gases in the atmosphere at a commercial hog farm in eastern North Carolina, USA AU - McCulloch, RB AU - Few, GS AU - Murray, GC AU - Aneja, VP T2 - ENVIRONMENTAL POLLUTION AB - Measurements of atmospheric ammonia, acid gases, and ammonium aerosols were made at a commercial hog farm in Eastern North Carolina, USA, during September through December of 1997. Annular denuder systems (ADS) were used to sample gaseous (hydrogen chloride, nitrous acid, nitric acid, sulfur dioxide and ammonia) and fine aerosol (ammonium, chloride, nitrate, and sulfate) species. Ammonia and ammonium concentrations were determined by colorimetric analysis of the sample extracts. The acid gases and remaining fine particle ionic species were determined by ion chromatographic analysis of the sample extracts. Mean concentrations of the gaseous hydrogen chloride, nitrous acid, nitric acid, sulfur dioxide and ammonia were 0.743 μg/m3, 0.255 μg/m3, 0.154 μg/m3, 2.968 μg/m3, and 10.48 μg/m3, respectively. Mean concentrations of the fine particle chloride, nitrate, sulfate and ammonium were 0.321 μg/m3, 0.548 μg/m3, 3.247 μg/m3, and 1.102 μg/m3, respectively. The fine aerosol fraction was dominated by ammonium sulfate particles. A linear regression of sulfate versus ammonium by equivalent concentration showed a slope of 0.715 and r2 of 0.88. An emission factor for total ammonia nitrogen flux was estimated using a simple box model as approximately 5 to 10 kg animal−1 year−1. DA - 1998/// PY - 1998/// DO - 10.1016/S0269-7491(98)80042-0 VL - 102 IS - SUPPL. 1 SP - 263-268 SN - 0269-7491 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0032417540&partnerID=MN8TOARS KW - ammonia KW - ammonium KW - sulfate KW - aerosol KW - emissions ER - TY - JOUR TI - Spatiotemporal variation in postlarval recruitment of the Caribbean spiny lobster in the central Bahamas: lunar and seasonal periodicity, spatial coherence, and wind forcing AU - Eggleston, DB AU - Lipcius, RN AU - Marshall, LS AU - Ratchford, SG 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 174:33-49 (1998) - doi:10.3354/meps174033 Spatiotemporal variation in postlarval recruitment of the Caribbean spiny lobster in the central Bahamas: lunar and seasonal periodicity, spatial coherence, and wind forcing David B. Eggleston1,*, Romuald N. Lipcius2, Livingston S. Marshall Jr3, Stephen G. Ratchford1 1North Carolina State University, Department of Marine, Earth and Atmospheric Sciences, Raleigh, North Carolina 27695-8208, USA 2The College of William and Mary, School of Marine Science, Gloucester Point, Virginia 23062, USA 3Morgan State University, Biology Department, Baltimore, Maryland 21239, USA *E-mail: eggleston@ncsu.edu ABSTRACT: A large-scale recruitment study of the Caribbean spiny lobster Panulirus argus in the central Bahamas identified (1) strong spatial coherence in settlement to inshore nursery habitats, (2) temporal variability due in part to stochastic wind forcing, and (3) lunar and seasonal periodicity in settlement. First, we quantified lunar variation in settlement on standardized artificial substrates to determine whether or not intra- and inter-annual variability in recruitment could be adequately described by measuring influx of postlarvae during the first quarter of each new moon, as suggested by previous studies. Next, we compared settlement data obtained from artificial surface substrates to concentrations of postlarvae in the water column and benthic settlement. Long-term (6 yr) spatiotemporal variation in postlarval settlement was then quantified at 8 sites spanning a longitudinal and onshore distance of 43 km and 11 km, respectively. Lastly, we examined the relationship between postlarval settlement and environmental variables with time-series analyses. The key findings were that: (1) significant lunar (first quarter of lunar phase) and seasonal (fall peak) periodicities in settlement were consistent across sites; (2) postlarval settlement varied more across sites (~600%) than between years at a single site (~50%), and inter-site differences were consistent across time (i.e. some sites always had higher settlement than others); (3) settlement was correlated with along-shore winds blowing towards the southeast, but not with cross-shelf winds or water temperature; (4) floating, 'Witham-type' artificial settlement substrates yielded an accurate index of postlarval concentration and flux past a given point; and (5) floating substrates were a relatively poor indicator of benthic settlement, though the relationship between surface and benthic settlement may depend upon benthic habitat availability and postlarval supply. These results indicate that artificial settlement substrates provide a reliable index of postlarval supply to inshore nursery habitats, and that a combination of stochastic and deterministic forces influence recruitment over various scales of time and space. KEY WORDS: Environmental forcing · Panulirus argus · Larval supply · Recruitment · Settlement · Spiny lobster Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 174. Publication date: November 26, 1998 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1998 Inter-Research. DA - 1998/// PY - 1998/// DO - 10.3354/meps174033 VL - 174 IS - 1998 Nov. 26 SP - 33-49 SN - 0171-8630 KW - environmental forcing KW - Panulirus argus KW - larval supply KW - recruitment KW - settlement KW - spiny lobster ER - TY - JOUR TI - Atmospheric transmission in the ultraviolet and visible: Aerosols in cloudy atmospheres AU - Erlick, C AU - Frederick, JE AU - Saxena, VK AU - Wenny, BN T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - This study considers the effects of aerosols in cloudy atmospheres on the wavelength dependence of atmospheric transmission in the ultraviolet and visible parts of the solar spectrum. Normalizing the transmission to that of a cloud‐ and aerosol‐free atmosphere, we examine the competing influences of clouds and aerosols on the shape of the transmission function when clouds and aerosols are mixed; while pure water clouds cause the normalized transmission to decrease with wavelength from around 320 nm through the visible, aerosol particles cause the normalized transmission to increase with wavelength from 320 nm through the visible. The results show that when clouds are superimposed on an aerosol profile with the cloud drops and aerosol particles externally mixed, the shape of the normalized transmission spectrum is dominated by the effect of the cloud drops, unless the optical depth of the aerosols begins to approach the optical depth of the cloud. This is the case for an optically thin stratus cloud and an urban aerosol profile. When cloud drops and aerosol particles are internally mixed through coagulation, the shape of the normalized transmission spectrum is again dominated by the effect of the cloud drops, unless there is an unrealistically high volume fraction of strongly absorbing aerosols embedded in the droplets. While measurements of the mass fraction of absorbing aerosols such as soot in cloud and rainwater range from 3.0×10 −9 to 6.9×10 −6 , a soot volume fraction of 1×10 −4 is necessary to cause the normalized transmission to increase with wavelength from 320 nm through the visible. The model results are also shown to be consistent with Brewer spectrophotometer irradiance measurements under cloudy and hazy conditions. DA - 1998/12/27/ PY - 1998/12/27/ DO - 10.1029/1998JD200053 VL - 103 IS - D24 SP - 31541-31555 SN - 2169-8996 ER - TY - JOUR TI - Transition from pelagic to demersal phase in early-juvenile Nassau grouper, Epinephelus striatus, pigmentation, squamation, and ontogeny of diet AU - Grover, J. J. AU - Eggleston, D. B. AU - Shenker, J. M. T2 - Bulletin of Marine Science DA - 1998/// PY - 1998/// VL - 62 IS - 1 SP - 97-113 ER - TY - JOUR TI - The delta C-13 Of biogenic methane in marine sediments: the influence of C-org deposition rate AU - Blair, N T2 - CHEMICAL GEOLOGY AB - The δ13C of biogenic methane produced in marine sediments ranges from −110 to −55‰. The isotopic composition of the methane (δ13CCH4) is constrained by the fraction of metabolized organic carbon converted to CH4. The flux of labile organic carbon into the seabed (JMOC) and the availability of oxidants (Aox), such as O2 and SO4=, dictate that fraction, i.e., proportionately more methane should be produced as the ratio JMOC/Aox increases. Chemical, physical (e.g., sediment resuspension) and biological (bioturbation and bioirrigation) processes determine Aox. Given that δ13CCH4 is always less than δ13C of the metabolizable organic carbon, δ13CCH4 should increase when JMOC and the portion of metabolized carbon converted to methane increase. A positive linear correlation (r2=0.92) is observed between δ13CCH4 and JMOC for a database containing four continental margin sites. When the pore water sulfate gradient (ΔSO4=/Δdepth) is used as a surrogate for JMOC, the data set is extended to 15 locations spanning all latitudes. A linear relationship between the sulfate gradient and δ13CCH4 (r2=0.98) for shelf/slope environments suggests that either JMOC or JMOC/Aox is the master variable that controls the 13C/12C content of the biogenic methane. Carbonate precipitation and/or a methanogenic back reaction may obscure the correlation in deep-sea sediments. Evidence for the relationship between δ13CCH4 and JMOC appears to be preserved in Miocene-age dolomitic deposits. DA - 1998/10/26/ PY - 1998/10/26/ DO - 10.1016/S0009-2541(98)00102-8 VL - 152 IS - 1-2 SP - 139-150 SN - 0009-2541 KW - delta C-13 KW - biogenic methane KW - marine sediments ER - TY - JOUR TI - Size- and scale-dependent chemical attraction contribute to an ontogenetic shift in sociality AU - Ratchford, SG AU - Eggleston, DB T2 - ANIMAL BEHAVIOUR AB - Caribbean spiny lobsters,Panulirus argus, reside solitarily during the first months postsettlement, but shift to gregarious shelter use in later juvenile stages, at sizes as small as 15 mm in carapace length. To determine whether receptivity to or production of a chemical attractant among spiny lobster conspecifics is dependent upon body size or spatial scale, we conducted a series of overnight Y-maze shelter choice experiments. We placed a test lobster in an experimental arena and allowed it to choose between two shelters, which differed only in that water flowing by one shelter contained sea water that had passed through a header tank containing a conspecific. We varied the size of the lobster in the arena, the size and number of lobsters in the header tank, and the size of the experimental arena. Lobsters of all sizes tested released odours that attracted conspecifics; however, a single small lobster could attract other conspecifics only in the small arena. Lobsters greater than 15 mm in carapace length were attracted to shelters from which conspecific odours were emanating, while smaller lobsters were not. The results of this study suggest that: (1) the earliest benthic stages (less than 15 mm in carapace length) are unresponsive to conspecific odours, but lobsters greater than 15 mm in carapace length are attracted by conspecific odours; and (2) large lobsters produce a sufficient quantity of scent to attract conspecifics over distances of at least a few metres, whereas small lobsters (15–30 mm in carapace length) cannot. Body size- and spatial scale-dependent attraction could contribute to the shift from solitary to gregarious shelter use among Caribbean spiny lobsters. DA - 1998/10// PY - 1998/10// DO - 10.1006/anbe.1998.0869 VL - 56 IS - 4 SP - 1027-1034 SN - 0003-3472 ER - TY - JOUR TI - Seroprevalence of Toxoplasma gondii and Trichinella spiralis in North Carolina black bears (Ursus americanus) AU - Nutter, FB AU - Levine, JF AU - Stoskopf, MK AU - Gamble, HR AU - Dubey, JP T2 - JOURNAL OF PARASITOLOGY DA - 1998/10// PY - 1998/10// DO - 10.2307/3284644 VL - 84 IS - 5 SP - 1048-1050 SN - 0022-3395 ER - TY - JOUR TI - Faculty workshop on using instructional technologies and satellite data for college-level education in the atmospheric and earth sciences AU - Wetzel, M AU - Dempsey, D AU - Nilsson, S AU - Ramamurthy, M AU - Koch, S AU - Moody, J AU - Knight, D AU - Murphy, C AU - Fulker, D AU - Marlino, M AU - Morgan, M AU - Yarger, D AU - Vietor, D AU - Cox, G T2 - BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY AB - An education-oriented workshop for college faculty in the atmospheric and related sciences was held in Boulder, Colorado, during June 1997 by three programs of the University Corporation for Atmospheric Research. The objective of this workshop was to provide faculty with hands-on training in the use of Web-based instructional methods for specific application to the teaching of satellite remote sensing in their subject areas. More than 150 faculty and associated scientists participated, and postworkshop evaluation showed it to have been a very successful integration of information and activities related to computer-based instruction, educational principles, and scientific lectures. DA - 1998/10// PY - 1998/10// DO - 10.1175/1520-0477-79.10.2153 VL - 79 IS - 10 SP - 2153-2160 SN - 0003-0007 ER - TY - JOUR TI - Biogeochemical fluxes through the Strait of Otranto (eastern Mediterranean) AU - Civitarese, G AU - Gacic, M AU - Vetrano, A AU - Boldrin, A AU - Bregant, D AU - Rabitti, S AU - Souvermezoglou, E T2 - CONTINENTAL SHELF RESEARCH AB - A series of seasonal cruises and Eulerian current measurements in the Otranto Strait were carried out to study the biogeochemical characteristics of the strait and to estimate the exchange of water, dissolved and particulate matter between the Adriatic and the Ionian Sea. Analysis of data shows that on an annual scale, the Adriatic Sea exports dissolved nutrients (nitrate and phosphate) to the Ionian, and imports particulate organic carbon and nitrogen. Estimate of