TY - CONF TI - Carcavelos beach sedimentary dynamics C2 - 2006/// C3 - 5th Geophysics and Geodesy Portuguese- Spanish Meeting DA - 2006/// ER - TY - JOUR TI - Sea Surface Temperature Patterns on the West Florida Shelf Using Growing Hierarchical Self-Organizing Maps AU - Liu, Yonggang AU - Weisberg, Robert H. AU - He, Ruoying T2 - Journal of Atmospheric and Oceanic Technology AB - Abstract Neural network analyses based on the self-organizing map (SOM) and the growing hierarchical self-organizing map (GHSOM) are used to examine patterns of the sea surface temperature (SST) variability on the West Florida Shelf from time series of daily SST maps from 1998 to 2002. Four characteristic SST patterns are extracted in the first-layer GHSOM array: winter and summer season patterns, and two transitional patterns. Three of them are further expanded in the second layer, yielding more detailed structures in these seasons. The winter pattern is one of low SST, with isotherms aligned approximately along isobaths. The summer pattern is one of high SST distributed in a horizontally uniform manner. The spring transition includes a midshelf cold tongue. Similar analyses performed on SST anomaly data provide further details of these seasonally varying patterns. It is demonstrated that the GHSOM analysis is more effective in extracting the inherent SST patterns than the widely used EOF method. The underlying patterns in a dataset can be visualized in the SOM array in the same form as the original data, while they can only be expressed in anomaly form in the EOF analysis. Some important features, such as asymmetric SST anomaly patterns of winter/summer and cold/warm tongues, can be revealed by the SOM array but cannot be identified in the lowest mode EOF patterns. Also, unlike the EOF or SOM techniques, the hierarchical structure in the input data can be extracted by the GHSOM analysis. DA - 2006/2// PY - 2006/2// DO - 10.1175/jtech1848.1 VL - 23 IS - 2 SP - 325-338 ER - TY - JOUR TI - Hindcast Experiment of a Nested a Baroclinic West Florida Shelf Model AU - Barth, Alexander AU - Alvera-Azcarate, Aida AU - Weisberg, Robert H AU - He, Ruoying DA - 2006/// PY - 2006/// ER - TY - JOUR TI - Mapped fields of surface geostrophic currents based on altimetry, and fields of sea surface winds, cloud-free sea surface temperature and chlorophyll concentration using monovariate OI and a multivariate EOF technique AU - Alvera Azcarate, Aı̈da AU - Barth, Alexander AU - Helber, RW AU - He, R AU - Weisberg, RH DA - 2006/// PY - 2006/// ER - TY - JOUR TI - Barotropic tides on the southeast New England shelf: A view from a hybrid data assimilative modeling approach AU - He, Ruoying AU - Wilkin, John L. T2 - Journal of Geophysical Research AB - A high‐resolution hybrid data assimilative (DA) modeling system is used to study barotropic tides and tidal dynamics on the southeast New England shelf. In situ observations include tidal harmonics of 5 major tidal constituents [M 2 , S 2 , N 2 , O 1 , and K 1 ] analyzed from coastal sea level and bottom pressure gauges. The DA system consists of both forward and inverse models. The former is the three‐dimensional, finite difference, nonlinear Regional Ocean Modeling System (ROMS). The latter is a three‐dimensional linearized, frequency domain, finite element model TRUXTON. The DA system assimilates in situ observations via the inversion for the barotropic tidal open boundary conditions (OBCs). Model skill is evaluated by comparing the misfits between the observed and modeled tidal harmonics. The assimilation scheme is found effective and efficient in correcting the tidal OBCs, which in turn improve ROMS tidal solutions. Up to 50% decreases of model/data misfits are achieved after inverse data assimilation. Co‐amplitude and co‐phase maps and tidal current ellipses for each of 5 tidal constituents are generated, revealing complex tidal variability in this transition region between the tidally amplified Gulf of Maine in the northeast and the tidally much less energetic Middle Atlantic Bight in the southwest. Detailed examinations on the residual circulation, energetics, and momentum balances of the M 2 tide reveal the key roles of the unique bottom bathymetry of Nantucket Shoals and the complex coastal geometry in affecting the regional tidal dynamics. DA - 2006/// PY - 2006/// DO - 10.1029/2005jc003254 VL - 111 IS - C8 ER - TY - THES TI - Multidisciplinary approach for the Seismotectonic study of the Tagus Lower Valley DA - 2006/11/6/ PY - 2006/11/6/ UR - http://repositorio.ul.pt/ ER - TY - JOUR TI - Stratosphere-troposphere coupling during spring onset AU - Black, Robert X. AU - McDaniel, Brent A. AU - Robinson, Walter A. T2 - Journal of Climate AB - Abstract The authors perform an observational study of the relation between stratospheric final warmings (SFWs) and the boreal extratropical circulation. SFW events are found to provide a strong organizing influence upon the large-scale circulation of the stratosphere and troposphere during the period of spring onset. In contrast to the climatological seasonal cycle, SFW events noticeably sharpen the annual weakening of high-latitude circumpolar westerlies in both the stratosphere and troposphere. A coherent pattern of significant westerly (easterly) zonal wind anomalies is observed to extend from the stratosphere to the earth’s surface at high latitudes prior to (after) SFW events, coinciding with the polar vortex breakdown. This evolution is associated with a bidirectional dynamical coupling of the stratosphere–troposphere system in which tropospheric low-frequency waves induce annular stratospheric circulation anomalies, which in turn, are followed by annular tropospheric circulation anomalies. The regional tropospheric manifestation of SFW events consists of a North Atlantic Oscillation (NAO)-like phase transition in the near-surface geopotential height field, with height rises over polar latitudes and height falls over the northeast North Atlantic. This lower-tropospheric change pattern is distinct from the climatological seasonal cycle, which closely follows seasonal trends in thermal forcing at the lower boundary. Although broadly similar, the tropospheric anomaly patterns identified in the study do not precisely correspond to the canonical northern annular mode (NAM) and NAO patterns as the primary anomaly centers are retracted northward toward the pole. The results here imply that (i) high-latitude climate may be particularly sensitive to long-term trends in the annual cycle of the stratospheric polar vortex and (ii) improvements in the understanding and simulation of SFW events may benefit medium-range forecasts of spring onset in the extratropics. DA - 2006/// PY - 2006/// DO - 10.1175/JCLI3907.1 VL - 19 IS - 19 SP - 4891-4901 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000241159500010&KeyUID=WOS:000241159500010 ER - TY - JOUR TI - The physical basis for predicting Atlantic sector seasonal-to-interannual climate variability AU - Kushnir, Y. AU - Robinson, W.A. AU - Chang, P. AU - Robertson, A.W. T2 - Journal of Climate AB - Abstract This paper reviews the observational and theoretical basis for the prediction of seasonal-to-interannual (S/I) climate variability in the Atlantic sector. The emphasis is on the large-scale picture rather than on regional details. The paper is divided into two main parts: a discussion of the predictability of the North Atlantic Oscillation (NAO)—the dominant pattern of variability in the North Atlantic—and a review of the tropical Atlantic prediction problem. The remote effects of El Niño are also mentioned as an important factor in Atlantic climate variability. Only a brief discussion is provided on the subject of South Atlantic climate predictability. Because of its chaotic dynamical nature, the NAO and its related rainfall and temperature variability, while highly significant over Europe and North America, are largely unpredictable. This also affects the predictive skill over the tropical Atlantic, because the NAO interferes with the remote influence of El Niño. That said, there appears to be an insufficiently understood, marginal signal in the NAO behavior that may be predictable and thus useful to certain end users. It is manifested in the deviation of the NAO temporal behavior from first-order autoregressive behavior. Tropical Atlantic climate variability centers on the sensitivity of the marine ITCZ to remote forcing from the equatorial Pacific and interactions with underlying sea surface temperature (SST) variability. Both mechanisms are potentially predictable—that is, given the underlying SSTs and the strength of El Niño, one could determine with a high degree of skill the anomalies in ITCZ position and intensity. However, local SSTs are easily affected by largely unpredictable North and South Atlantic phenomena, such as the NAO. In addition, the local ocean–atmosphere coupling in the Atlantic acts on relatively short time scales. Thus, in reality the