the mean annual water flux for the first time based on direct Eulerian current measurements gives value of 0.9 Sv that is appreciably higher than those found in literature. Calculations of the ratio of new and total primary production based on an annual phosphate subsurface export suggest that the trophic status of the Adriatic Sea on the whole is close to that of an oligotrophic sea. From the biogeochemical distributions obtained, an active role for the Adriatic in supporting the well-known N:P ratio anomaly of the Mediterranean is hy pothesized. Further studies are needed to estimate the contribution of the dissolved organic forms to the nutrient exchanges through the strait, and to establish the total budget of N and P in the Adriatic Sea. DA - 1998/6// PY - 1998/6// DO - 10.1016/S0278-4343(98)00016-8 VL - 18 IS - 7 SP - 773-789 SN - 0278-4343 ER - TY - JOUR TI - Anatomic site and interanimal variability in morphologic characteristics of bottlenose dolphin (Tursiops truncatus) skin likely to affect dermal absorption studies AU - Colbert, A. A. AU - Stoskopf, M. AU - Brownie, C. AU - Scott, G. I. AU - Levine, J. T2 - American Journal of Veterinary Research DA - 1998/// PY - 1998/// VL - 59 IS - 11 SP - 1398-1403 ER - TY - JOUR TI - An experimental chain of infection reveals that distinct Borrelia burgdorferi populations are selected in arthropod and mammalian hosts AU - Ryan, , JR AU - Levine, JF AU - Apperson, CS AU - Lubke, L AU - Wirtz, RA AU - Spears, PA AU - Orndorff, PE T2 - MOLECULAR MICROBIOLOGY AB - The prokaryotic, spirochaetal microorganism Borrelia burgdorferi is the causative agent of Lyme disease, an arthropod‐borne disease of a variety of vertebrates and the most prevalent arthropod‐borne disease of humans in the United States. In order to understand better the normal life cycle of B. burgdorferi , an experimental chain of infection was devised that involved multiple sequential arthropod and mammalian passages. By examining populations of B. burgdorferi emerging from different points in this infectious chain, we demonstrate that selection of B. burgdorferi populations peculiar to arthropod or vertebrate hosts is a property of at least one of the two ecologically distinct strains we examined. Distinct B. burgdorferi populations were identified using an antigenic profile, defined by a set of monoclonal antibodies to eight B. burgdorferi antigens, and a plasmid profile, defined by the naturally occurring plasmids in the starting clonal populations. These two profiles constituted the phenotypical signature of the population. In the strain exhibiting selection in the different hosts, transition from one host to another produced a striking series of alternating phenotypical signatures down the chain of infection. At the molecular level, the alternating signatures were manifested as a reciprocal relationship between the expression of certain antigenic forms of outer surface protein (Osp) B and OspC. In the case of OspC, the antigenic changes could be correlated to the presence of one of two distinctly different alleles of the ospC gene in a full‐length and presumably transcriptionally active state. In the case of OspB, two alleles were again identified. However, their differences were minor and their relationship to OspB antigenic variation more complicated. In addition to the reciprocating changes in the antigenic profile, a reciprocating change in the size (probably the multimeric state) of a 9.0 kbp supercoiled plasmid was also noted. Selection of distinct populations in the tick may be responsible for the microorganism's ability to infect a wide range of vertebrate hosts efficiently, in that the tick might provide selective pressure for the elimination of the population selected in the previous host. DA - 1998/10// PY - 1998/10// DO - 10.1046/j.1365-2958.1998.01071.x VL - 30 IS - 2 SP - 365-379 SN - 1365-2958 ER - TY - BOOK TI - A Paradox of power: Voices of warning and reason in the geosciences AU - Welby, C. W. AU - Gowan, M. E. AB - The 13 papers in this volume illustrate issues and opportunities confronting geologists as they bring their knowledge and understanding to bear in matters related to public health and welfare. Public decisions and decision-making processes in the face of geologic complexity and uncertainty are the subject of the first group of papers. In the second group, several “voice of warning” papers illustrate the use of geologic knowledge and research to warn the public of health hazards derived from geologic materials and processes. A third group of papers, in the “voice of reason” section, describes use of geologic knowledge to help lower the costs of mitigation and avoidance of geologic hazards. Finally, ethical and philosophical questions confronting geoscientists are discussed and issues of “truth” as related to the legal process and questions about the adequacy of information in making decisions about long-term radioactive waste disposal are discussed. CN - TA705 .R4 vol. 12 1998 DA - 1998/// PY - 1998/// DO - 10.1130/reg12 PB - Boulder, Colo.: Geological Society of America SN - 0813741122 ER - TY - JOUR TI - Ontogenetic diet shifts in Nassau grouper: Trophic linkages and predatory impact AU - Eggleston, D. B. AU - Grover, J. J. AU - Lipcius, R. N. T2 - Bulletin of Marine Science DA - 1998/// PY - 1998/// VL - 63 IS - 1 SP - 111-126 ER - TY - JOUR TI - Numerical simulation of the sensitivity of summer monsoon circulation and rainfall over India to land surface processes AU - Raman, S AU - Mohanty, UC AU - Reddy, NC AU - Alapaty, K AU - Madala, RV T2 - PURE AND APPLIED GEOPHYSICS DA - 1998/10// PY - 1998/10// DO - 10.1007/s000240050178 VL - 152 IS - 4 SP - 781-809 SN - 0033-4553 KW - numerical simulation KW - summer monsoon KW - circulation KW - land surface KW - parameterization ER - TY - JOUR TI - Modeling the effects of meteorology on ozone in Houston using cluster analysis and generalized additive models AU - Davis, JM AU - Eder, BK AU - Nychka, D AU - Yang, Q T2 - ATMOSPHERIC ENVIRONMENT AB - This paper compares the results from a single-stage clustering technique (average linkage) with those of a two-stage technique (average linkage then k-means) as part of an objective meteorological classification scheme designed to better elucidate ozone’s dependence on meteorology in the Houston, Texas, area. When applied to twelve years of meteorological data (1981–1992), each clustering technique identified seven statistically distinct meteorological regimes. The majority of these regimes exhibited significantly different daily 1 h maximum ozone (O3) concentrations, with the two-stage approach resulting in a better segregation of the mean concentrations when compared to the single-stage approach. Both approaches indicated that the largest daily 1 h maximum concentrations are associated with migrating anticyclones that occur most often during spring and summer, and not with the quasi-permanent Bermuda High that often dominates the southeastern United States during the summer. As a result, maximum ozone concentrations are just as likely during the months of April, May, September and October as they are during the summer months. Generalized additive models were then developed within each meteorological regime in order to identify those meteorological covariates most closely associated with O3 concentrations. Three surface wind covariates: speed, and the u and v components were selected nearly unanimously in those meteorological regimes dominated by anticyclones, indicating the importance of transport within these O3 conducive meteorological regimes. DA - 1998/8// PY - 1998/8// DO - 10.1016/S1352-2310(98)00008-9 VL - 32 IS - 14-15 SP - 2505-2520 SN - 1352-2310 KW - ozone KW - cluster analysis KW - meteorology KW - generalized additive models KW - Houston ER - TY - JOUR TI - A study of regional aerosol radiative properties and effects on ultraviolet-B radiation AU - Wenny, BN AU - Schafer, JS AU - DeLuisi, JJ AU - Saxena, VK AU - Barnard, WF AU - Petropavlovskikh, , IV AU - Vergamini, AJ T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - A field experiment was conducted in western North Carolina to investigate the relationship between aerosol optical properties and atmospheric transmission. Two research measurement sites in close horizontal proximity but at different altitudes were established to measure the transmission of UV radiation through a slab of atmosphere. An identical set of radiation sensing instruments, including a broadband UV‐B radiometer, a direct Sun pyrheliometer, a shadowband radiometer, and a spectral photometer, was placed at both sites, a mountaintop site (Mount Gibbes 35.78°N, 82.29°W, 2004 m elevation) and a valley site (Black Mountain, North Carolina 35.66°N, 82.38°N, 951 m elevation). Aerosol size distribution sampling equipment was located at the valley site. Broadband solar pseudo‐optical depth and aerosol optical depths at 415 nm, 500 nm, and 673 nm were measured for the lowest 1‐km layer of the troposphere. The measurements exhibited variations based on an air mass source region as determined by back trajectory analysis. Broadband UV‐B transmission through the layer also displayed variations relating to air mass source region. Spectral UV transmission revealed a dependence upon wavelength, with decreased transmission in the UV‐B region (300–320 nm) versus UV‐A region (320–363.5 nm). UV‐B transmission was found to be negatively correlated with aerosol optical depth. Empirical relations were developed to allow prediction of solar noon UV‐B transmission if aerosol optical depth at two visible wavelengths (415 and 500 nm) is known. A new method was developed for determining aerosol optical properties from the radiation and aerosol size distribution measurements. The aerosol albedo of single scatter was found to range from 0.75 to 0.93 and the asymmetry factor ranged from 0.63 to 0.76 at 312 nm, which is close to the peak response of human skin to UV radiation. DA - 1998/7/27/ PY - 1998/7/27/ DO - 10.1029/98JD01481 VL - 103 IS - D14 SP - 17083-17097 SN - 2169-897X ER - TY - JOUR TI - A new method to measure the terminal velocity of small particles: A demonstration using ascending eggs of the Atlantic menhaden (Brevoortia tyrannus) AU - Cambalik, JJ AU - Checkley, DM AU - Kamykowski, D T2 - LIMNOLOGY AND OCEANOGRAPHY AB - A new method, incorporating video, motion analysis, and a novel experimental apparatus, was used to measure the terminal velocity of particles. The method facilitated the investigation of treatment effects and maximized the number of measurements For each replicate, thus improving the statistics for a population of particles. The eggs of the Atlantic menhaden ( Brevoortia tyrannus ) were used to demonstrate the method by investigating the effects of salinity and stage of development on their ascent rate. Egg ascent rate was greatest at intermediate salinity (36.5‰) and decreased in the late stage of embryonic development. We estimate eggs at oceanic salinities (>35.5‰) in nature to ascend at 0.19–0.25 cm s −1 . DA - 1998/11// PY - 1998/11// DO - 10.4319/lo.1998.43.7.1722 VL - 43 IS - 7 SP - 1722-1727 SN - 0024-3590 ER - TY - JOUR TI - Searching for a regional fingerprint of aerosol radiative forcing in the southeastern US AU - Saxena, VK AU - Yu, SC T2 - GEOPHYSICAL RESEARCH LETTERS AB - Although aerosols have long been considered to exert a cooling influence on the regional climate due to direct and indirect radiative forcing, persuasive evidence of the response to this forcing has been lacking. Here, we analyze the regional patterns of climate change in the Southeast US during the period 1949–94 to search for a fingerprint of aerosol radiative forcing. The results show that direct and indirect radiative forcing of both natural (such as Pinatubo volcanic aerosols) and anthropogenic aerosols (such as those transported from the polluted regions of US) may be responsible for the regional cooling trend in the Southeast during the past 46 years. Lack of availability of long term measurements precludes a rigorous cause‐and‐effect analysis. Circumstantial evidence presented here amply justifies immediate establishment of a network of measurements of aerosol optical depth and cloud reflectivity in the southeastern US. DA - 1998/8/1/ PY - 1998/8/1/ DO - 10.1029/98GL02106 VL - 25 IS - 15 SP - 2833-2836 SN - 0094-8276 ER - TY - JOUR TI - Priorities of the academic community for the National Weather Service AU - Dutton, JA AU - Pietrafesa, LJ AU - Snow, JT T2 - BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY AB - *The Pennsylvania State University, University Park, Pennsylvania.+North Carolina State University at Raleigh, Raleigh, North Carolina.#University of Oklahoma, Norman, Oklahoma.Corresponding author address: John A. Dutton, The Pennsylvania State University, 116 Duke Building, University Park, PA 16802-2710. DA - 1998/5// PY - 1998/5// DO - 10.1175/1520-0477(1998)079<0761:POTACF>2.0.CO;2 VL - 79 IS - 5 SP - 761-763 SN - 1520-0477 ER - TY - JOUR TI - Low-field bulk defect generation during uniform carrier injection into the gate insulator of insulated gate field effect transistors at various temperatures AU - Kim, HS AU - Williams, CK AU - Reisman, A T2 - JOURNAL OF ELECTRONIC MATERIALS DA - 1998/7// PY - 1998/7// DO - 10.1007/s11664-998-0117-0 VL - 27 IS - 7 SP - 908-914 SN - 0361-5235 KW - electron trapping KW - oxide defects KW - trap generation ER - TY - JOUR TI - Estuarine fronts as conduits for larval transport: hydrodynamics and spatial distribution of Dungeness crab postlarvae AU - Eggleston, DB AU - Armstrong, DA AU - Elis, WE AU - Patton, WS 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 164:73-82 (1998) - doi:10.3354/meps164073 Estuarine fronts as conduits for larval transport: hydrodynamics and spatial distribution of Dungeness crab postlarvae David B. Eggleston1,*, David A. Armstrong2, Ward E. Elis1, William S. Patton2 1Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695-8202, USA 2University of Washington, School of Fisheries, Box 357980, Seattle, Washington 98195, USA *E-mail: eggleston@ncsu.edu Frontal zones are common hydrographic features in estuaries throughout the world, yet there is no consensus on the importance of fronts to larval transport processes. Frontal circulation may act as a 'barrier' to larval transport since it constrains cross-frontal flows, leading to strong along-frontal flows, which in turn may serve as a type of 'larval conduit' by funneling larvae collected at the front to settlement locations. We examined the larval conduit hypothesis by characterizing hydrodynamic features of apparent frontal structure in Grays Harbor estuary (Washington, USA) and quantifying the effects of frontal structure on the distribution and transport potential of Dungeness crab Cancer magister megalopae during spring-time recruitment pulses. CTD casts made perpendicular to fronts indicated that frontal structure was characteristic of buoyant plume and axial convergent fronts at the bay mouth and at a subtidal channel site within the estuary, respectively. Surface drifters deployed seaward of a front at the bay mouth during early flood tide were advected into the front, demonstrating convergent circulation. Surface drifters remained within buoyant plume fronts, which moved up-estuary during flood tide at 0.4 m s-1, and were then entrained in axial convergent fronts. Drifters moved an average of 10 km up-estuary during a single flood tide; the direction that drifters tracked corresponded to prevailing winds. The mean concentration of megalopae, as measured with neuston nets, was significantly higher in fronts than in adjacent water, 20 to 30 m upstream of the front, irrespective of year or location within the estuary. Paired plankton nets deployed at the bay mouth during flood tide indicated that the mean concentration and flux of megalopae was higher at the surface than at 3 to 4 m depth; this trend was significant for megalopal flux. Variable wind stress during the recruitment period of Dungeness crab, combined with the suggested effect of fronts serving as larval conduits whose direction of transport is influenced by prevailing winds, could significantly influence spatial variation in postlarval supply and subsequent settlement within the estuary. Cancer magister · Drifters · Dungeness crab · Estuarine hydrodynamics · Fronts · Larval transport · Recruitment Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 164. Publication date: April 09, 1998 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1998 Inter-Research. DA - 1998/// PY - 1998/// DO - 10.3354/meps164073 VL - 164 IS - 1998 Apr. 9 SP - 73-82 SN - 0171-8630 KW - Cancer magister KW - drifters KW - dungeness crab KW - estuarine hydrodynamics KW - fronts KW - larval transport KW - recruitment ER - TY - CONF TI - Climatological and regional analyses of CASTNet air concentration data AU - Eder, B. K. AU - Sickles, J. E. C2 - 1998/// 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 - 1998/// SP - 402-413 PB - Pittsburgh, Pa.: A&WMA ER - TY - JOUR TI - Alkalic magma modified by incorporation of diverse tholeiitic components: 'complex' hybridization on Kahoolawe island, Hawaii AU - Fodor, RV AU - Bauer, GR AU - Jacobs, RS T2 - MINERALOGY AND PETROLOGY DA - 1998/// PY - 1998/// DO - 10.1007/BF01162769 VL - 63 IS - 1-2 SP - 73-94 SN - 0930-0708 ER - TY - JOUR TI - The 1994-1996 Arabian Sea Expedition: An integrated, interdisciplinary investigation of the response of the northwestern Indian Ocean to monsoonal forcing AU - Smith, SL AU - Codispoti, LA AU - Morrison, JM AU - Barber, RT T2 - DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY DA - 1998/// PY - 1998/// DO - 10.1016/S0967-0645(98)00058-7 VL - 45 IS - 10-11 SP - 1905-1915 SN - 0967-0645 ER - TY - JOUR TI - Structural geology of the High Rock granite: Implications for displacement along the Hyco Shear zone, North Carolina AU - Vines, J. A. AU - Hibbard, J. P. AU - Shell, G. S. T2 - Southeastern Geology DA - 1998/// PY - 1998/// VL - 37 IS - 4 SP - 163- ER - TY - JOUR TI - Seasonal variation of hydrographic and nutrient fields during the US JGOFS Arabian Sea Process Study AU - Morrison, JM AU - Codispoti, LA AU - Gaurin, S AU - Jones, B AU - Manghnani, V AU - Zheng, Z T2 - DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY AB - Between September 1994 and December 1995, the US JGOFS Arabian Sea Process Experiment collected extensive, high quality hydrographic data (temperature, salinity, dissolved oxygen and nutrients) during all seasons in the northern Arabian Sea. An analysis of this unique data suite suggests the presence of many features that are described in the canonical literature, but these new data provided the following insights. Although the seasonal evolution of mixed-layer depths was in general agreement with previous descriptions, the deepest mixed-layer depths in our data occurred during the late NE Monsoon instead of the SW Monsoon. The region exhibits considerable mesoscale variability resulting in extremely variable temperature-salinity (TS) distributions in the upper 1000 db. This mesoscale variability is readily observed in satellite imaging, in the high resolution data taken by a companion ONR funded project, and in underway ADCP data. The densest water reaching the sea surface during coastal upwelling appeared to have maximum offshore depths of ∼150 m and σθ’s close to the core value (∼25) for the saline Arabian Sea Water (ASW), but salinities in these upwelling waters were relatively low. The densest water found at the sea surface during late NE Monsoon conditions has σθ’s>24.8 and relatively high salinities, suggesting that they are a source for the ASW salinity maximum. Persian Gulf Water (PGW) with a core σθ of 26.6 forms a widespread salinity maximum. Despite the considerable extent of this feature, Persian Gulf outflow water, with a salinity (4) of ∼39 at its source, can only be a minor contributor. Within the standard US JGOFS sampling grid, maximum salinities on this surface are ∼36.8 at stations near the Gulf, falling to values as low as ∼35.3 at the stations farthest removed from its influence. Even at our standard stations closest to the Gulf (N-1 and N-2), the high-salinity, low-nutrient Persian Gulf water has only a modest direct effect on nutrient concentrations. This PGW salinity maximum is associated with the suboxic portions of the Arabian Sea’s oxygen minimum zone. The salinity maximum associated with Red Sea Water (RSW, core σθ=27.2) in the JGOFS study region is clearly evident at the southermost sampling site at 10′N (S-15). Elsewhere, this signal is weak or absent and salinity on the 27.2 σθ surface tends to increase towards the Persian Gulf, suggesting that the disappearance of this salinity maximum is due, at least in part, to the influence of the Persian Gulf outflow. Inorganic nitrogen-to-phosphate ratios were lower (frequently much lower) than the standard Redfield ratio of 15/1–16/1 (by atoms) at all times and all depths suggesting that inorganic nitrogen was more important than phosphate as a limiting nutrient for phytoplankton growth, and that the effects of denitrification dominated the effects of nitrogen fixation. The water upwelling off the Omani coast during the SW Monsoon has inorganic nitrogen to silicate ratios that were higher (∼2/1) than the ∼1/1 ratio often assumed as the ratio of uptake during diatom growth. The temporal evolution of inorganic nitrogen-to-silicate ratios suggests major alteration by diatom uptake only during the late SW Monsoon cruise (TN050) in August–September 1995. Widespread moderate surface layer nutrient concentrations occurred during the late NE Monsoon. A zone of high offshore nutrient concentrations was encountered during the SW Monsoon, but instead of being associated with offshore upwelling it may represent offshore advection from the coastal upwelling zone, the influence of an eddy, or both. Although our data do not contradict previous suggestions that the volume of subtoxic water may be reduced the SW Monsoon, they suggest a weaker re-oxygenation than indicated by some previous work. Similarly, they do not confirm results suggesting that secondary nitrite maxima may be common in waters with oxygen concentrations >5 μM. DA - 1998/// PY - 1998/// DO - 10.1016/S0967-0645(98)00063-0 VL - 45 IS - 10-11 SP - 2053-2101 SN - 0967-0645 ER - TY - JOUR TI - Role of sulfates in regional cloud-climate interactions AU - Menon, S AU - Saxena, VK T2 - ATMOSPHERIC RESEARCH AB - Abstract During the summers of 1993–1996, field experiments were conducted at Mt. Mitchell, NC, in the southeastern US. The effect of anthropogenic pollution on cloud microphysical properties such as liquid water content (ω), cloud droplet number concentration (N), effective radii (Reff), cloud condensation nuclei (CCN) activation spectrum and cloud reflectivity were investigated. Cloud water sulfate concentration was used as a measure of anthropogenic pollution. Back trajectory analysis was used to categorize the cloud forming air masses that arrived at the site. The sulfates and nitrates emission inventories of the U.S. Environmental Protection Agency (EPA) were used to classify air masses as polluted marine (PM), polluted continental (PC) or as highly polluted (HP). Empirical values for the relationships between CCN–N, CCN–sulfate, N–sulfate and Reff–N for different air masses have been obtained. A quantitative nonlinear relationship between CCN and N was obtained. The sublinear relationship between CCN and sulfate mass indicated the susceptibility of the different air masses to the sulfate content. The lesser polluted air masses exhibited greater changes in CCN concentrations for smaller increases in sulfate mass concentrations as compared to the more polluted air masses. The relationship between Reff and N for different air masses, as well as the N–sulfate mass relationship, suggested that the counteracting effect of sulfates on greenhouse warming for the southeastern US would be of magnitude greater than −4.0 W m−2 obtained by modeling studies. The nonlinear relationships between the cloud microphysical/optical properties and the sulfate content of the air mass implies the existence of an optimum level for the sulfate concentration beyond which cloud reflectivity stays unaffected. Analysis of 3 years of observational data established this level at 400–500 μeq l−1 of sulfate in the cloud water. DA - 1998/6// PY - 1998/6// DO - 10.1016/S0169-8095(98)00057-X VL - 48 SP - 299-315 SN - 1873-2895 KW - cloud water KW - anthropogenic pollution KW - polluted air masses KW - cloud reflectivity KW - greenhouse warming ER - TY - JOUR TI - Relationships between geotaxis/phototaxis and diel vertical migration in autotrophic dinoflagellates AU - Kamykowski, D. AU - Milligan, E.J. AU - Reed, R.E T2 - Journal of Plankton Research AB - Marine dinoflagellate diel vertical migrations are often conceptually explained by a species' geotactic and phototactic preferences, but actual simultaneous measurements are rare. Newly collected simultaneous measurements on Heterocapsa ( Cachonina ) illdefina (Herman and Sweeney) and Gymnodinium breve (Davis) are combined with similar literature information on Amphidinium carterae (Hulbert), Peridinium faeroense (Paulsen) and Prorocentrum micans (Ehrenberg) to explore several examples of the actual relationships between diel vertical migration and geotaxis/phototaxis. Amphidinium carterae does not migrate, but it exhibits a negative geotaxis that may counter a small sinking velocity. The four other species all exhibit diel vertical migrations that yield surface aggregations during daylight, but the associated combinations of geotaxis and phototaxis precision (which is strongest when every cell in a population exhibits the same response to a stimulus and weakest when the response is random) and sign [which is positive (negative) when motion is toward (away from) the stimulus] are different in each case. These different taxis combinations may be related to species-specific sensor structure and/or placement. Furthermore, variations in the different biochemical pools over a species' cell cycle may contribute to structural/mechanical changes that influence how a given sensory array functions at a given time. If so, this coupling may be an important link in the growth optimization mechanisms and occasional bloom successes of different autotrophic dinoflagellate species under varying environmental conditions. DA - 1998/// PY - 1998/// DO - 10.1093/plankt/20.9.1781 VL - 20 IS - 9 SP - 1781-1796 J2 - J Plankton Res LA - en OP - SN - 0142-7873 1464-3774 UR - http://dx.doi.org/10.1093/plankt/20.9.1781 DB - Crossref ER - TY - JOUR TI - Quadrupole moments and identical superdeformed bands in Tb-149 AU - Kharraja, B. AU - Garg, U. AU - Jin, H. AU - Ernst, R. J. AU - Ghugre, S. S. AU - Janssens, R. V. F. AU - Carpenter, M. P. AU - Fischer, S. M. AU - Khoo, T. L. AU - Lauritsen, T. AU - Nisius, D. AU - Moore, E. F. AU - Byrski, T. AU - Krucken, R. AU - Macchiavelli, A. O. AU - al., T2 - Physical Review. C, Nuclear Physics DA - 1998/// PY - 1998/// VL - 58 IS - 3 SP - 1422-1429 ER - TY - JOUR TI - Isotopic and trace-element indications of lithospheric and asthenospheric components in Tertiary alkalic basalts, northeastern Brazil AU - Fodor, RV AU - Mukasa, SB AU - Sial, AN T2 - LITHOS AB - Plate reconstructions at 30 Ma place northeastern Brazil over the Fernando de Noronha hotspot, presently ∼250 km offshore northeastern Brazil. Tertiary basaltic centers in northeastern Brazil may therefore be products of the Fernando de Noronha hotspot. We examined alkalic basalt from seven ∼30–13 Ma old centers in Rio Grande do Norte and Pernambuco states to assess this possible link. Compositions are primitive, where MgO concentrations range from 12.5 to 17 wt.