level of skill indicated by forced model simulations are difficult to achieve. The use of coupled models may improve the prospects of tropical Atlantic prediction. DA - 2006/// PY - 2006/// DO - 10.1175/JCLI3943.1 VL - 19 IS - 23 SP - 5949-5970 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33846183775&partnerID=MN8TOARS ER - TY - JOUR TI - On the self-maintenance of midlatitude jets AU - Robinson, Walter A. T2 - Journal of the Atmospheric Sciences AB - Abstract In this paper an atmospheric jet is considered self-maintaining if the overall effect of baroclinic eddies is to preserve or enhance its westerly shear with height. Observations suggest that the wintertime jets in Earth’s atmosphere are self-maintaining. This has implications for the intrinsic variability of these jets—the annular modes—and for how the extratropics respond to tropical warming. The theory of quasigeostrophic eddy–zonal flow interactions is employed to determine how a jet can be self-maintaining. Whether or not a jet is self-maintaining is found to depend sensitively on the meridional distribution of the absorption of wave activity. The eddy driving of the jet in a simple two-level model of the global circulation is examined. It is found that, with approximately wintertime settings of parameters (a radiative equilibrium equator–pole temperature contrast of 60 K), the midlatitude jets in this model are self-maintaining. The jet is not self-maintaining, however, when the radiative equilibrium equator-to-pole temperature contrast is reduced below a critical value (∼24 K temperature contrast). Eddy amplitudes are also greatly reduced, in this case. The transition to a self-maintaining jet, as the radiative equilibrium temperature contrast is increased, suggests a set of feedback mechanisms that involve the strength of the baroclinicity in the jet center and where baroclinic eddies are absorbed in the subtropics. A barotropic eastward force applied to the model Tropics causes a poleward shift in the latitudes of greatest eddy absorption and induces a transition from a non-self-maintaining to a self-maintaining jet. Self-maintaining behavior ultimately disappears, as the equator–pole thermal contrast, and thus the eddies, are strengthened. The flow is then highly disturbed and no longer dominated by wavelike baroclinic eddies. DA - 2006/// PY - 2006/// DO - 10.1175/JAS3732.1 VL - 63 IS - 8 SP - 2109-2122 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000239599800010&KeyUID=WOS:000239599800010 ER - TY - JOUR TI - Effects of Ekman transport on the NAO response to a tropical Atlantic SST anomaly AU - Peng, Shiling AU - Robinson, Walter A. AU - Li, Shuanglin AU - Alexander, Michael A. T2 - Journal of Climate AB - Abstract A recent study showed that a tropical Atlantic sea surface temperature (SST) anomaly induces a significant coupled response in late winter [February–April (FMA)] in a coupled model, in which an atmospheric general circulation model is coupled to a slab mixed layer ocean model (AGCM_ML). The coupled response comprises a dipole in the geopotential height, like the North Atlantic Oscillation (NAO), and a North Atlantic tripole in the SST. The simulated NAO response developed 1 or 2 months later in the model than in observations. To determine the possible effects of Ekman heat transport on the development of the coupled response to the tropical forcing, an extended coupled model (AGCM_EML), including Ekman transport in the slab mixed layer ocean, is now used. Large ensembles of AGCM_EML experiments are performed, parallel to the previous AGCM_ML experiments, with the model forced by the same tropical Atlantic SST anomaly over the boreal winter months (September–April). The inclusion of Ekman heat transport is found to result in an earlier development of the coupled NAO–SST tripole response in the AGCM_EML, compared to that in the AGCM_ML. The mutual reinforcement between the anomalous Ekman transport and the surface heat flux causes the tropical forcing to induce an extratropical SST response in November–January (NDJ) in the AGCM_EML that is twice as strong as that in the AGCM_ML. The feedback of this stronger extratropical SST response on the atmosphere in turn drives the development of the NAO response in NDJ. In FMA, the sign of the anomalous surface heat flux is reversed in the Gulf Stream region such that it opposes the anomalous Ekman transport. The resulting equilibrium NAO response in the AGCM_EML is similar to that in the AGCM_ML, but it is reached 1–2 months sooner in the AGCM_EML. Hence, the presence of Ekman transport causes a seasonal shift in the evolution of the coupled response. The faster development of the NAO response in the AGCM_EML suggests that tropical Atlantic SST anomalies should be able to influence the NAO, in nature, on the seasonal time scale, and that efficient interactions with the extratropical ocean play a significant role in determining the coupled response. DA - 2006/// PY - 2006/// DO - 10.1175/JCLI3910.1 VL - 19 IS - 19 SP - 4803-4818 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000241159500005&KeyUID=WOS:000241159500005 ER - TY - JOUR TI - A comprehensive performance evaluation of MM5-CMAQ for the Summer 1999 Southern Oxidants Study episode—Part II: Gas and aerosol predictions AU - Zhang, Yang AU - Liu, Ping AU - Queen, Ashley AU - Misenis, Chris AU - Pun, Betty AU - Seigneur, Christian AU - Wu, Shiang-Yuh T2 - Atmospheric Environment AB - Gas and aerosol predictions from CMAQ simulations with horizontal grid spacings of 8- and 32-km are evaluated against available observations from CASTNet, IMPROVE, AIRS-AQS, SOS99/SOS99NASH, SEARCH, and ARIES for the southeastern US for the period of 1–10 July 1999. The predictions evaluated in this work include mixing ratios of O3 (hourly, maximum 1-h, and 8-h average), NOx, HNO3, NOy, and mass concentrations of PM10, PM2.5, and PM2.5 components. Our evaluation has shown that CMAQ tends to underpredict maximum 1-h O3 mixing ratios on high O3 days at some sites. It overpredicts the maximum and minimum hourly O3 mixing ratios for most low O3 days, the daytime and nighttime hourly, and the maximum 8-h average O3 mixing ratios on most days at all sites. The model performance for hourly O3 mixing ratios generally meets EPA's criteria but deteriorates for maximum 1- and 8-h average O3 mixing ratios. CMAQ underpredicts the mass concentrations of PM10, PM2.5, and PM2.5 composition and fails to reproduce their temporal variations (except for sulfate). Largest underpredictions occur for organic matter (OM2.5) and nitrate2.5 among all PM components. These underpredictions and overpredictions may be caused by inaccurate meteorological predictions (e.g., the PBL height, wind speed/direction, vertical mixing, temperature, and relative humidity) and boundary conditions for chemical species (e.g., O3), underestimation in emissions (e.g., NOx, NH3, and primary OM), as well as uncertainties in model assumptions and treatments in aerosol chemistry and microphysics. DA - 2006/8// PY - 2006/8// DO - 10.1016/j.atmosenv.2005.12.048 VL - 40 IS - 26 SP - 4839-4855 J2 - Atmospheric Environment LA - en OP - SN - 1352-2310 UR - http://dx.doi.org/10.1016/j.atmosenv.2005.12.048 DB - Crossref KW - model evaluation KW - CMAQ KW - SOS KW - PM2.5 KW - ozone ER - TY - JOUR TI - A comprehensive performance evaluation of MM5-CMAQ for the summer 1999 southern oxidants study episode, Part III: Diagnostic and mechanistic evaluations AU - Zhang, Yang AU - Liu, Ping AU - Pun, Betty AU - Seigneur, Christian T2 - Atmospheric Environment AB - As Part III of a comprehensive evaluation of CMAQ for the summer 1999 Southern Oxidants Study episode, the observed number (N), volume (V), surface area (S), and size distributions of accumulation-mode particles during the Aerosol Research Inhalation Epidemiological Study (ARIES) are used to evaluate CMAQ's capability in reproducing PM size distributions. CMAQ underpredicts V, S, and geometric number mean diameter (by a factor of 1.24–1.54), and overpredicts N, geometric standard deviation, and geometric volume mean diameter (by a factor of 1.46–2.2) on most days. In addition to inaccurate meteorology and emissions, insufficient condensational growth of PM and uncertainty in the initial size distribution may contribute to the underpredictions in V and S. An overestimation of the PM number emission rates (by a factor of 3–5.3) and several other model assumptions/treatments may contribute to the PM number overpredictions. Among the factors that we studied, the floor value of Kzz, the boundary conditions (BCONs) of O3, the emissions of gaseous precursors such as NOx and NH3 and primary PM species such as POM, and the assumed initial PM size distribution and emission fractions have been identified to be the most influential factors that affect the overall model performance. Sensitivity simulations with a floor value of Kzz of 0.1 cm2 s−1, adjusted emissions of NOx, NH3, and POM, and adjusted