%, and SiO2 from ∼41 to 48 wt.%. Trace-element abundances and Sr, Nd, and Pb isotopic compositions compare well with those of ocean island basalt: 87Sr/86Sr=∼0.7038–0.7051, 143Nd/144Nd=∼0.51266–0.51280, and 206Pb/204Pb=∼18.52–19.35. There are correlations among SiO2-undersaturation, incompatible-element abundances, relative percentages of partial melting (based on La/Yb and La/Y ratios), and the degree of isotopic `enrichment' inherited from mantle sources. There is also a negative correlation for La/Nb (∼0.6–0.86) vs. Ba/Nb (6.6–10.6), where lower La/Nb samples represent larger percentages of melting of a source comparatively enriched in radiogenic Sr. We attribute these compositional relationships to the lavas representing mixing of melts mainly from asthenosphere of largely HIMU plus DM characterization, probably the Fernando de Noronha plume, with melts from subcontinental lithosphere that was isotopically closer to EM1. Isotopic and trace-element compositions of the northeastern Brazil basalts are generally similar to those of Fernando de Noronha lavas (12–2 Ma), and some minor trace-element differences observed (e.g., more Zr, Nb, and less Th compared to northeastern Brazil basalts) are probably due to heterogeneity within the asthenospheric plume and to melt contributions from delaminated subcontinental lithosphere that may underlie Fernando de Noronha. DA - 1998/9// PY - 1998/9// DO - 10.1016/S0024-4937(98)00012-7 VL - 43 IS - 4 SP - 197-217 SN - 0024-4937 KW - basalt KW - Brazil KW - trace-elements KW - isotopes KW - mineral compositions ER - TY - JOUR TI - An experimental study of the flow structure within a dense gas plume AU - Zhu, GW AU - Arya, SP AU - Snyder, WH T2 - JOURNAL OF HAZARDOUS MATERIALS AB - A wind tunnel study was conducted to examine how a dense gas plume could affect the mean flow and turbulence structure of the boundary layer containing the plume. For this, a neutral atmospheric boundary layer developing over an aerodynamically rough surface was simulated in the US EPA's Meteorological Wind Tunnel. The dense gas plume was created by releasing CO2 through a small circular source at ground level. A procedure was developed to make reasonably accurate mean velocity and turbulence measurements within the dense gas plumes by using hot-film anemometry in a range where the probe response was insensitive to the concentration of CO2. Both the flow visualization and quantitative measurements of concentration and velocity fields indicated that, at low wind speeds, the dense gas plumes exhibited significant buoyancy effects on the flow structure. Within the dense plumes, mean velocity profiles were observed to have changed significantly in shape, with reduced speeds near the surface and increased velocities farther away from the surface. Consistent with these changes in mean velocity profiles, significant reductions in the roughness length and friction velocity were observed. Both the longitudinal and vertical turbulence intensities were also found to be greatly reduced within the dense plumes at low wind speeds. These changes in mean flow and turbulence structure were not only related to the dense-gas concentrations, but also to the local velocity gradients and the growth of the dense plumes with distance from the source. The local gradient Richardson number is found to be the most appropriate parameter for describing the changes in the mean flow and turbulence structure. Significant dense gas effects were observed when the Richardson number increased beyond its critical value (0.25) for the dynamic stability of a stratified flow. Our experimental results show that, in an existing turbulent flow, turbulence is not completely suppressed even when the gradient Richardson number exceeds one. DA - 1998/9/25/ PY - 1998/9/25/ DO - 10.1016/S0304-3894(98)00162-9 VL - 62 IS - 2 SP - 161-186 SN - 0304-3894 KW - concentration distributions KW - dense gas dispersion KW - flow visualization fluid modeling KW - hazardous material KW - modeling criteria KW - plume dispersion KW - turbulence intensities KW - velocity profile ER - TY - JOUR TI - An analysis of chemical composition of different rain types in 'Minnan Golden Triangle' region in the southeastern coast of China AU - Yu, S. C. AU - Gao, C. T. AU - Cheng, Z. M. AU - Cheng, X. J. AU - Cheng, S. T. AU - Xiao, J. A. AU - We, W. X. T2 - Atmospheric Research AB - The pollutants from anthropogenic activities can affect precipitation composition and subsequently affect aquatic and terrestrial ecosystems. Here, we reported the results from the simultaneous collection and chemical analysis (including F−, Cl−, NO3−, SO42−, HCOO−, CH3COO−, Na+, NH4+, K+, Ca2+, Mg2+, pH) of spring rain, mold rain and typhoon rain during 1990 and 1991 in the region of Xiamen, Quanzhou, Zhangzhou and Tongan, which is called `Minnan Golden Triangle' and is a rapidly growing urban area in the southeastern Coast of China. It was found that the average pHs of spring rain, mold rain and typhoon rain in 1990 in this region were 4.51, 4.93 and 5.14, respectively. Obviously, the spring rain was the most acidic in the three types of rains in this region. The average concentrations of formic and acetic acids in Xiamen mold rain were 5.67 and 2.91 μeq/l, respectively, and the average maximum contribution of organic acids to free acidity was in the range of 2.8% to 100% (average 66.3%). The regression equations between acidity and ions showed that SO42, NO3−, NH4+ and organic acids (formic and acetic) made the major contribution to the precipitation acidity in this region. The chemical characteristics of different precipitation types in this region indicated that spring rain had the character of continental origin, but the mold rain and typhoon rain had more effects from ocean. Since spring rain, mold rain, and typhoon rain were caused by precipitation cloud approaching to this region from different directions and had different acidity, and the average pH of cloud rainwater on the mountain site was 4.90, it is suggested that acid rain in this region might be mainly caused by long-range transport of pollutants from the southern Chinese mainland, and the local pollution sources were less as significant. DA - 1998/// PY - 1998/// DO - 10.1016/s0169-8095(98)00047-7 VL - 48 IS - Spec. Iss. SP - 245-269 ER - TY - CHAP TI - Airborne particles and mortality AU - Smith, R. L. AU - Davis, J. M. AU - Speckman, P. T2 - Case studies in environmental statistics A2 - D. Nychka, W. W. Piegorsch A2 - Cox, L. H. AB - In London in December 1952, a combination of adverse weather conditions and soot in the atmosphere produced one of the most lethal smogs in history, resulting in thousands of deaths. Similar events had occurred earlier in the Meuse Valley in Belgium in 1930, and in Donora, Pennsylvania in 1948. They focused attention on the need to avoid excessive levels of soot in the atmosphere. In Britain, the Clean Air Act of 1956, which, among other things, placed severe restrictions on the use of coal for home heating, resulted in a tenfold reduction in soot levels in London by the late 1960s. In the United States, the creation of the Environmental Protection Agency (EPA) and the passing of successive Clean Air Acts by Congress led to the enforcement of air pollution standards which have laid down strict controls on levels of ozone and particulate matter in the atmosphere. Nevertheless, a series of studies since the late 1980s have suggested that current standards are by no means strict enough. The New York Times (July 19, 1993) reported that up to 60,000 people a year are dying prematurely in the United States as a result of particulate matter pollution which for the most part lies within current EPA standards. A similar calculation in the British science magazine The New Scientist (March 12, 1994) concluded that 10,000 people die prematurely each year in England and Wales, as a result of atmospheric particulates. Such reports, backed up by many papers in the scientific literature, naturally led to calls for action, and in November 1996, the EPA issued new draft standards for ozone and particulate matter. CN - GE45.S73 C38 1998 PY - 1998/// DO - 10.1007/978-1-4612-2226-2_6 PB - New York: Springer ER - TY - JOUR TI - Advection of upwelled waters in the form of plumes off Oman during the Southwest Monsoon AU - Manghnani, V AU - Morrison, JM AU - Hopkins, TS AU - Bohm, E T2 - DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY AB - Advanced Very High Resolution Radiometer (AVHRR) imagery of sea-surface-temperature, TOPEX/POSEIDON measurements of sea-level-anomaly (SLA), and modeled surface winds and wind-stress fields are used in concert with other ancillary data to describe the influence of the 1995 Southwest Monsoon on the distribution of upwelled waters off the coast of Oman. The Oman upwelling zone is characterized by the entrainment of cold upwelled waters into plumes extending from the coast into the deep ocean unaffected by the steep bottom gradients. The most prominent of these plumes is found offshore of Ras al Madraka. A mechanism for the entrainment of upwelled water into plumes is hypothesized, and validated by observational data. It is proposed that the location of the plume is primarily governed by the sea level structure away from the coast and that coastally upwelled water is passively advected offshore through regions of low sea level. Analysis of the surface wind-stress fields show significant spatial variability associated with the predominantly cyclonic mean wind-stress curl, with relatively weak curl observed in the region south of Ras al Madraka and north of Ras Marbat. Decomposition of the surface wind-stress fields through Principal Component Analysis shows that, at certain periods, the development of strong along-shore winds and cyclonic wind-stress curl in the region north of Ras al Madraka. This information, combined with concurrent observations of TOPEX/POSEIDON sea-level-anomalies (SLAs), satellite derived sea-surface-temperatures (SST), and surface current measurements, shows that the combined effects of a strong along-shore wind field and positive wind-stress curl forces a depression in sea level in the region north of Ras al Madraka. The sea level gradient, caused by the presence of a sustained high sea level to the south of Ras al Madraka, causes geostrophic advection of coastally upwelled waters away from the shelf. Acoustic Doppler Current Profiler (ADCP) velocity measurements along with SST maps further prove that the upwelled water is geostrophically advected offshore as opposed to being an offshore deflection of a wind-driven coastal current. Comparison of interannual features in the TOPEX/POSEIDON SLAs suggest that the plumes coming off coast in the Oman upwelling zone may not be directly linked to the coastal topography or bathymetry but are a result of interaction between mesoscale variations in the wind field and the underlying ocean. The strong along-shore winds and cyclonic wind-stress curl to the north of Ras al Madraka becomes enhanced when the Findlater Jet moves closer to the Oman coast than its mean position. DA - 1998/// PY - 1998/// DO - 10.1016/S0967-0645(98)00062-9 VL - 45 IS - 10-11 SP - 2027-2052 SN - 0967-0645 ER - TY - JOUR TI - The Hyco shear zone in North Carolina and southern Virginia: Implications for the Piedmont zone Carolina zone boundary in the southern Appalachians AU - Hibbard, JP AU - Shell, GS AU - Bradley, PJ AU - Samson, SD AU - Wortman, GL T2 - AMERICAN JOURNAL OF SCIENCE AB - The recently recognized Hyco shear zone is a first-order structure in the southern Appalachians that separates sharply contrasting rocks of the Carolina and Milton terranes in north central North Carolina and southern Virginia. Traditionally, this boundary has been viewed as a comformable contact between infrastructural Milton rocks and suprastructural Carolina rocks. In contrast, our work indicates that shallowly dipping, sillimanite gneisses of the Milton terrane comprise the footwall of the ductile shear zone whereas moderately to steeply-dipping greenschist to amphibolite facies Carolina terrane gneisses and metavolcanics form the hangingwall. The Hyco shear zone has a sharply arcuate surface trace: it trends east-northeast in the area of Hyco Lake, North Carolina, and abruptly changes trend to north-northeast near the North Carolina-Virginia state line. The zone is moderately to steeply south-southeast-dipping along the Hyco Lake segment, and structures there indicate dominantly dextral strike slip. Along the Virginia segment, the zone is moderately to shallowly east-dipping, with structures indicating thrusting of the Carolina terrane over the Milton terrane. Timing constraints on synkinematic plutons indicate that the shear zone is an early Alleghanian feature. The geometry, kinematics, and timing of the shear zone are compatible with the interpretation that the Hyco Lake and Virginia segments of the zone represent lateral and frontal ramps, respectively, in an overall Alleghanian thrust regime. Recognition of the shear zone in conjunction with geological, geophysical, and isotopic contrasts across the zone negates established views that the Milton rocks are a comformable, higher grade portion of the Carolina terrane. These contrasting features, instead, are remarkably similar to those found along the central Piedmont suture, the tectonic boundary between the Piedmont and Carolina zones from South Carolina to central North Carolina. We propose that the Hyco shear zone is the northern equivalent of this structure; thus, our new data on the Hyco shear zone have significant regional implications concerning the nature, timing, and kinematics of this zone boundary. DA - 1998/2// PY - 1998/2// DO - 10.2475/ajs.298.2.85 VL - 298 IS - 2 SP - 85-107 SN - 0002-9599 ER - TY - JOUR TI - The Columbia River Plume Study: Subtidal variability in the velocity and salinity fields AU - Hickey, BM AU - Pietrafesa, LJ AU - Jay, DA AU - Boicourt, WC T2 - JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS AB - A comprehensive study of the strongly wind driven midlatitude buoyant plume from the Columbia River, located on the U.S. west coast, demonstrates that the plume has two basic structures during the fall/winter season, namely, a thin (∼5–15 m), strongly stratified plume tending west to northwestward during periods of southward or light northward wind stress and a thicker (∼10–40 m), weakly stratified plume tending northward and hugging the coast during periods of stronger northward stress. The plume and its velocity field respond nearly instantaneously to changes in wind speed or direction, and the wind fluctuations have timescales of 2–10 days. Frictional wind‐driven currents cause the primarily unidirectional flow down the plume axis to veer to the right or left of the axis for northward or southward winds, respectively. Farther downstream, currents turn to parallel rather than cross salinity contours, consistent with a geostrophic balance. In particular, during periods when the plume is separated from the coast, currents tend to flow around the mound of fresher water. At distances exceeding about 20 km from the river mouth, the along‐shelf depth‐averaged flow over the inner to midshelf is linear, and depth‐averaged acceleration is governed to lowest order by the difference between surface and bottom stress alone. In this region, along‐shelf geostrophic buoyancy‐driven currents at ∼5 m (calculated from surface density) and along‐shelf geostrophic wind‐driven currents (computed from a depth‐averaged linear model) are comparable in magnitude (∼10–25 cm s −1 ). DA - 1998/5/15/ PY - 1998/5/15/ DO - 10.1029/97JC03290 VL - 103 IS - C5 SP - 10339-10368 ER - TY - JOUR TI - Sediment community structure around a whale skeleton in the deep Northeast Pacific: Macrofaunal, microbial and bioturbation effects AU - Smith, CR AU - Maybaum, HL AU - Baco, AR AU - Pope, RH AU - Carpenter, SD AU - Yager, PL AU - Macko, SA AU - Deming, JW T2 - DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY AB - Chemoautotrophic communities on lipid-rich whale skeletons are known from a total of 16 modern and fossil sites in the deep Pacific Ocean. While the attached fauna of modern whale bones has been studied, the impact of whale falls on surrounding sediment assemblages remains largely unevaluated. Using the research submersible Alvin, we sampled the sediment community at distances of 0, 0.5, 1, 2, 4, and ∼100 m from the lipid-rich skeleton of a 21 m balaenopterid on the 1240 m seafloor in Santa Catalina Basin. When sampled in 1988 and 1991, the skeleton had been on the seafloor for >4 yr and supported a large attached chemoautotrophic assemblage. Sedimentary organic content, microbial biomass and bacterial abundance were not significantly different near the skeleton than in background sediments, and pore-water sulfide concentrations were only modestly elevated (to ⩽20 μM) adjacent to the bones. The species composition of infaunal macrobenthos near the skeleton was similar to that in background sediments, providing little evidence of a specialized enrichment and/or sulfophilic assemblage. Nonetheless, macrofaunal abundance within 0.5 m of the skeleton was reduced by >40%, due to a decline in the paraonid polychaete Levinsenia oculata. The reduction in L. oculata (the community dominant) caused a sharp increase in rarefaction diversity near the skeleton. Bioturbation intensities, evaluated from 234Th profiles, were also dramatically reduced in sediments near the skeleton, as were rates of extracellular lipase activity. We postulate that reduced infaunal abundance and bioturbation near the skeleton resulted from the interference effects of vesicomyid clam-shell debris, and that the low bioturbation rates in turn limited extracellular lipase activity. We conclude that whale skeletons, and the remains of their associated chemoautotrophic assemblages, may physically impact nearby sediment communities for years after the organic and sulfide enrichment effects of whale falls have dissipated, yielding changes in infaunal diversity and bioturbation. DA - 1998/// PY - 1998/// DO - 10.1016/S0967-0645(97)00043-X VL - 45 IS - 1-3 SP - 335-364 SN - 0967-0645 ER - TY - JOUR TI - Precise timing, constraints on the kinematic development of the Hyco shear zone: Implications for the central Piedmont shear zone, southern Appalachian orogen AU - Wortman, GL AU - Samson, SD AU - Hibbard, JP T2 - AMERICAN JOURNAL OF SCIENCE AB - The recently discovered Hyco shear zone is a major tectonic boundary that separates terranes (Milton and Carolina) with sharply contrasting rock types, structural and metamorphic histories, and Nd isotopic compositions. Precise U-Pb zircon dates for an orthogneiss, a granitic gneiss, and synkinematic granites within the Hyco shear zone constrain the timing of motion, deformation, and metamorphism along this fundamental southern Appalachian structure. The synkinematic Yanceyville granite gneiss yields an upper intercept date of 335.4+ or -2.2 Ma. The syn-to late-synkinematic Kilgore granite crystallized at 327+ or -1.5 Ma. A Neoproterozoic hornblende gneiss from the northern portion of the zone yields a lower intercept date of 322.5+ or -2.7 Ma, which is interpreted to reflect the timing of deformation and metamorphism. The crystallization age of the Farmers Lake granite, a late-synkinematic intrusion, is 319.6+ or -0.7 Ma. These new dates document that the Hyco shear zone was active by mid-Mississippian time and that deformation and metamorphism were in their final stages by latest Mississippian time. The Hyco shear zone is considered the northernmost segment thus far recognized of the central Piedmont shear zone, an orogen-scale structure within the southern Appalachians that separates rocks of uncertain crustal affinity in the Piedmont zone from exotic, arc-related rocks of the Carolina zone. Comparison of the kinematic history of the Hyco shear zone with kinematic histories of more southerly segments of the central Piedmont shear zone indicates that Alleghanian deformation and metamorphism probably occurred contemporaneously along the entire shear zone. These observations are permissive of a model for the central Piedmont shear zone as an Alleghanian ductile shear zone that may extend from Georgia into the central Appalachians. DA - 1998/2// PY - 1998/2// DO - 10.2475/ajs.298.2.108 VL - 298 IS - 2 SP - 108-130 SN - 0002-9599 ER - TY - JOUR TI - Organism response to habitat patchiness: species and habitat-dependent recruitment of decapod crustaceans AU - Eggleston, DB AU - Etherington, LL AU - Elis, WE T2 - JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY AB - Habitat fragmentation from natural or anthropogenic causes is a common phenomenon in shallow water marine habitats such as seagrass beds and oyster reefs throughout the world. Thus, habitat- and scale-dependent information on how organisms perceive and respond to changes in the landscape is critical to efforts aimed at predicting the effects of habitat change on population abundance. In estuarine systems, seagrass is considered one of the predominant nursery habitats for numerous ecologically and commercially important species; however, recent information suggests that alternative habitats such as oyster reefs may also be important sites for settlement and refuge. We used artificial seagrass- and shell-filled plastic trays placed on unstructured seafloor in Back Sound, North Carolina, USA to examine the interactive effects of Experiment, Patch size and Habitat type upon recruitment success of four species of decapod crustaceans: the grass shrimps, Palaemonetes intermedius Holthuis, P. pugio Holthuis and P. vulgaris (Say), and the blue crab, Callinectes sapidus Rathbun. Regardless of habitat type, all species of grass shrimp and J1 blue crab responded to habitat patchiness at scales as small as 0.25 to 4 m−2, whereas larger J2–J4 blue crab did not. Mean densities of all three species of grass shrimp responded in a similar manner to patch size, with significantly higher densities in the smallest patch size (0.25 m−2) compared to larger patches (0.5 to 4 m−2). Conversely, mean densities of J1 blue crabs were significantly higher in the largest patch size (4 m−2) compared to smaller patches (0.25 to 1 m−2). There was a negative and significant relationship between the density of grass shrimp predators and density of J1 prey, and no relationship between potential fish predators and J1–J4 prey. Thus, patterns observed for J1 may be dependent upon predators and not habitat patch size. Both species demonstrated different responses to habitat type depending upon relative densities and body size. Mean densities of P. intermedius and P. vulgaris were higher in seagrass than oyster shell during Experiment 1 (May) when shrimp were relatively abundant, but did not differ between habitat types during Experiment 2 (October), when densities were reduced 10-fold. Conversely, densities of P. pugio did not differ between seagrass and oyster shell. Mean densities of J1 blue crab were similar between seagrass and oyster shell, but higher in seagrass than oyster shell for later juvenile stages (J2–J4). Thus, blue crabs may rely equally on seagrass and oyster reefs as an initial settlement and refuge habitat for early juveniles. Our study demonstrates that an organism's response to habitat patchiness is species-specific, and that for a given species, the response is further modified by animal density and body size. The patterns observed in this study further highlight the importance of scale-dependent responses by mobile organisms to complex benthic habitats. DA - 1998/5/1/ PY - 1998/5/1/ DO - 10.1016/S0022-0981(97)00154-8 VL - 223 IS - 1 SP - 111-132 SN - 1879-1697 KW - Callinectes sapidus KW - Crassostrea virginica KW - fragmentation KW - grass shrimp KW - habitat selection KW - palaemonidae KW - patchiness KW - recruitment KW - SLOSS KW - Zostera marina ER - TY - JOUR TI - Mesoscale analysis of a Carolina coastal front AU - Raman, S AU - Reddy, NC AU - Niyogi, DS T2 - BOUNDARY-LAYER METEOROLOGY DA - 1998/1// PY - 1998/1// DO - 10.1023/A:1000605030775 VL - 86 IS - 1 SP - 125-145 SN - 0006-8314 KW - GALE KW - coastal front KW - atmospheric boundary layer KW - Gulf Stream KW - mesoscale analysis KW - North Carolina ER - TY - JOUR TI - Mechanisms of cell regeneration, development, and propagation within a two-dimensional multicell storm AU - Lin, YL AU - Deal, RL AU - Kulie, MS T2 - JOURNAL OF THE ATMOSPHERIC SCIENCES AB - In this study, mechanisms of cell regeneration, development, and propagation within a two-dimensional multicell storm are investigated using a numerical cloud model. The cell regeneration is explained by the advection mechanism. The following processes occur periodically during cell regeneration: (i) Near the edge of the gust front, the gust front updraft is formed by low-level convergence ahead of the gust front near the surface. (ii) The upper portion of the gust front updraft grows by midlevel inflow since the gust front propagates faster than the basic wind. (iii) The growing cell tends to produce and is flanked by strong compensating downdrafts. The upstream downdraft tends to cut off the growing cell from the gust front updraft. It is found that the period of cell regeneration is inversely proportional to the midlevel, strong relative wind speed. This advection mechanism is different from that proposed by Yang and Houze, which views the rearward propagating cell as gravity waves generated by the quasi-steady updraft moving through the ambient flow. Cell development and propagation within a two-dimensional multicell storm may be described in terms of two distinctive modes: (i) a growing mode and (ii) a propagating mode. When a growing cell reaches its maximum intensity, it splits and then propagates downstream without amplification. The dynamics of cell development and propagation is explained here by critical level argument. For the growing mode there is growth because of a conditionally unstable environment leading to steering level propagation, while for the propagating mode there is no growth because of a more stable environment leading to propagation relative to the flow (i.e., absence of critical level). It is found that the phase relationship between w′ and θ′ (w′ and u′) in the growing mode is different from that in the propagating mode and can be explained by the dominance of latent heating in the thermodynamic equation. The propagating mode is dominated by horizontal advection. The propagating mode exhibits gravity wave properties and propagates faster than the growing mode. DA - 1998/5/15/ PY - 1998/5/15/ DO - 10.1175/1520-0469(1998)055<1867:MOCRDA>2.0.CO;2 VL - 55 IS - 10 SP - 1867-1886 SN - 0022-4928 ER - TY - JOUR TI - Mean profiles of moisture fluxes in snow-filled boundary layers AU - Kristovich, DAR AU - Braham, RR T2 - BOUNDARY-LAYER METEOROLOGY DA - 1998/5// PY - 1998/5// DO - 10.1023/A:1000836401204 VL - 87 IS - 2 SP - 195-215 SN - 0006-8314 KW - boundary layer KW - convective KW - lake-effect KW - moisture fluxes KW - precipitation ER - TY - JOUR TI - Influence of air mass history on black carbon concentrations and regional climate forcing in southeastern United States AU - Bahrmann, CP AU - Saxena, VK T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Atmospheric black carbon (BC) mass concentrations in the southeastern United States have been measured at a regionally representative