initial PM size distribution and emission fractions provide moderate-to-significant improvements. Further investigation into the uncertainties/deficiencies in model treatments for PM such as gas-to-particle mass transfer will identify additional causes for discrepancies between observations and predictions. DA - 2006/8// PY - 2006/8// DO - 10.1016/j.atmosenv.2005.12.046 VL - 40 IS - 26 SP - 4856-4873 J2 - Atmospheric Environment LA - en OP - SN - 1352-2310 UR - http://dx.doi.org/10.1016/j.atmosenv.2005.12.046 DB - Crossref KW - CMAQ KW - SOS KW - sensitivity study KW - ozone KW - PM2.5 KW - particle size distribution ER - TY - JOUR TI - Coherence between solar activity and the East Asian winter monsoon variability in the past 8000 years from Yangtze River-derived mud in the East China Sea AU - Xiao, Shangbin AU - Li, Anchun AU - Liu, J. Paul AU - Chen, Muhong AU - Xie, Qiang AU - Jiang, Fuqing AU - Li, Tiegang AU - Xiang, Rong AU - Chen, Zhong T2 - Palaeogeography, Palaeoclimatology, Palaeoecology AB - AMS14C dating and grain-size analysis for Core PC-6, located in the middle of a mud area on the inner shelf of the East China Sea (ECS), were used to rebuild the Holocene history of the East Asian winter monsoon (EAWM). The 7.5-m core recorded the history of environmental changes during the postglacial transgression. The core’s mud section (the upper 450 cm) has been formed mainly by suspended sediment delivered from the Yangtze River mouth by the ECS Winter Coastal Current (ECSWCC) since 7.6 kyr BP. Using a mathematical method called “grain size vs. standard deviation”, we can divide the Core PC-6’s grain-size distribution into two populations at about 28 μm. The fine population (< 28 μm) is considered to be transported by the ECSWCC as suspended loads. Content of the fine population changes little and represents a stable sedimentary environment in accord with the present situation. Thus, variation of mean grain-size from the fine population would reflect the strength of ECSWCC, which is mainly controlled by the East Asian winter monsoon. Abrupt increasing mean grain size in the mud section is inferred to be transported by sudden strengthened ECSWCC, which was caused by the strengthened EAWM. Thus, the high resolution mean grain-size variation might serve as a proxy for reconstruction of the EAWM. A good correlation between sunspot change and the mean grain-size of suspended fine population suggests that one of the primary controls on centennial- to decadal-scale changes of the EAWM in the past 8 ka is the variations of sun irradiance, i.e., the EAWM will increase in intensity when the number of sunspots decreases. Spectral analyses of the mean grain-size time series of Core PC-6 show statistically significant periodicities centering on 2463, 1368, 128, 106, 100, 88-91, 76-78, and 70-72 years. The EAWM and the East Asian summer monsoon (EASM) agree with each other well on these cycles, and the East Asian Monsoon (EAM) and the Indian Monsoon also share in concurrent cycles in Holocene, which are in accord with the changes of the sun irradiance. DA - 2006/8// PY - 2006/8// DO - 10.1016/j.palaeo.2005.12.003 VL - 237 IS - 2-4 SP - 293-304 J2 - Palaeogeography, Palaeoclimatology, Palaeoecology LA - en OP - SN - 0031-0182 UR - http://dx.doi.org/10.1016/j.palaeo.2005.12.003 DB - Crossref KW - solar irradiance KW - East Asian monsoon KW - Holocene KW - spectral analyses KW - East China sea KW - grain-size ER - TY - JOUR TI - Considering ecological formulations for estimating deposition velocity in air quality models AU - Niyogi, D. AU - Alapaty, K. AU - Phillips, S. AU - Aneja, V.P. T2 - International Journal of Global Environmental Issues AB - A dry deposition modelling approach that includes surface feedback through photosynthesis relationships was recently developed. A canopy photosynthesis model is dynamically coupled to an atmospheric model with prognostic soil hydrology and surface energy balance. The effective surface resistance is calculated for a realistic and fully interactive estimation of gaseous deposition velocity (Vd). The model was able to correctly estimate observed ozone Vd over agricultural fields. The same model was tested for its ability to simulate ammonia Vd near an animal agricultural facility. The scheme did not reproduce the bi-directional exchange and had a much smaller range as compared to observations. The model was modified to include a simple ammonia compensation point formulation and the results were much closer to the observations. Study concludes that ecological approaches with default parameterisation and biophysical constants are convenient and effective in estimating Vd for air quality models. DA - 2006/// PY - 2006/// DO - 10.1504/ijgenvi.2006.010158 VL - 6 IS - 2-3 SP - 270-284 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33746257492&partnerID=MN8TOARS ER - TY - JOUR TI - A preliminary review of gas-to-particle conversion monitoring and modelling efforts in the USA AU - Baek, B.-H. AU - Koziel, J.A. AU - Aneja, V.P. T2 - International Journal of Global Environmental Issues AB - Ammonia and inorganic acid gases emitted from livestock and poultry operations, manure treatment, handling and application can affect air quality by the formation of secondary fine particles. The process of gas-to-particle conversion (GTPC) of relatively short-lived gaseous ammonia to more persistent fine particles can affect local and regional air quality far away from the agricultural sources. This study focused on understanding the phenomenon and related problems of the GTPC process between ammonia, acid gases and fine particles in the atmosphere. We discuss the knowledge of PM measurement technologies with their uncertainties and introduce the most recent aerosol models available developed to simulate the equilibrium partitioning of inorganic compounds between the gas and aerosol phases. We discuss the development and evaluate progress on ambient PM research using 3D air quality models and demonstrate the importance of the GTPC process concerning the contribution of ammonia on fine PM formation in agricultural areas. DA - 2006/// PY - 2006/// DO - 10.1504/ijgenvi.2006.010155 VL - 6 IS - 2-3 SP - 204-230 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33746241980&partnerID=MN8TOARS ER - TY - JOUR TI - Temporal variability and case study of high O3 episodes in two southeastern US national parks AU - Tong, D.Q. AU - Aneja, V.P. AU - Arya, S.P. AU - Ray, J.D. T2 - International Journal of Global Environmental Issues AB - Despite a decreasing trend nationwide, eight-hour O3 concentrations in 25 of US national parks have increased by 8% during last decade. This study presents a 13-year observation of high O3 at the Great Smoky Mountains (GRSM) and Mammoth Cave (MACA) national parks, both among the 25 impacted parks. Although there is no monotonic increase, the later half witnessed three-fold exceedances than the former. O3 exceedances occurred most frequently in June at MACA, and in August or September at GRSM. High O3 episodes at MACA occurred during daytime or early evening, but exceedances at GRSM can be found in any hour. Air masses with high O3 at GRSM came from all directions, whereas those at MACA are predominantly from the southwest. Case studies show that high O3 episodes at MACA are developed under clear sky, high temperature, low humidity, and weak winds traveling in a uniform anti-cyclonal pathway. DA - 2006/// PY - 2006/// DO - 10.1504/ijgenvi.2006.010159 VL - 6 IS - 2-3 SP - 173-188 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33746257498&partnerID=MN8TOARS ER - TY - JOUR TI - Vertical distribution of VOCs and ozone observed in suburban North Carolina AU - Das, M. AU - Aneja, V.P. AU - Kang, D. T2 - International Journal of Global Environmental Issues AB - As a continuing effort by the State of North Carolina to develop a State Implementation Plan for ozone control in the Raleigh Metropolitan Statistical Area, vertical measurements of C2–C10 hydrocarbons and ozone are made on a 610 meter multi-communications tower. Results signify that both long-range transport from fossil fuel combustion, petroleum exploration, petroleum refineries, and geogenic natural gas and local emissions from surface coating and paper production are the major sources of anthropogenic organic compounds at this location. Vertical distributions of various compounds are examined with respect to the relative abundance as well as reactivity to study the role of NMHCs in ozone production. When the concentrations of NMHCs are lower than some threshold value (60 ppbC), ozone concentrations increase with the increase of NMHC concentrations; but when NMHC concentrations are higher than 60 ppbC, ozone concentrations decrease with increase of NMHC concentrations. DA - 2006/// PY - 2006/// DO - 10.1504/ijgenvi.2006.010147 VL - 6 IS - 2-3 SP - 149-172 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33746185438&partnerID=MN8TOARS ER - TY - JOUR TI - Modelling and analysis of the atmospheric nitrogen deposition in North Carolina AU - Phillips, S.B. AU - Aneja, V.P. AU - Kang, D. AU - Arya, S.P. T2 - International Journal of Global Environmental Issues AB - The availability of detailed environmental data, together with inexpensive and powerful computers, has fueled a rapid increase in predictive modeling of species environmental requirements and geographic distributions. For some species, detailed presence/absence occurrence data are available, allowing the use of a variety of standard statistical techniques. However, absence data are not available for most species. In this paper, we introduce the use of the maximum entropy method (Maxent) for modeling species geographic distributions with presence-only data. Maxent is a general-purpose machine learning method with a simple and precise mathematical formulation, and it has a number of aspects that make it well-suited for species distribution modeling. In order to investigate the efficacy of the method, here we perform a continental-scale case study using two Neotropical mammals: a lowland species of sloth, Bradypus variegatus, and a small montane murid rodent, Microryzomys minutus. We compared Maxent predictions with those of a commonly used presence-only modeling method, the Genetic Algorithm for Rule-Set Prediction (GARP). We made predictions on 10 random subsets of the occurrence records for both species, and then used the remaining localities for testing. Both algorithms provided reasonable estimates of the species’ range, far superior to the shaded outline maps available in field guides. All models were significantly better than random in both binomial tests of omission and receiver operating characteristic (ROC) analyses. The area under the ROC curve (AUC) was almost always higher for Maxent, indicating better discrimination of suitable versus unsuitable areas for the species. The Maxent modeling approach can be used in its present form for many applications with presence-only datasets, and merits further research and development. DA - 2006/// PY - 2006/// DO - 10.1016/j.ecolmodel.2005.03.026 VL - 6 IS - 2-3 SP - 231-252 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33746218412&partnerID=MN8TOARS KW - maximum entropy KW - distribution KW - modeling KW - niche KW - range ER - TY - CONF TI - Application and evaluation of MM5 for North Carolina with a 4-km horizontal grid spacing AU - Krishnan, S. AU - Wu, S.-Y. AU - Hamilton, D. AU - Zhang, Y. AU - Aneja, V.P. C2 - 2006/// C3 - 86th AMS Annual Meeting DA - 2006/// UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-77949293374&partnerID=MN8TOARS ER - TY - CONF TI - Comparison of North American and Paleartic Unionid Bivalves: A Contrast: The Classifications Of Haas And Starobogatov AU - Bogan, AE AU - Mandryka, O AU - Mock, Ke AU - Hoeh, Wr AU - Raley, Me AU - Levine, Jf T2 - First Baltic Symposium of Malacology: Diversity and Conservation of European Molluscan Fauna C2 - 2006/9// CY - Riga, Latvia DA - 2006/9// PY - 2006/9// ER - TY - CONF TI - Rapid And Specific Real-Time Polymerase Chain Reaction Method For Detection of Viable Salmonella spp. in Poultry Feed and Feedstuffs AU - Li, X. AU - Levine, JF T2 - Poultry Science Association Annual Meeting C2 - 2006/7// CY - Edmonton, CA DA - 2006/7// PY - 2006/7// ER - TY - CONF TI - Detection Of Spring Viremia Of Carp Virus By Loop Mediated Isothermal Amplification (Lamp) AU - Shivappa, R.B. AU - Savan, R. AU - Masahiro, S. AU - Levine, J.F. T2 - International Symposium on Aquatic Animal Health C2 - 2006/11// CY - San Francisco, CA DA - 2006/11// PY - 2006/11// ER - TY - CHAP TI - Protistan community structure T2 - Manual of Environmental Microbiology PY - 2006/1/26/ ER - TY - CHAP TI - Bivalves AU - Levine, Jay F. AU - Law, Mac AU - Corsin, Flavio T2 - Invertebrate Medicine A2 - Lewbart, G.A. AB - This chapter contains section titled: Introduction Basic Anatomy and Physiology Behavior Bivalves as Biological Filters Bivalves as Bioindicators Culture Health Requirements References PY - 2006/3/31/ DO - 10.1002/9780470344606.ch7 SP - 91-113 PB - Wiley SN - 9780813818443 9780470344606 UR - http://dx.doi.org/10.1002/9780470344606.ch7 ER - TY - RPRT TI - Mineralization of 2,4,6-Trinitrotoleune (TNT) in Coastal Waters and Sediments AU - Walker, S. W. AU - Osburn, C. L. AU - Boyd, T. J. AU - Hamdan, L. J. AU - Coffin, R. B. AU - Montgomery, M. T. AU - Smith, J. P. AU - Li, Q. X. AU - Monteil, F. AU - Hawari, J. A3 - Defense Technical Information Center AB - Abstract : Mineralization rates of 14C-TNT, -DNT, and -DAT were measured in surface sediments, with depth in sediment cores, and in the water column during 12 research cruises over the past 4 years in the San Francisco Bay, Chesapeake Bay, and Hawaii. Mineralization rates were also compared to uptake and incorporation rates of TNT, DNT, and DAT into the natural microbial assemblage. In general, the bacterial mineralizations rates were similar, or an order of magnitude faster, than those for organic hydrocarbons measured at the same time. Using seawater sampled from a historical UXO field, we found that while bacterial mineralization was rapid (>1 ug L-1 d-1, unfiltered water in dark), photodegradation was even faster (16 ug L-1 d-1, filtered water in light) and the combination of light and unfiltered water was greater than the sum of the two rates (103 ug L-1 d-1), suggesting either that the presence of active phytoplankton is important or photodegradation enhances bacterial mineralization. C6 - NRL/FR/6114–06-10135 DA - 2006/8/21/ PY - 2006/8/21/ DO - 10.21236/ada456842 M1 - NRL/FR/6114--06-10135 M3 - Naval Research Laboratory Formal Report PB - Defense Technical Information Center SN - NRL/FR/6114--06-10135 UR - http://dx.doi.org/10.21236/ada456842 ER - TY - JOUR TI - Regional climate model downscaling of the U.S. summer climate and future change AU - Liang, Xin-Zhong AU - Pan, Jianping AU - Zhu, Jinhong AU - Kunkel, Kenneth E. AU - Wang, Julian X. L. AU - Dai, Aiguo T2 - Journal of Geophysical Research: Atmospheres AB - A mesoscale model (MM5)–based regional climate model (CMM5) integration driven by the Parallel Climate Model (PCM), a fully coupled atmosphere‐ocean‐land‐ice general circulation model (GCM), for the present (1986–1995) summer season climate is first compared with observations to study the CMM5's downscaling skill and uncertainty over the United States. The results indicate that the CMM5, with its finer resolution (30 km) and more comprehensive physics, simulates the present U.S. climate more accurately than the driving PCM, especially for precipitation, including summer mean patterns, diurnal cycles, and daily frequency distributions. Hence the CMM5 downscaling provides a credible means to improve GCM climate simulations. A parallel CMM5 integration driven by the PCM future (2041–2050) projection is then analyzed to determine the downscaling impact on regional climate changes. It is shown that the CMM5 generates climate change patterns very different from those predicted by the driving PCM. A key difference is a summer “warming hole” over the central United States in the CMM5 relative to the PCM. This study shows that the CMM5 downscaling can significantly reduce GCM biases in simulating the present climate and that this improvement has important consequences for future projections of regional climate changes. For both the present and future climate simulations, the CMM5 results are sensitive to the cumulus parameterization, with strong regional dependence. The deficiency in representing convection is likely the major reason for the PCM's unrealistic simulation of U.S. precipitation patterns and perhaps also for its large warming in the central United States. DA - 2006/5/27/ PY - 2006/5/27/ DO - 10.1029/2005JD006685 VL - 111 IS - D10 SP - n/a-n/a J2 - J. Geophys. Res. LA - en OP - SN - 0148-0227 UR - http://dx.doi.org/10.1029/2005JD006685 DB - Crossref ER - TY - JOUR TI - Chemical aging and the hydrophobic-to-hydrophilic conversion of carbonaceous aerosol AU - Petters, Markus D. AU - Prenni, Anthony J. AU - Kreidenweis, Sonia M. AU - DeMott, Paul J. AU - Matsunaga, Aiko AU - Lim, Yong B. AU - Ziemann, Paul J. T2 - Geophysical Research Letters AB - Laboratory experiments simulating chemical aging of carbonaceous aerosol by atmospheric oxidants demonstrate that oxidative processing increases their ability to activate as cloud droplets. A microphysical model shows, however, that the measured increase in hygroscopicity is insufficient to lead to efficient wet scavenging for sub‐100 nm particles that are typically emitted from combustion sources. The absence of an efficient atmospheric oxidation pathway for hydrophobic‐to‐hydrophilic conversion suggests that the fate of carbonaceous aerosol is instead controlled by its interaction with more hydrophilic species such as sulfates, nitrates, and secondary organic aerosol, leading to longer lifetimes, higher burdens, and greater contributions to