site near Mount Mitchell, North Carolina (35°44′05″N, 82°17′15″W, 2038 m elevation), the highest peak in the eastern United States, during a 9 month period from June to October 1996 and March to June 1997. BC concentrations are measured by an aethalometer, which operates by measuring the attenuation of light through a sample. All measured BC concentrations are reported in terms of air mass histories determined from back trajectory analysis using the Hybrid Single‐Particle Lagrangian Integrated Trajectory (HY‐SPLIT) model. Air masses influencing the site have been classified as polluted, marine, and continental according to SO x and NO x . emission inventories. The average BC mass concentrations for each sector are 216.6±47.8 ng m −3 for polluted air masses, 65.6±23.5 ng m −3 for marine air masses, and 169.9±50.6 ng m −3 for continental air masses. A positive relationship between cloud condensation nuclei and BC concentrations suggest at times the BC measured at the site may be internally mixed. The average BC concentration found in cloud water is 74.2 μg kg −1 . Derived BC to sulfate mass ratios ranged from 0.01 to 0.06. DA - 1998/9/27/ PY - 1998/9/27/ DO - 10.1029/98JD02475 VL - 103 IS - D18 SP - 23153-23161 SN - 2169-897X ER - TY - JOUR TI - Evidence and mechanism of Hurricane Fran induced cooling in the Charleston trough AU - Xie, L AU - Pietrafesa, LJ AU - Bohm, E AU - Zhang, C AU - Li, X T2 - GEOPHYSICAL RESEARCH LETTERS AB - Evidence of enhanced sea surface cooling during and following the passage of Hurricane Fran in September 1996 over an oceanic depression located on the ocean margin offshore of Charleston, South Carolina (referred to as the Charleston Trough), [ Pietrafesa , 1983] is documented. Approximately 4C° of sea surface temperature (SST) reduction within the Charleston Trough following the passage of Hurricane Fran was estimated based on SST imagery from Advanced Very High Resolution Radiometer (AVHRR) on the NOAA‐14 polar orbiting satellite. Simulations using a three‐dimensional coastal ocean model indicate that the largest SST reduction occurred within the Charleston Trough. This SST reduction can be explained by oceanic mixing due to storm‐induced internal inertia‐gravity waves. DA - 1998/3/15/ PY - 1998/3/15/ DO - 10.1029/98GL00180 VL - 25 IS - 6 SP - 769-772 SN - 0094-8276 ER - TY - JOUR TI - Comparison of four different stomatal resistance schemes using FIFE data. Part II: Analysis of terrestrial biospheric-atmospheric interactions AU - Niyogi, DS AU - Raman, S AU - Alapaty, K T2 - JOURNAL OF APPLIED METEOROLOGY AB - Stomatal resistance (Rs) forms a pivotal component of the surface energy budget and of the terrestrial biosphere–atmosphere interactions. Using a statistical–graphical technique, the Rs-related interactions between different atmospheric and physiological variables are resolved explicitly from observations made during the First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment (FIFE). A similar analysis was undertaken for the Rs parameterization schemes, as used in the present models. Three physiological schemes (the Ball–Woodrow–Berry, Kim and Verma, and Jacobs) and one operational Jarvis-type scheme were evaluated in terms of their ability to replicate the terrestrial biosphere–atmosphere interactions. It was found that all of the Rs parameterization schemes have similar qualitative behavior for routine meteorological applications (without carbon assimilation). Compared to the observations, there was no significant difference found in employing either the relative humidity or the vapor pressure deficit as the humidity descriptor in the analysis. Overall, the relative humidity–based interactions were more linear than the vapor pressure deficit and hence could be considered more convenient in the scaling exercises. It was found that with high photosynthesis rates, all of the schemes had similar behavior. It was found with low assimilation rates, however, that the discrepancies and nonlinearity in the interactions, as well as the uncertainties, were exaggerated. Introduction of CO2 into the analysis created a different dimension to the problem. It was found that for CO2-based studies, the outcome had high uncertainty, as the interactions were nonlinear and the schemes could not converge onto a single interpretive scenario. This study highlights the secondary or indirect effects, and the interactions are crucial prior to evaluation of the climate and terrestrial biosphere–related changes even in the boundary layer perspective. Overall, it was found that direct and indirect effects could lead the system convergence toward different scenarios and have to be explicitly considered for atmospheric applications at all scales. DA - 1998/10// PY - 1998/10// DO - 10.1175/1520-0450(1998)037<1301:COFDSR>2.0.CO;2 VL - 37 IS - 10 SP - 1301-1320 SN - 0894-8763 ER - TY - JOUR TI - Analysis of ammonia and aerosol concentrations and deposition near the free troposphere at Mt. Mitchell, NC, USA AU - Aneja, VP AU - Murthy, AB AU - Battye, W AU - Battye, R AU - Benjey, WG T2 - ATMOSPHERIC ENVIRONMENT AB - Measurements of airborne (gaseous and aerosol), cloud water, and precipitation concentrations of ammonia (NH3) and ammonium (NH+4) compounds were made at Mt. Mitchell State Park (Mt. Gibbs, ∼2006 m MSL), North Carolina. Measurements were made from May to September during 1988 and 1989. An annular denuder system was used to determine gaseous NH3 and particulate NH+4 and nitrate (NO-3) compounds. Measurements of NH+4 in cloud and rain water samples were made during the same time period. Mean concentrations of gaseous NH3 were 0.62 μg m-3 for 1988 and 1.47 μg m-3 for 1989. Mean concentrations of fine particulate NH+4 were 1.24 μg m-3 for 1988 and 0.89 μg m-3 for 1989. The NH+4 concentrations in the cloud water were 214 and 147 μeq ℓ-1 for the 1988 and 1989 field seasons, respectively. The concentrations of NH+4 in precipitation were quite low compared to cloud ionic values in both 1988 and 1989 at 14 and 15 μeq ℓ-1, respectively. The estimated mean total deposition of NH+4 over the sampling period (5 months) of 1988 and 1989 was about 0.38 and 0.67 g N m-2 season-1, respectively. Cloud water interception contributed more nitrogen (∼70%) to the total deposition than combined wet (∼15%) and dry (∼15%) deposition. DA - 1998/2// PY - 1998/2// DO - 10.1016/S1352-2310(97)00236-7 VL - 32 IS - 3 SP - 353-358 SN - 1352-2310 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-0032006928&partnerID=MN8TOARS KW - ammonia KW - deposition KW - emissions KW - ambient monitoring KW - Mt. Mitchell KW - Smoky Mountains ER - TY - JOUR TI - The numerical simulation of an unbalanced jetlet and its role in the Palm Sunday 1994 tornado outbreak in Alabama and Georgia AU - Kaplan, ML AU - Lin, YL AU - Hamilton, DW AU - Rozumalski, RA T2 - MONTHLY WEATHER REVIEW AB - Meso-beta-scale numerical model simulations and observational data are synthesized in an effort to develop a multistage paradigm for use in forecasting tornadic convection in the southeastern United States. The case study to be utilized as an example of the multistage sequence of events is the Palm Sunday 1994 outbreak, which culminates with the development of an unbalanced mesoscale jet streak or jetlet that focuses a given region for significant values of low-level vertical wind shear, low-level confluence and vertical vorticity, midtropospheric cooling, and storm-relative helicity. The five-stage paradigm includes 1) the existence of a jet exit region accompanying a deep balanced thermally indirect circulation south of the outbreak and a return branch ageostrophic low-level southerly jet, both typically accompanying the subtropical jet stream and the leading edge of hot continental air; 2) the existence of a jet entrance region accompanying a deep balanced thermally direct circulation north of the outbreak and a return branch ageostrophic low-level northerly jet, both typically accompanying the polar jet stream and the leading edge of rain-cooled air; 3) the geostrophic adjustment of the wind in the southern jet to the emerging/intensifying mass field perturbation, that is, intensification of the cross-stream mesoscale pressure gradient force, caused by the juxtaposition of the rain-cooled air southeast of the polar front and hot air accompanying the continental front where evaporational cooling as well as surface heating merge resulting in unbalanced jetlet formation; 4) the low-level mass adjustment underneath the new mesoscale midtropospheric unbalanced jetlet induces a return branch low-level unbalanced jetlet as well as vertical motion patterns oriented along the stream; and 5) adiabatic cooling ahead of the unbalanced jetlet and sinking behind it accompanying the along-stream vertical circulation increases the intensity of downstream destabilization and upstream downward momentum fluxes, producing a favorable environment for severe convection. This new synoptic/dynamical overview assigns added importance to the subtropical jet, defines the continental air front, and also defines the unbalanced jetlet for use in predicting the presevere storm environment. DA - 1998/8// PY - 1998/8// DO - 10.1175/1520-0493(1998)126<2133:TNSOAU>2.0.CO;2 VL - 126 IS - 8 SP - 2133-2165 SN - 0027-0644 ER - TY - JOUR TI - Teleconnections between tropical Pacific sea surface temperature anomalies and North Carolina precipitation anomalies during El Nino events AU - Roswintiarti, O AU - Niyogi, DS AU - Raman, S T2 - GEOPHYSICAL RESEARCH LETTERS AB - Linear teleconnections of El Niño events and precipitation over a regional coastal land mass were analyzed. Two statistical techniques were used. First, the Empirical Orthogonal Function extracted major variances of the monthly tropical Pacific sea surface temperature anomalies and coastal North Carolina precipitation anomalies. Second, the Canonical Correlation Analysis calculated the linear combinations of the anomaly data sets that were highly correlated. The results show that El Niño‐related precipitation anomalies along the North Carolina coast were positive from November to May and negative between June and October consistent with large‐scale studies. Results indicate simple, linear statistical techniques can be effectively adopted to determine teleconnections on a local scale. DA - 1998/11/15/ PY - 1998/11/15/ DO - 10.1029/1998GL900121 VL - 25 IS - 22 SP - 4201-4204 SN - 0094-8276 ER - TY - JOUR TI - TVEBEX: Vegetation and surface energy balance experiment for the tropics AU - Raman, Sethu AU - Niyogi, D. S. AU - Prabhu, A. AU - Ameenullah, S. AU - Nagaraj, S. T. AU - Kumar, U. AU - Jayanna, S. T2 - Proceedings (Indian Academy of Sciences). Earth and Planetary Sciences AB - Surface features such as soil moisture and vegetation have a profound impact on the surface energy balance and the atmospheric boundary layer. To quantify this effect for a tropical location, a detailed field experiment, VEBEX, was designed and successfully executed in a tropical site at Bangalore, India. VEBEX was a joint experiment between the North Carolina State University, Indian Institute of Science (IISc), and the University of Agricultural Science (UAS) at Bangalore, India. Continuous surface meteorological measurements were taken over an entire crop period (pre-sowing to post-harvest). During different stages of the plant growth, intensive observations of surface turbulence, and measurements of physiological and soil moisture measurements were also conducted. The results obtained provide an insight into the unusually strong variability for the tropics. Interpretation of the observations and an overview of the analysis procedure and future research initiatives are also presented. DA - 1998/// PY - 1998/// DO - 10.1007/bf02842263 VL - 107 IS - 1 SP - 97-105 ER - TY - JOUR TI - Implications of harmful microalgae and heterotrophic dinoflagellates in management of sustainable marine fisheries AU - Burkholder, J. M. T2 - Ecological Applications DA - 1998/// PY - 1998/// DO - 10.2307/2641362 VL - 8 IS - 1 (suppl.) SP - S37-62 ER - TY - JOUR TI - Ground-based infrared solar spectroscopic measurements of carbon monoxide during 1994 Measurement of Air Pollution From Space flights AU - Pougatchev, NS AU - Jones, NB AU - Connor, BJ AU - Rinsland, CP AU - Becker, E AU - Coffey, MT AU - Connors, VS AU - Demoulin, P AU - Dzhola, AV AU - Fast, H AU - Grechko, EI AU - Hannigan, JW AU - Koike, M AU - Kondo, Y AU - Mahieu, E AU - Mankin, WG AU - Mittermeier, RL AU - Notholt, J AU - Reichle, HG AU - Sen, B AU - Steele, LP AU - Toon, GC AU - Yurganov, LN AU - Zander, R AU - Zhao, Y T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Results of the comparison of carbon monoxide ground‐based infrared solar spectroscopic measurements with data obtained during 1994 Measurement of Air Pollution From Space (MAPS) flights are presented. Spectroscopic measurements were performed correlatively with April and October MAPS flights by nine research groups from Belgium, Canada, Germany, Japan, New Zealand, Russia, and the United States. Characterization of the techniques and error analysis were performed. The role of the CO a priori profile used in the retrieval was estimated. In most cases an agreement between spectroscopic and MAPS data is within estimated MAPS accuracy of ±10%. DA - 1998/8/20/ PY - 1998/8/20/ DO - 10.1029/97JD02889 VL - 103 IS - D15 SP - 19317-19325 SN - 2169-897X ER - TY - JOUR TI - Biochemical relationships with the orientation of the autotrophic dinoflagellate Gymnodinium breve under nutrient replete conditions AU - Kamykowski, D AU - Milligan, EJ AU - Reed, RE 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 167:105-117 (1998) - doi:10.3354/meps167105 Biochemical relationships with the orientation of the autotrophic dinoflagellate Gymnodinium breve under