climate forcing in the free troposphere than are currently estimated. DA - 2006/12/19/ PY - 2006/12/19/ DO - 10.1029/2006GL027249 VL - 33 IS - 24 J2 - Geophys. Res. Lett. LA - en OP - SN - 0094-8276 UR - http://dx.doi.org/10.1029/2006GL027249 DB - Crossref ER - TY - JOUR TI - Deliquescence-controlled activation of organic aerosols AU - Kreidenweis, Sonia M. AU - Petters, Markus D. AU - DeMott, Paul J. T2 - Geophysical Research Letters AB - We examine the cloud condensation nucleation behavior expected for dry submicron particles composed of organic species having limited solubility in water and thus exhibiting deliquescence only under water‐supersaturated conditions. If saturated solution water activities a w are approximately 0.97 < a w < 1, then deliquescence is likely to control the supersaturation required to activate submicron particles, leading to high sensitivity of critical supersaturation to dry diameter. Similar behavior may occur for species, including polymeric compounds, that exhibit limited miscibility in water until very dilute conditions. Treating the sparingly‐soluble or limited‐miscibility species as insoluble aerosol components in calculations of their hygroscopic growth does not reproduce the predicted strong dependence of critical supersaturation on dry particle size. Lack of information on the solubility characteristics of organic‐species‐dominated atmospheric particulate matter may thus lead to discrepancies between predicted and measured droplet activation, even when particle composition and size are well‐constrained by measurements. DA - 2006/// PY - 2006/// DO - 10.1029/2005GL024863 VL - 33 IS - 6 J2 - Geophys. Res. Lett. LA - en OP - SN - 0094-8276 UR - http://dx.doi.org/10.1029/2005GL024863 DB - Crossref ER - TY - JOUR TI - Accumulation mode aerosol, pockets of open cells, and particle nucleation in the remote subtropical Pacific marine boundary layer AU - Petters, Markus D. AU - Snider, Jefferson R. AU - Stevens, Bjorn AU - Vali, Gabor AU - Faloona, Ian AU - Russell, Lynn M. T2 - Journal of Geophysical Research AB - We analyze a marine boundary layer cloud field encountered during the second research flight of the second Dynamics and Chemistry of Marine Stratocumulus Experiment. The cloud field is distinguished by the presence of pockets of open cells. Differences between the pockets and the surrounding stratocumulus clouds are studied utilizing in situ and satellite data. The pockets are characterized as regions where cloud radar echo tops are unusually variable, accumulation mode aerosol concentrations are low, and Aitken mode particles with a mode diameter at 0.02 μm dominate aerosol number concentration. The Aitken mode particles are thought to be generated by a nucleation event which occurred within the marine boundary layer. The low accumulation mode concentrations associated with the pockets are proposed to be necessary for their maintenance. DA - 2006/// PY - 2006/// DO - 10.1029/2004JD005694 VL - 111 IS - D2 J2 - J. Geophys. Res. LA - en OP - SN - 0148-0227 UR - http://dx.doi.org/10.1029/2004JD005694 DB - Crossref ER - TY - JOUR TI - Flexing is not stretching: An analogue study of flexure-induced fault populations AU - Supak, S AU - Bohnenstiehl, D AU - Buck, W T2 - Earth and Planetary Science Letters AB - Flexure-induced fractures are predicted to form along the axis of maximum tensile stress within a bending brittle plate. The mechanics of this process differ from extensional fault growth in response to lithosphere stretching, where a distributed set of simultaneously growing fractures evolves through elastic interaction. To simulate extensional fault growth during lithospheric flexure, partially solidified plaster layers resting on a foam rubber substrate were depressed by a linear load and fractured in analogue models. The length- and spacing-frequency distributions of the resulting crack populations were analyzed for a series of nine thin (5 mm) and ten thick (15 mm) layer experiments. Previous analogue stretching models predict power-law length-frequency distributions and clustered spacings (Cv > 1) at low strains (< ~ 10%), evolving toward an exponential distribution and more regular spacings (Cv < 1, often termed anticlusted) at larger stains. Crack populations formed at low strains during these bending experiments, however, exhibit length-frequency distributions that are not well described by either a power-law or exponential distribution model, being somewhat better fit by the exponential model in the thin layer experiments and somewhat better fit by the power-law model in the thick layer experiments. One-dimensional spacing-frequency distributions are well described by an exponential distribution model, and crack spacing can be characterized as anticlustered within both the thin and thick layer experiments. Although similar spacing patterns may develop when fracture growth is limited by mechanical layer thickness, the characteristic spacing does not scale with the layer thickness in these flexural experiments. Alternatively, the development of power-law (fractal) populations may be inhibited by the growth history of flexure-induced faults, whereby nucleation is localized spatially due to the distribution of stresses within bending plate. These analogue experiments may be relevant to the outer-rise regions of subduction zones, where the oceanic plate is flexed downward, and the abyssal flanks adjacent to fast-spreading mid-ocean ridge crests, where recent models for axial high development suggest that the plate is unbent as it rafts away from the axis. DA - 2006/6/15/ PY - 2006/6/15/ DO - 10.1016/j.epsl.2006.03.028 VL - 246 IS - 1-2 SP - 125-137 J2 - Earth and Planetary Science Letters LA - en OP - SN - 0012-821X UR - http://dx.doi.org/10.1016/j.epsl.2006.03.028 DB - Crossref KW - extensional faulting KW - mid-ocean ridges KW - subduction KW - analogue models KW - lithosphere flexure KW - outer-rise ER - TY - JOUR TI - Hydroacoustic contributions to understanding the December 26th 2004 great Sumatra–Andaman Earthquake AU - Tolstoy, Maya AU - Bohnenstiehl, DelWayne R. T2 - Surveys in Geophysics DA - 2006/8/1/ PY - 2006/8/1/ DO - 10.1007/s10712-006-9003-6 VL - 27 IS - 6 SP - 633-646 J2 - Surv Geophys LA - en OP - SN - 0169-3298 1573-0956 UR - http://dx.doi.org/10.1007/s10712-006-9003-6 DB - Crossref KW - T-wave KW - hydrophone KW - hydroacoustic KW - Sumatra-Andaman earthquake KW - rupture speed ER - TY - CONF TI - Cape Fear River Estuary Plume Modeling: Model Configuration and Sensitivity Experiments AU - Xia, Meng AU - Xie, Lian AU - Pietrafesa, Leonard J. T2 - Ninth International Conference on Estuarine and Coastal Modeling AB - In this study, Environmental Fluid Dynamic Code (EFDC) is used to simulate the salinity plume distribution in the mouth of the Cape Fear River Estuary (CFRE). Effects of astronomical tide, river discharge and wind on the CFRE salinity plume were investigated. The spatial and temporal characteristics of the model simulated salinity plume are compared with observations measured by the Coastal Ocean Research and Monitoring Program (CORMP). The results indicate that model results and observations show a good agreement in water level and salinity. The simulations also indicate that strong winds tend to reduce the surface CFRE plume size and distorting the bulge region near the estuary mouth due to enhanced wind induced surface mixing. Even moderate wind speeds could fully reverse the buoyancy-driven plume structure in CFRE under normal river discharge conditions. Tide and the river. discharge also important factors .... C2 - 2006/7/14/ C3 - Estuarine and Coastal Modeling (2005) DA - 2006/7/14/ DO - 10.1061/40876(209)6 PB - American Society of Civil Engineers SN - 9780784408766 UR - http://dx.doi.org/10.1061/40876(209)6 DB - Crossref ER - TY - JOUR TI - Emerging national research needs for agricultural air quality AU - Aneja, Viney P. AU - Schlesinger, William H. AU - Nyogi, Dev AU - Jennings, Greg AU - Gilliam, Wendell AU - Knighton, Raymond E. AU - Duke, Clifford S. AU - Blunden, Jessica AU - Krishnan, Srinath T2 - Eos, Transactions American Geophysical Union AB - Over the next 50 years, the Earth's human population is predicted to increase from the current 6.1 billion to more than 9 billion, creating a parallel increase in demand for agricultural commodities. Satisfying the demand for food is already driving changes in crop and livestock production methods that may have profound environmental effects. Increased consumption of animal protein in developed and developing countries, for example, has resulted in concentrated production of poultry and livestock, which has led to concentrated emissions of pollutants from these production facilities and has created regulatory concerns for agriculture. Development of land for nonagricultural uses has placed more pressure on marginal agricultural lands and has caused environmental degradation including the emission of trace gases (e.g., carbon,sulfur, and nitrogen species) into the atmosphere. DA - 2006/// PY - 2006/// DO - 10.1029/2006EO030001 VL - 87 IS - 3 SP - 25 J2 - Eos Trans. AGU LA - en OP - SN - 0096-3941 UR - http://dx.doi.org/10.1029/2006EO030001 DB - Crossref ER - TY - PAT TI - Variable depth automated dynamic water profiler T2 - U.S. Patent and Trade Office C2 - 2006/5/9/ DA - 2006/5/9/ PY - 2006/5/9/ UR - http://www.lib.ncsu.edu/resolver/1840.2/1017 ER - TY - JOUR TI - Compound-Specific Isotope Analysis Coupled with Multivariate Statistics to Source-Apportion Hydrocarbon Mixtures AU - Boyd, Thomas J. AU - Osburn, Christopher L. AU - Johnson, Kevin J. AU - Birgl, Keri B. AU - Coffin, Richard B. T2 - Environ. Sci. Technol. AB - Compound Specific Isotope Analysis (CSIA) has been shown to be a useful tool for assessing biodegradation, volatilization, and hydrocarbon degradation. One major advantage of this technique is that it does not rely on determining absolute or relative abundances of individual components of a hydrocarbon mixture which may change considerably during weathering processes. However, attempts to use isotopic values for linking sources to spilled or otherwise unknown hydrocarbons have been hampered by the lack of a robust and rigorous statistical method for testing the hypothesis that two samples are or are not the same. Univariate tests are prone to Type I and Type II error, and current means of correcting error make hypothesis testing of CSIA source-apportionment data problematic. Multivariate statistical tests are more appropriate for use in CSIA data. However, many multivariate statistical tests require high numbers of replicate measurements. Due to the high precision of IRMS instruments and the high cost of CSIA analysis, it is impractical, and often unnecessary, to perform many replicate analyses. In this paper, a method is presented whereby triplicate CSIA information can be projected in a simplified data-space, enabling multivariate analysis of variance (MANOVA) and highly precise testing of hypotheses between unknowns and putative sources. The method relies on performing pairwise principal components analysis (PCA),then performing a MANOVA upon the principal component variables (for instance, three, using triplicate analyses) which capture most of the variability in the original data set. A probability value is obtained allowing the investigator to state whether there is a statistical difference between two individual samples. A protocol is also presented whereby results of the coupled pairwise PCA-MANOVA analysis are used to down-select putative sources for other analysis of variance methods (i.e., PCA on a subset of the original data) and hierarchical clustering to look for relationships among samples which are not significantly different. A Monte Carlo simulation of a 10 variable data set; tanks used to store, distribute, and offload fuels from Navy vessels; and a series of spilled oil samples and local tug boats from Norfolk, VA (U.S.A.) were subjected to CSIA and the statistical analyses described in this manuscript, and the results are presented. The analysis techniques described herein combined with traditional forensic analyses provide a collection of tools suitable for source-apportionment of hydrocarbons and any organic compound amenable to GC-combustion-IRMS. DA - 2006/3// PY - 2006/3// DO - 10.1021/es050975p VL - 40 IS - 6 SP - 1916-1924 ER - TY - CONF TI - Characterization of jetting-induced disturbance zones AU - Gabr, M. A. AU - Borden, R. H. AU - Smith, A. W. AU - Denton, R. L. AU - Eggleston, D. B. AU - Broome, S. W. C2 - 2006/// C3 - 3rd Annual GEO3 T2 conference & expo 2006, Charlotte, April, 2006 DA - 2006/// PB - Raleigh, NC: NC Department of Transportation ER - TY - RPRT TI - Digital landslide inventory for the Cowlitz County Urban Corridor, Washington AU - Wegmann, K. W. A3 - Washington Division of Geology and Earth Resources DA - 2006/// PY - 2006/// PB - Washington Division of Geology and Earth Resources ER - TY - JOUR TI - Using conceptests to assess and improve student conceptual understanding in introductory geoscience courses AU - McConnell, D. A. AU - Steer, D. N. AU - Owens, K. AU - Borowski, W. AU - Dick, J. AU - Foos, A. AU - Knott, J. R. AU - Malone, M. AU - McGrew, H. AU - Van Horn, S. AU - Greer, L. AU - Heaney, P. J. T2 - Journal of Geoscience Education AB - Conceptests are higher-order multiple-choice questions that focus on one key concept of an instructor's major learning goals for a lesson. When coupled with student interaction through peer instruction, conceptests represent a rapid method of formative assessment of student understanding, require minimal changes to the instructional environment and introduce many of the recognized principles of effective teaching that enhance student learning. In this study, instructors from several different institutions developed over 300 conceptests for the geosciences. These instructors then used this suite of concept questions in a wide range of classroom settings, including large introductory general education Earth Science courses for non-majors at open enrollment institutions, smaller physical geology classes suitable for majors at private colleges, and in introductory geology laboratory settings. Results of pre- and post-class Geoscience Concept Inventory (GCI) testing and qualitative feedback from students and instructors showed that conceptests increased attendance, improved student satisfaction, and enhanced student achievement. Participating instructors found implementation of conceptests into their classes straightforward and required less than 30 minutes of preparation per class. The conceptest question database is available on-line for geoscience instructors. DA - 2006/// PY - 2006/// DO - 10.5408/1089-9995-54.1.61 VL - 54 IS - 1 SP - 61-68 ER - TY - JOUR TI - Researcher, Teacher, Education Researcher: The Evolution of a University Geoscience Instructor AU - Owens, Katharine D. AU - Steer, David AU - McConnell, David T2 - SCHOOL SCIENCE AND MATHEMATICS AB - This case study describes a professor's evolution from geoscience researcher to effective teacher to education researcher. The article details his initial beliefs about teaching, looks at the factors that prompted him to seek a different teaching approach, and enumerates the supports and challenges that he had on his journey. Factors essential to this evolution are early career success in discipline research, an institutional climate to reward teaching, mentoring support by colleagues, access to professional development opportunities, and involvement in action research activities. The case study is linked to education literature about teaching and education research and makes recommendations based on the findings of the study. DA - 2006/1// PY - 2006/1// DO - 10.1111/j.1949-8594.2006.tb18068.x VL - 106 IS - 1 SP - 27-35 SN - 1949-8594 ER - TY - JOUR TI - Impact of large poultry operations on groundwater: Stable 15N isotopes of nitrate assessment AU - Showers, W. J. AU - Williams, C. M. AU - Jennings, G. D. T2 - International Journal of Poultry Science DA - 2006/// PY - 2006/// DO - 10.3923/ijps.2006.318.329 VL - 5 IS - 4 SP - 318 ER - TY - JOUR TI - Dynamic atmospheric chamber systems: Applications to trace gas emissions from soil and plant uptake AU - Aneja, Viney AU - Blunden, J. AU - Claiborn, C.S. AU - Rogers, H.H. T2 - International Journal of Global Environmental Issues AB - Atmospheric emissions, transport, transformation and deposition of trace gases may be simulated through chambers. The dynamic flow-through chamber system has been developed in response to a need to measure emissions of nitrogen, sulphur and carbon compounds for a variety of field applications. Oxides of nitrogen (NO, NO2, NOY) emissions have been measured from agricultural fertilised/unfertilised soils. Ammonia-nitrogen (NH3–N) and reduced organic sulphur compound emissions have been measured using this same technique across a gas-liquid and soil-atmosphere interface at swine waste treatment anaerobic storage lagoons and in agricultural fields. Similar chamber systems have also been deployed to measure the uptake of nitrogen, sulphur, ozone and hydrogen peroxide gases by crops and vegetation to examine atmospheric-biospheric interactions. Emission measurements compare well with a coupled gas-liquid transfer with chemical reaction model as well as a US Environmental Protection Agency (EPA) WATER9 model. DA - 2006/// PY - 2006/// DO - 10.1504/ijgenvi.2006.010157 VL - 6 IS - 2-3 SP - 253-269 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33746358849&partnerID=MN8TOARS ER - TY - JOUR TI - An integrated perspective on assessing agricultural air quality AU - Aneja, Viney AU - Niyogi, D. AU - Roelle, P.A. T2 - International Journal of Global Environmental Issues AB - The biogeochemical cycling of trace gases (e.g. nitrogen, sulphur, etc.), and contaminants on local, regional, and global scales is a complex system of emissions, transformations, transport, and