nutrient replete conditions Daniel Kamykowski*, Edward J. Milligan, Robert E. Reed Department of Marine, Earth & Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695-8208, USA *E-mail: dan_kamykowski@ncsu.edu Swimming orientation in autotrophic marine dinoflagellates often follows a pattern attributed to positive phototaxis during the day and positive geotaxis at night. Exceptions that occur in field and laboratory observations most often describe ascents or descents that anticipate sunrise or sunset. These exceptions may originate in biochemical synthesis patterns that use sequential photosynthate (carbohydrate and lipid) production and dissolved nitrogen absorption for subsequent cell growth (RNA and protein) and division (DNA). Instantaneous biochemical state may influence orientation either through mechanical ballasting or through growth optimization that influences sensory-mediated responses to environmental cues. In the present mesocosm (150 cm length x 44 cm diameter) study, samples from a quantized (all cells divide together at approximately 3 d intervals) population of Gymnodinium breve Davis collected at the surface and mid-column support comparisons of diel orientation preferences and cellular biochemical states over a 3 d period. Up to 50% of the column population aggregates at the surface during the day, but this percentage decreases with time since cell division. Within a given day, G. breve exhibits continuous negative geotaxis associated with surface aggregation when the taxis is stronger and with dispersion through the water column when the taxis is weaker. Positive phototaxis helps maintain surface aggregation during the afternoon as negative geotaxis weakens. The surface cells exhibit only slightly lower concentrations of DNA and RNA, somewhat lower concentrations of protein and carbohydrate, and significantly lower concentrations of chlorophyll a and lipid, compared to the cells sampled from mid-column. The strength of the negative geotaxis of the mid-column cells negatively correlates with lipid concentration. These results support the case for a biochemical influence on orientation but require more experimental data to establish cause and effect. Dinoflagellate · Behavior · Biochemistry Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 167. Publication date: June 18, 1998 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1998 Inter-Research. DA - 1998/// PY - 1998/// DO - 10.3354/meps167105 VL - 167 SP - 105-117 J2 - Mar. Ecol. Prog. Ser. LA - en OP - SN - 0171-8630 1616-1599 UR - http://dx.doi.org/10.3354/meps167105 DB - Crossref KW - dinoflagellate KW - behavior KW - biochemistry ER - TY - JOUR TI - The structure and evolution of a numerically simulated high-precipitation supercell thunderstorm AU - Kulie, MS AU - Lin, YL T2 - MONTHLY WEATHER REVIEW AB - The structure and evolution of a high-precipitation (HP) supercell thunderstorm is investigated using a three-dimensional, nonhydrostatic, cloud-scale numerical model (TASS). The model is initialized with a sounding taken from a mesoscale modeling study of the environment that produced the 28 November 1988 Raleigh tornadic thunderstorm. TASS produces a long-lived convective system that compares favorably with the observed Raleigh tornadic thunderstorm. The simulated storm evolves from a multicell-type storm to a multiple-updraft supercell storm. The storm complex resembles a hybrid multicell-supercell thunderstorm and is consistent with the conceptual model of cool season strong dynamic HP supercells that are characterized by shallow mesocyclones. The origin of rotation in this type of storm is often in the lowest levels. Interactions between various cells in the simulated convective system are responsible for the transition to a supercellular structure. An intense low-level updraft core forms on the southwest flank of the simulated storm and moves over a region that is rich in vertical vorticity. The stretching of this preexisting vertical vorticity in the storm’s lowest levels is the most important vertical vorticity production mechanism during the initial stages of the main updraft’s development. Interactions with an extensive cold pool created by the storm complex are also important in producing vertical vorticity as the main updraft grows. Overall, the development of vorticity associated with the main updraft appears similar to nonsupercellular tornadic storms. However, classic supercell signatures are seen early in the simulation associated with other updrafts (e.g., formation of vortex couplet due to tilting of ambient horizontal vorticity, storm splitting, etc.) and are deemed important. In the storm’s supercell stage, rotation is sustained in the lowest levels of the storm despite large amounts of precipitation located near and within the main mesocyclone. Pulsating downdrafts periodically invigorate the storm and the gust front never occludes, thus allowing the main updraft to persist for a prolonged period of time. The storm’s intensity is also maintained by frequent updraft mergers. DA - 1998/8// PY - 1998/8// DO - 10.1175/1520-0493(1998)126<2090:TSAEOA>2.0.CO;2 VL - 126 IS - 8 SP - 2090-2116 SN - 0027-0644 ER - TY - JOUR TI - Surface mesoscale processes during the 1994 Palm Sunday tornado outbreak AU - Langmaid, AH AU - Riordan, AJ T2 - MONTHLY WEATHER REVIEW AB - The tornadic storms that developed in the 27 March 1994 Palm Sunday outbreak were confined to a narrow zone extending from central and northern Alabama to western North Carolina. Analysis of surface observations and soundings is used to examine the mesoscale environment of the region starting 14 h prior to storm development. The evolution of a shallow front that formed the northern boundary of the outbreak region is tied to several diabatic processes including evaporation of precipitation and differential solar heating. The resulting front was found to both limit severe convection and focus supercell development later in the day. During the night before the outbreak, as copious widespread precipitation fell into dry air, evaporation maintained a cold air pool north of the front. By contrast, moderate southerly flow provided warm, moist conditions to the south. Precipitation-enhanced cold air damming along the eastern slopes of the Appalachians also may have provided a source of cold air for subsequent frontogenesis over areas farther west. During the daylight hours, differential solar heating across the front further enhanced frontogenesis. Intensification of convection just prior to the first tornadoes was found to be associated with areas of breaks in the overcast near and upstream of tornadogenesis. Similarly, cells that intensified were moving over a surface that had been thoroughly moistened by previous rainfall. Supercells that intersected and moved along the frontal boundary maintained their tornadic strength for many hours, whereas storms that crossed the boundary disintegrated. Blockage of inflow by upstream storm cells may also have contributed to the rapid reduction of intensity of one of the tornadic cells. DA - 1998/8// PY - 1998/8// DO - 10.1175/1520-0493(1998)126<2117:SMPDTP>2.0.CO;2 VL - 126 IS - 8 SP - 2117-2132 SN - 0027-0644 ER - TY - JOUR TI - Jetlet formation from diabatic forcing with applications to the 1994 Palm Sunday tornado outbreak AU - Hamilton, DW AU - Lin, YL AU - Weglarz, RP AU - Kaplan, ML T2 - MONTHLY WEATHER REVIEW AB - The three-dimensional responses of simple stably stratified barotropic and baroclinic flows to prescribed diabatic forcing are investigated using a dry, hydrostatic, primitive equation numerical model (the North Carolina State University Geophysical Fluid Dynamics Model). A time-dependent diabatic forcing is utilized to isolate the effects of latent heat release in a midlatitude convective system. Examination of the mass-momentum adjustments to the diabatic forcing is performed with a focus on the development of an isolated midlevel wind maximum. The results of both cases suggest the formation of a midlevel wind maximum in the form of a perturbation meso-β-scale cyclone, which later propagates downstream as the heating is decreased. The scale of the perturbation cyclone remains at a sub-Rossby radius of deformation length scale. Therefore, the mass perturbations adjust to the wind perturbations as the mesocyclone propagates downstream. Transverse vertical circulations, which favor ascent on the right flank of the wind maximum, appear to be attributed to compensatory gravity wave motions, initially triggered by the thermal forcing, which laterally disperses as the heating is reduced. The simple model simulations are used to explain more complex results from a previous mesoscale modeling study (the Mesoscale Atmospheric Simulation System, MASS), in which it was hypothesized that an upstream mesoscale convective complex triggered a midlevel jetlet through geostrophic adjustment of the wind to the latent heat source. The MASS simulated jetlet attained a transverse vertical circulation that favored ascent on the right flank of the midlevel jetlet. The jetlet and accompanying transverse vertical circulations later propagated downstream aiding in the formation of the 27–28 March 1994 tornadic environment in Alabama and Georgia. DA - 1998/8// PY - 1998/8// DO - 10.1175/1520-0493(1998)126<2061:JFFDFW>2.0.CO;2 VL - 126 IS - 8 SP - 2061-2089 SN - 0027-0644 ER - TY - JOUR TI - Energy levels of light nuclei, A=20 AU - Tilley, DR AU - Cheves, CM AU - Kelley, CH AU - Raman, S AU - Weller, HR T2 - NUCLEAR PHYSICS A AB - Compilation of energy levels of A = 20 nuclei, with emphasis on the review of material leading to information about the structure of the A = 20 systems. DA - 1998/6/29/ PY - 1998/6/29/ DO - 10.1016/S0375-9474(98)00129-8 VL - 636 IS - 3 SP - 249-364 SN - 1873-1554 KW - compilation N-20, O-20, F-20, Ne-20, Na-20, Mg-20 KW - compiled, evaluated nuclear data ER - TY - JOUR TI - Baroclinically driven estuarine flow: A perturbation approach AU - Driscoll, EA AU - Janowitz, GS AU - Pietrafesa, LJ T2 - JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS AB - The residual circulation and density in a shallow estuary of constant depth and width and flowing at high Rayleigh number ( Ra ) and small internal Froude number ( Fr ), based on riverine flow ( U ∞ ) and the horizontal density variation, are studied. Criteria under which direct tidal effects on the residual flow can be neglected are established. The effects of varying the bottom boundary condition on the velocity field from free slip to no slip are examined using a linear bottom stress boundary condition. The governing equations are nondimensionalized, expanded in a power series in the small parameter, and the zeroth‐ and first‐order equations governing the density field are solved; these solutions yield the zeroth‐ and first‐order results for the velocity field. The equation governing the density field at lowest order is nonlinear and is solved numerically. The results show that for sufficiently large Ra , the mean transport of salt is balanced by baroclinic advection near the mouth and by horizontal turbulent transport farther upstream. For these large Ra the horizontal structure as well as the vertical structure of the flow is strongly affected by the bottom boundary condition with the salinity disturbances determined under the free‐slip condition extending twice as far upstream as the no‐slip results. For smaller Ra , though still large compared to 1, the mean transport is balanced by horizontal mixing throughout the system, and the bottom boundary condition does not affect the horizontal structure. The penetration distance of oceanic waters, with the internal Fr fixed, increases as Ra increases above 24, reaches a maximum upstream penetration distance of K h / U ∞ when Ra reaches 65, and decreases as Ra increases further. The ratio of entrained oceanic waters to riverine inflow is inversely proportional to the internal Fr to the 2/3 power for very large Ra and becomes proportional to Ra as the latter decreases. DA - 1998/11/15/ PY - 1998/11/15/ DO - 10.1029/98JC02376 VL - 103 IS - C12 SP - 27893-27903 ER - TY - JOUR TI - Atmospheric nitrogen compounds: Emissions, transport, transformation, deposition, and assessment AU - Aneja, V. P. AU - Murray, G. C. AU - Southerland, J. T2 - Environmental Manager DA - 1998/// PY - 1998/// IS - 1998 Apr. 1 SP - 22 ER - TY - JOUR TI - Teaching young researchers GIS: From wetlands to the Web AU - Queen, A. M. AU - Easterling, H. AU - Connors, V. S. T2 - Geo Info Systems DA - 1998/// PY - 1998/// VL - 8 IS - 3 SP - 38- ER - TY - JOUR TI - Sediment production on sediment-starved continental margins: The interrelationship between hardbottoms, sedimentological and benthic community processes, and storm dynamics AU - Riggs S. R., Ambrose W. G. AU - Cook J. W., Snyder S. W. AU - S.W., Snyder T2 - Journal of Sedimentary Research DA - 1998/// PY - 1998/// VL - 68 IS - 1 (pt A) SP - 155-168 ER - TY - PCOMM TI - Author's reply to ''The geostrophic velocity field in shallow water over topography'' by H. Charnock and P. Killworth AU - Hopkins, T. S. DA - 1998/// PY - 1998/// SP - 119-120 ER - TY - JOUR TI - Ground-based and airborne observations of carbon monoxide during NASA measurements of air pollution from satellite (MAPS) missions SRL-1 and SRL-2 AU - Doddridge, BG AU - Morales-Morales, R AU - Rhoads, KP AU - Merrill, JT AU - Novelli, PC AU - Dickerson, RR AU - Connors, VS AU - Reichle, HG T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Surface carbon monoxide (CO) data were acquired continuously at Heimaey, Iceland (63°24′N, 20° 18′W), Mace Head, Ireland (53° 19′N, 9°54′W), and Ragged Point, Barbados (13°15′N, 59°30′W), during April and October 1994, in support of Measurement of Air Pollution From Satellite (MAPS) Space Radar Laboratory (SRL) missions SRL‐1 and SRL‐2, respectively, measuring middle tropospheric CO from space. Observed median CO levels from the three surface sites during these two MAPS missions approximate the monthly median for 1994 and are mostly typical of data from prior years. For two of the sites, computed mission isentropic back‐trajectory ensemble probability fields are compared to seasonal (March‐May and September‐November) probability fields for 1994 and 1986–1995. Such comparisons help gauge the representativeness of (1) observed surface air quality at, and (2) isentropic flow to, these sites during the mission periods, in terms of intraseasonal and interannual variability. Results appear consistent with longer‐term flow climatological data and confirm the SRL‐1 and SRL‐2 mission periods are generally representative of the climatology applicable to these sites for the time of year. Lower free troposphere in situ CO data were acquired from an aircraft over the Maryland Eastern Shore on April 14 and October 3, 4, and 6. During the April flight a nearly linear gradient in CO with pressure from 1000–650 mbar of 225‐150 parts per billion by volume (ppbv) was observed. At 650 mbar, CO was quite steady around 150 ppbv; this value compares favorably with the MAPS CO data for the closest 5° ×; 5° grid box averaged April 13–15 of 105–120 ppbv. During SRL‐2 a three flight CO average of 125 ppbv observed at ∼725 mbar is in good agreement with the closest MAPS 5° × 5° grid box averaged October 3–7 of 90–105 ppbv. A layer of elevated CO at 845–740 mbar, most likely the result of synoptic‐scale transport, was observed during the October flights and seen to dissipate with time. The MAPS cloud‐filtered second‐by‐second CO data during concurrent shuttle overflights show temporal structure consistent with the in situ observations, indicating the MAPS weighting function may be capable of discerning features at lower altitudes than thought previously. DA - 1998/8/20/ PY - 1998/8/20/ DO - 10.1029/97JD01837 VL - 103 IS - D15 SP - 19305-19316 SN - 2169-8996 ER - TY - JOUR TI - Model reference adaptive control of distributed parameter systems AU - Bohm, M. AU - Demetriou, M. A. AU - Reich, S. AU - Rosen, I. G. T2 - SIAM Journal on Control and Optimization DA - 1998/// PY - 1998/// VL - 36 IS - 1 SP - 33-81 ER - TY - JOUR TI - A global nonhydrostatic semi-Lagrangian atmospheric model with orography AU - Qian, JH AU - Semazzi, FHM AU - Scroggs, JS T2 - MONTHLY WEATHER REVIEW AB - A global nonhydrostatic semi-implicit semi-Lagrangian (SISL) atmospheric model with orography has been developed. The height-based terrain-following σz coordinate of Gal-Chen and Somerville is used to incorporate the orography. A 3D vector form of the SISL formulation is proposed. It is based on the complete Navier–Stokes equations. The model is stable for large time steps of up to 1 h at horizontal/vertical resolution of 2.8125°/1200 m. Isolated bell-shaped mountain profiles and real orography are employed to evaluate the model performance. The sensitivity of the model with orography to the order of accuracy of the uncentering scheme, the reference temperature (T), and size of the time step are similar to that of the model without orography described in Semazzi et al. The authors find that for successful execution of the model, it is important that the orographic height Zs, the reference state mass variable (qs), and T satisfy the hydrostatic balance relationship in the terrain-following σz coordinate system. This formulation effectively controls the generation of unphysical orographic induced computational noise usually encountered in connection with semi-Lagrangian models. The global model used here is based on the complete dynamical Navier–Stokes equations, however, it is run at coarse resolutions, for which nonhydrostatic effects are negligible. In the future, when the computing resources permit, the model will be a valuable vehicle for investigating the role of multiple-scale interaction, including the effects of nonhydrostatic dynamics. DA - 1998/3// PY - 1998/3// DO - 10.1175/1520-0493(1998)126<0747:AGNSLA>2.0.CO;2 VL - 126 IS - 3 SP - 747-771 SN - 0027-0644 ER - TY - RPRT TI - Pfiesteria and pfiesteria-like dinoflagellates AU - Burkholder, J. M. A3 - Raleigh, NC: University of North Carolina Water Resources Research Institute C6 - 1998 Apr. 1 DA - 1998/// PY - 1998/// PB - Raleigh, NC: University of North Carolina Water Resources Research Institute ER - TY - JOUR TI - The summertime great plains low level jet and the effect of its origin on moisture transport AU - Wu, YH AU - Raman, S T2 - BOUNDARY-LAYER METEOROLOGY DA - 1998/9// PY - 1998/9// DO - 10.1023/A:1001518302649 VL - 88 IS - 3 SP - 445-466 SN - 0006-8314 KW - low level jets KW - moisture transport KW - nocturnal severe weather KW - the Great Plains ER - TY - JOUR TI - The effects of artificial reef vertical profile and hole diameter on fishes off South Carolina AU - Kellison, G. T. AU - Sedberry, G. R. T2 - Bulletin of Marine Science DA - 1998/// PY - 1998/// VL - 62 IS - 3 SP - 763-780 ER - TY - JOUR TI - MAPS - Preface AU - Reichle, HG AU - Connors, VS AU - Olson, J AU - Thompson, A T2 - JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES AB - Journal of Geophysical Research: AtmospheresVolume 103, Issue D15 p. 19283-19284 Free Access Preface [to special section on MAPS] Henry G. Reichle Jr., Henry G. Reichle Jr.Search for more papers by this authorVickie S. Connors, Vickie S. ConnorsSearch for more papers by this authorJennifer Olson, Jennifer OlsonSearch for more papers by this authorAnne Thompson Olson, Anne Thompson OlsonSearch for more papers by this author Henry G. Reichle Jr., Henry G. Reichle Jr.Search for more papers by this authorVickie S. Connors, Vickie S. ConnorsSearch for more papers by this authorJennifer Olson, Jennifer OlsonSearch for more papers by this authorAnne Thompson Olson, Anne Thompson OlsonSearch for more papers by this author First published: 01 August 1998 https://doi.org/10.1029/98JD01108Citations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. References Brasseur, G., S. Solomon, Aeronomy of the Middle Atmosphere 2nd ed., 452, D. Reidel, Norwell, Mass., 1986. Christopher, S. A., D. V. Kliche, R. M. Welch, andV. S. Connors, Satellite investigations of fire, smoke, and carbon monoxide during the April 1994 MAPS mission: Case studies over tropical Asia,J. Geophys. Res., 103(D15), 1998. Connors, V. S., P. C. Novelli, H. G. Reichle Jr., Space shuttle views changing carbon monoxide in lower atmosphere, Eos Trans. AGU, 77, 466, 1996. Crutzen, P. J., L. E. Heidt, J. P. Krasnec, W. H. Pollack, W. Seiler, Biomass burning as a source of atmospheric gases CO, H2, H2O, NO, CH3Cl, and COS, Nature, 282, 253, 1979. Doddridge, B. G., R. M. Morales, K. P. Rhoads, J. T. Merrill, P. C. Novelli, R. R. Dickerson, V. S. Connors, andH. G. Reichle Jr., Ground-based and airborne observations of carbon monoxide during NASA/MAPS missions SRL-1 and SRL-2.,J. Geophys. Res., 103(D15), 1998. Levy II, H., Normal atmosphere: Large radical and formaldehyde concentrations predicted, Science, 173, 141, 1971. Logan, J. A., J. Prather, S. C. Wofsy, M. B. McElroy, Tropospheric chemistry: A global perspective, J. Geophys. Res., 86, 7210, 1981. Mak, J. E., andC. A. M. Brenninkmeijer, Measurement of 13CO and C18O in the free troposphere,J. Geophys. Res., 103(D15), 1998. McConnell, J. C., M. B. McElroy, S. C. Wofsy, Natural sources of atmospheric CO, Nature, 233, 187, 1971. Novelli, P. C., et al.,An internally consistent set of globally distributed atmospheric carbon monoxide mixing ratios developed using results from an intercomparison of measurements,J. Geophys. Res., 103(D15), 1998. Pougatchev, N. S., et al.,Ground-based infrared solar spectroscopic measurements of carbon monoxide during 1994 MAPS flights,J. Geophys. Res., 103(D15), 1998. Reichle Jr., H. G., V. S. Connors, J. A. Holland, W. D. Hypes, H. A. Wallio, J. C. Casas, B. B. Gormsen, M. S. Saylor, W. D. Hesketh, Middle and upper tropospheric carbon monoxide mixing rations as measured by a satellite-borne remote sensor during November 1981, J. Geophys. Res., 91, 10865– 10887, 1986. Reichle Jr., H. G., V. S. Connors, J. A. Holland, R. T. Sherrill, H. A. Wallio, J. C. Casas, E. P. Condon, B. B. Gormsen, W. Seiler, The distribution of middle tropospheric carbon monoxide during early October 1984, J. Geophys. Res., 95, 9845– 9856, 1990. Robinson, E., R. C. Robbins, Sources, abundance and fate of gaseous atmospheric pollutants, supplemental reportRes. Proj. PR-6755Stanford Res. Inst., Menlo Park, Calif., 1969. Scheel, H. E., E.-G. Brunke, R. Sladkovic, andW. Seiler, In situ CO concentrations at the sites Zugspitze (47°N, 11°E) and Cape Point (34°S, 18°E) in April and October 1994,J. Geophys. Res., 103(D15), 1998. Sze, N. D., Anthropogenic CO emissions: Implications for the atmospheric CO-OH-CH4 cycle, Science, 195, 673– 674, 1977. Weinstock, B., Carbon monoxide: Residence time in the atmosphere, Science, 166, 224, 1969. Wofsy, S. C., J. C. McConnell, M. B. McElroy, Atmospheric CH4, CO, and CO2, J. Geophys. Res., 77, 4477, 1972. Yurganov, L. N., D. A. Jaffe, E. Pullman, andP. C. Novelli, Total column and surface densities of atmospheric carbon monoxide in Alaska, 1995,J. Geophys. Res., 103(D15), 1998. Zimmerman, P. R., R. B. Chatfield, J. Fishman, P. J. Crutzen, P. L. Hanst, Estimates on the production of CO and H2 from the oxidation of hydrocarbon emissions from vegetation, Geophys. Res. Lett., 5, 679, 1978. Citing Literature Volume103, IssueD1520 August 1998Pages 19283-19284 This article also appears in:MAPS ReferencesRelatedInformation DA - 1998/8/20/ PY - 1998/8/20/ DO - 10.1029/98JD01108 VL - 103 IS - D15 SP - 19283-19284 SN - 2169-8996 ER - TY - JOUR TI - A numerical modeling study of mesoscale cyclogenesis to the east of the Korean peninsula AU - Lee, TY AU - Park, YY AU - Lin, YL T2 - MONTHLY WEATHER REVIEW AB - Numerical simulations and the analysis of observational data are employed to understand the mesoscale cyclogenesis in a polar airstream that occurred over the sea to the east of the Korean peninsula on 28–29 January 1995. The observational analysis shows that a mesoscale low develops over the southeastern East Sea (Japan Sea) on 29 January 1995. Satellite imagery also indicates that a meso-β-scale vortex forms on the lee side of the northern Korean mountain complex (KMC), which is located in the northern Korean peninsula, and that a meso-α-scale cyclone develops over the southeastern East Sea at a later time. The mesoscale cyclone forms in the lower troposphere with strong baroclinicity and cyclonic circulation under the influence of an upper-level synoptic-scale cold vortex. Numerical simulation has captured major features of the observed cyclogenesis very well. The cyclogenesis occurs in a progressive manner. Basically, four distinctive stages of the cyclogenesis are identified. 1) First, a surface pressure trough forms on the lee side of the KMC under a northwesterly synoptic-scale flow that is deflected anticyclonically over the KMC. 2) Second, the lee trough deepens further into a strong convergence zone and a meso-β-scale vortex. 3) Next, the meso-β-scale vortex develops into a meso-α-scale vortex as the vortex and the trough begin to move southeastward from the lee of the KMC. 4) Finally, the surface trough deepens into a closed low and the meso-α-scale vortex becomes collocated with this deepening surface low to form a meso-α-scale cyclone over the southeastern East Sea. Several sensitivity experiments are performed to isolate the effects of a topography, warmer sea surface, diurnal thermal forcing, and latent heat release. During stages 1 and 2, it is found that the KMC and low-level baroclinicity are responsible for generating the strong lee trough and vortex. During stage 3, the development of the meso-α-scale vortex is brought on by the tilting of horizontal vorticity and vertical stretching in a synoptic-scale cyclonic circulation. In the final stage, the condensational heating plays the key role for the development of the meso-α-scale cyclone under the influence of an upper-level synoptic-scale cold vortex. The presence of the warm sea surface is found to be a necessary condition for the development of a polar air convergence zone and the mesoscale cyclone. It is also found that the low-level baroclinicity is essential for the present case of mesoscale cyclogenesis. DA - 1998/9// PY - 1998/9// DO - 10.1175/1520-0493(1998)126<2305:ANMSOM>2.0.CO;2 VL - 126 IS - 9 SP - 2305-2329 SN - 0027-0644 ER - TY - JOUR TI - The thermoregulatory functions of the Triceratops frill and horns: Heat flow measured with oxygen isotopes AU - Barrick, RE AU - Stoskopf, MK AU - Marcot, JD AU - Russell, DA AU - Showers, WJ T2 - JOURNAL OF VERTEBRATE PALEONTOLOGY AB - ABSTRACT Variability of body temperature within fossil vertebrates can be measured by the oxygen isotopie composition of bone phosphate (δp). Intrabone and interbone δp variations indicate heat flow within an individual and can be used to establish thermoregulatory strategies such as homeothermy and regional heterothermy. This method is applied to an individual Triceratops skeleton where the results suggest very high and uniform heat flow through the parietal frill, maintaining mean frill temperatures between 0–4°C below the body core. Heat flow to the postorbital horn-core is much more variable. The frill and horn cores of Triceratops were used as thermoregulatory structures with the horn cores interpreted as being especially important in the stabilization of brain temperatures at extreme ambient temperatures and the frill serving a more consistent role in body temperature regulation. DA - 1998/12// PY - 1998/12// DO - 10.1080/02724634.1998.10011103 VL - 18 IS - 4 SP - 746-750 SN - 0272-4634 ER -