deposition. To date, limited, if any, attempt has been made on quantifying and identifying direct emissions of gaseous sulphur compounds from agricultural operations. This represents a major regulatory need for sound and prudent environmental practice. In this paper, we summarise an integrated assessment framework for studying the agricultural air quality issues by discussing the various components of the research, education and outreach involved. DA - 2006/// PY - 2006/// DO - 10.1504/ijgenvi.2006.010146 VL - 6 IS - 2-3 SP - 137-148 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33746227332&partnerID=MN8TOARS ER - TY - JOUR TI - Development and evaluation of a forecasting system for fungal disease in turfgrass AU - Palmieri, Richard AU - Tredway, Lane AU - Niyogi, Dev AU - Lackmann, Gary M. T2 - METEOROLOGICAL APPLICATIONS AB - Abstract A forecasting system for fungal infection of turfgrass using weather‐based empirical indices (the ‘Fidanza’ and ‘Schumann’ models) was developed and evaluated for its ability to predict the occurrence of brown patch (Rhizoctonia blight) infection episodes at an experimental site in southeastern USA. Disease observations took place at the Turfgrass Field Laboratory in Raleigh, North Carolina between 8 June and 17 August 2003. Three meteorological data sources were used to generate disease risk indices using the empirical models: an on‐site observing station, an observing station at a nearby airport, and the US National Weather Service's operational Eta weather forecast model. Visual observations of brown patch activity were conducted in the field and used to evaluate the accuracy of the disease prediction models. Results indicate that the Fidanza and Schumann models correctly predicted brown patch activity on 48% and 30% of the days on which disease occurred, respectively. A diagnosis of the model performance of these disease indices was undertaken. Results are dependent on occurrence of high temperatures and rainfall and independent of the source of the meteorological information (on‐site, airport and the Eta model); therefore, regional meteorological information can be effectively applied to develop turfgrass disease forecasting systems. Ongoing efforts are directed towards developing new disease indices and modifying existing indices before an operational disease forecasting system can be implemented. Copyright © 2006 John Wiley & Sons, Ltd. DA - 2006/12// PY - 2006/12// DO - 10.1017/S1350482706002428 VL - 13 IS - 4 SP - 405-416 SN - 1469-8080 KW - turf disease forecast system KW - plant pathology KW - agriculture meteorology KW - plant disease KW - Eta model ER - TY - JOUR TI - Nitrate uptake by Karenia brevis. II. Behavior and uptake physiology in a nitrate-depleted mesocosm with a bottom nutrient source AU - Sinclair, Geoffrey A. AU - Kamykowski, Daniel AU - Milligan, Edward AU - Schaeffer, Blake 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 328:125-131 (2006) - doi:10.3354/meps328125 Nitrate uptake by Karenia brevis. II. Behavior and uptake physiology in a nitrate-depleted mesocosm with a bottom nutrient source Geoffrey A. Sinclair*, Daniel Kamykowski, Edward Milligan, Blake Schaeffer Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Campus Box 8208, Raleigh, North Carolina 27695-8208, USA *Email: gasincla@ncsu.edu ABSTRACT: Karenia brevis may optimize growth by alternately maximizing exposure to light, migrating up into an oligotrophic water column during the day, and to nutrients (nitrate), by migrating down to the sediment-water interface at night. Understanding how cell behavior contributes to the acquisition of light and nutrients that are separated in space is critical to understanding how K. brevis populations persist in oligotrophic environments. In response to previous modeling efforts that parameterized cell physiology and behavior in nitrate-replete conditions, we examined similar cellular characteristics in a stratified 1.5 m deep mesocosm. The upper 2/3 of the mesocosm, encompassing the surface and middle samples, was nitrate depleted (<0.5 µM NO3–) and simulated an oligotrophic water column. The lower 1/3 of the mesocosm contained 10 µM NO3– corresponding to elevated nutrient levels near the sediment–water interface. We sampled uptake rates at 3 depths during the day at light levels of 350, 125 and 60 µmol quanta m–2 s–1 and again at night in the dark. Nocturnal uptake of nitrate in the mesocosm was significantly less than diurnal uptake. Nocturnal uptake rates in the mesocom were intermediate between cells exposed to prolonged nitrate-depleted and nitrate-replete conditions. Both migration, as indicated by diel aggregation patterns, and cell physiology indicate that descent to regions of higher nutrient concentrations were sufficient to maintain average growth rates of 0.3 div d–1. Thus, both the physiology and behavior of K. brevis may support populations near the sediment–water interface, where they may grow undetected in offshore oligotrophic water columns. KEY WORDS: Karenia brevis · Dinoflagellate · Physiology · Nocturnal uptake · Vertical migration · Sediment Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 328. Online publication date: December 20, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research. DA - 2006/// PY - 2006/// DO - 10.3354/meps328125 VL - 328 SP - 125-131 SN - 1616-1599 KW - Karenia brevis KW - dinoflagellate KW - physiology KW - nocturnal uptake KW - vertical migration KW - sediment ER - TY - JOUR TI - Nitrate uptake by Karenia brevis. I. Influences of prior environmental exposure and biochemical state on diel uptake of nitrate AU - Sinclair, Geoffrey A. AU - Kamykowski, Daniel AU - Milligan, Edward AU - Schaeffer, Blake 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 328:117-124 (2006) - doi:10.3354/meps328117 Nitrate uptake by Karenia brevis. I. Influences of prior environmental exposure and biochemical state on diel uptake of nitrate Geoffrey A. Sinclair*, Daniel Kamykowski, Edward Milligan, Blake Schaeffer Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Campus Box 8208, Raleigh, North Carolina 27695-8208, USA *Email: gasincla@ncsu.edu ABSTRACT: The ability of a Karenia brevis population to persist in an oligotrophic water column depends on how cell physiology and cell behavior contribute to the acquisition of light and nutrients that often are separated in space. We hypothesized that an aggregation of K. brevis, observed undergoing a diel vertical migration (DVM) in the bottom half of a 22 m water column on the West Florida Shelf, used the sediments as a nutrient source. We tested how the physiology of K. brevis contributed to the acquisition of nitrate by evaluating how nitrate uptake changed with prior environmental exposure. The experimental conditions simulated the extremes that cells might endure during DVM when migrating up into an oligotrophic water column versus cells that remained near the sediment-water interface. The first culture, representing cells that attained the maximum apex of their migration away from the sediments, was grown under relatively high light (350 µmol quanta m–2 s–1) and reached nitrate-depleted conditions (<0.5 µM NO3–) prior to the experiment. The second culture, representing cells that remained near the sediment-water interface, was grown under relatively low light (60 µmol quanta m–2 s–1) and nitrate-replete conditions (~20 µM NO3–) prior to the experiment. Cells exposed to nitrate-depleted environments for 12 h prior to the experiment enhanced nocturnal uptake compared to cells continuously exposed to nitrate-replete conditions. Changes in cell physiology may contribute to nitrate acquisition after descent from oligotrophic environments to areas with elevated nitrate concentrations. KEY WORDS: Karenia brevis · Dinoflagellate · Physiology · Nocturnal uptake · Vertical migration Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 328. Online publication date: December 20, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research. DA - 2006/// PY - 2006/// DO - 10.3354/meps328117 VL - 328 SP - 117-124 SN - 1616-1599 KW - Karenia brevis KW - dinoflagellate KW - physiology KW - nocturnal uptake KW - vertical migration ER - TY - JOUR TI - Formation and maintenance mechanisms of the stable layer over the Po valley during MAP IOP-8 AU - Hoggarth, Allison M. AU - Reeves, Heather Dawn AU - Lin, Yuh-Lang T2 - MONTHLY WEATHER REVIEW AB - Abstract During intensive observation period 8 (IOP-8) of the Mesoscale Alpine Program, a strong stable layer formed over Italy’s Po Valley and the northern Ligurian Sea. This stable layer has been shown in previous research to be important for the formation of convection over the Ligurian Sea and the lack thereof over the Po Valley and southern slopes of the Alps. The purpose of this study is to investigate the mechanisms that acted to form and maintain the stable layer during IOP-8. This aim is accomplished through inspection of observed data as well as numerical simulations and sensitivity experiments. Observations and reanalysis data show that starting on 17 October 1999, a relatively cool, stable air mass was advected around the eastern side of the Alps into the lower atmosphere of the Po Valley. Both observational data and model output show this air mass as being blocked as it encountered the western Alps, thus resulting in an accumulation of cool, stable air at low levels in the Po Valley during the ensuing 60 h. When southerly flow approached northern Italy beginning on 20 October 1999, both the western Alps and the northern Alps appeared to help retain the low-level, cool, stable air over the Po Valley. A trajectory and sounding analysis shows that warmer, less stable air originating from over the southern Mediterranean Sea was advected atop the low-lying stable layer within the Po Valley. It is hypothesized that this differential advection, as well as blocking by the western and northern flanks of the Alps, were responsible for the longevity of the stable layer. A series of numerical simulations and sensitivity experiments were performed to test the above hypotheses. These tests support the hypotheses. Other mechanisms were also considered, including blocking of solar radiation by clouds, friction, and evaporative cooling. These simulations revealed that all three processes were critical for the longevity of the stable layer and point to the importance of accurate model representation of subgrid-scale processes. DA - 2006/11// PY - 2006/11// DO - 10.1175/MWR3251.1 VL - 134 IS - 11 SP - 3336-3354 SN - 0027-0644 ER - TY - JOUR TI - Recommendations for assessing the effectiveness of surrogate species approaches AU - Favreau, Jorie M. AU - Drew, C. Ashton AU - Hess, George R. AU - Rubino, Matthew J. AU - Koch, Frank H. AU - Eschelbach, Katherine A. T2 - BIODIVERSITY AND CONSERVATION DA - 2006/11// PY - 2006/11// DO - 10.1007/s10531-005-2631-1 VL - 15 IS - 12 SP - 3949-3969 SN - 1572-9710 KW - effectiveness KW - flagship species KW - focal species KW - indicator species KW - keystone species KW - surrogate species KW - umbrella species ER - TY - JOUR TI - Co-occurrence of white shrimp, Litopenaeus vannamei, mortalities and microcystin toxin in a southeastern USA shrimp facility AU - Zimba, Paul V. AU - Camus, Al AU - Allen, Elle H. AU - Burkholder, JoAnn M. T2 - AQUACULTURE AB - Various freshwater and marine algal toxins are known to affect plants, fishes, mammals, and invertebrates. During recent mortality events in Texas white shrimp aquaculture ponds, water and shrimp tissue samples were analyzed for cyanobacterial toxins and found to contain microcystin-LR. Cyanoprokaryota dominated the phytoplankton assemblage in water from the affected pond, particularly Microcystis aeruginosa and Anabaena sp. Water samples from the affected pond also contained high levels of microcystin-LR (45 μg/l), whereas adjacent ponds had a diatom-green algal assemblage and no measurable toxin. Unialgal isolates of M. aeruginosa from the affected pond produced microcystin-LR. Free microcystin-LR concentrations in dead shrimp hepatopancreas determined by HPLC were 55 μg/g total shrimp weight, whereas shrimp hepatopancreas from the adjacent pond without shrimp mortalities had no measurable toxin. Muscle toxin concentration was below 0.1 μg/g. DA - 2006/12/1/ PY - 2006/12/1/ DO - 10.1016/j.aquaculture.2006.08.037 VL - 261 IS - 3 SP - 1048-1055 SN - 1873-5622 KW - cyanobacteria KW - cyanoprokaryota KW - Microcystis KW - microcystin KW - shrimp KW - toxic algae KW - toxin ER - TY - JOUR TI - Abundance, biomass and species composition of nearshore fish assemblages in Ghana, West Africa AU - Nunoo, F. K. E. AU - Eggleston, D. B. AU - Vanderpuye, C. J. T2 - AFRICAN JOURNAL OF MARINE SCIENCE AB - Abstract Many of the world's fish populations are overexploited, including Ghana's fish resources. This study examines spatio-temporal trends in fish species composition in relation to biotic, abiotic and anthropogenic factors, towards achieving better-informed management of the beach-seine fisheries. Fishery-dependent data were collected between November 1999 and October 2001 from 94 beach-seine hauls fished at two stations along the Ghanaian coast. The catch consisted of fish, crustaceans, other invertebrates, and macroalgae. Generally, juveniles of species that are exploited by offshore fisheries were found in the catches. Species abundance and their occurrence generally peaked between November and January. Duration of solar radiation and tide level appeared to be important predictors of fish biomass. It is important to exploit the nearshore fish assemblage sustainably because of its nursery role. A co-managed (fishers and government) three-month ban on beach-seining (between May and July) is recommended as the most appropriate control measure towards the sustainability of Ghanaian fish stocks. Keywords: ARTISANALBEACH-SEINEFISHERIESGHANANEARSHORESURF ZONEWEST AFRICA DA - 2006/11// PY - 2006/11// DO - 10.2989/18142320609504217 VL - 28 IS - 3-4 SP - 689-696 SN - 1814-232X KW - artisanal KW - beach-seine KW - fisheries KW - Ghana KW - nearshore KW - surf zone KW - West Africa ER - TY - JOUR TI - A comment on "Bathymetry gradients of lineated abyssal hills: Inferring seafloor spreading vectors and a new model for hills formed at ultra-fast spreading rates" by K.A. Kriner et al. [Earth Planet. Sci. Lett. 242 (2006) 98-110] AU - Bohnenstiehl, DelWayne R. T2 - EARTH AND PLANETARY SCIENCE LETTERS DA - 2006/12/15/ PY - 2006/12/15/ DO - 10.1016/j.epsl.2006.10.012 VL - 252 IS - 3-4 SP - 490-494 SN - 1385-013X ER - TY - JOUR TI - Simulated physical mechanisms associated with climate variability over Lake Victoria basin in East Africa AU - Anyah, Richard O. AU - Semazzi, Fredrick H. M. AU - Xie, Lian T2 - MONTHLY WEATHER REVIEW AB - Abstract A fully coupled regional climate, 3D lake modeling system is used to investigate the physical mechanisms associated with the multiscale variability of the Lake Victoria basin climate. To examine the relative influence of different processes on the lake basin climate, a suite of model experiments were performed by smoothing topography around the lake basin, altering lake surface characteristics, and reducing or increasing the amount of large-scale moisture advected into the lake region through the four lateral boundaries of the model domain. Simulated monthly mean rainfall over the basin is comparable to the satellite (Tropical Rainfall Measuring Mission) estimates. Peaks between midnight and early morning hours characterize the simulated diurnal variability of rainfall over the four quadrants of the lake, consistent with satellite estimates, although the simulated peaks occur a little earlier. It is evident in the simulations with smoothed topography that the upslope/downslope flow generated by the mountains east of the lake and the land–lake breeze circulations play important roles in influencing the intensity, the location of lake/land breeze fronts, and the horizontal extent of the land–lake breeze circulation, as well as lake basin precipitation. When the lake surface is replaced with marsh (water hyacinth), the late night and early morning rainfall maximum located over the western sector of the lake is dramatically reduced. Our simulations also indicate that large-scale moisture transported via the prevailing easterly trades enhances lake basin precipitation significantly. This is in contrast to the notion advanced in some of the previous studies that Lake Victoria generates its own climate (rainfall) through precipitation–evaporation–reprecipitation recycling only. DA - 2006/12// PY - 2006/12// DO - 10.1175/MWR3266.1 VL - 134 IS - 12 SP - 3588-3609 SN - 1520-0493 ER - TY - JOUR TI - Sedimentary features of the Yangtze River-derived along-shelf clinoform deposit in the East China Sea AU - Liu, J.P. AU - Li, A.C. AU - Xu, K.H. AU - Velozzi, D.M. AU - Yang, Z.S. AU - Milliman, J.D. AU - DeMaster, D.J. T2 - Continental Shelf Research AB - A predominant sigmoidal clinoform deposit extends from the Yangtze River mouth southwards 800 km along the Chinese coast. This clinoform is thickest (∼40 m) between the 20 and 30 m isobaths and progressively thins offshore, reaching water depths of 60 and 90 m and distances up to 100 km offshore. Clay mineral, heavy metal, geochemical and grain-size analyses indicate that the Yangtze River is the primary source for this longshore-transported clinoform deposit. 210Pb chronologies show the highest accumulation rates (>3 cm/yr) occur immediately adjacent to the Yangtze subaqueous delta (north of 30 °N), decreasing southward alongshore and eastward offshore. The interaction of strong tides, waves, the China Coastal Current, winter storms, and offshore upwelling appear to have played important roles in trapping most Yangtze-derived sediment on the inner shelf and transporting it to the south. DA - 2006/11// PY - 2006/11// DO - 10.1016/j.csr.2006.07.013 VL - 26 IS - 17-18 SP - 2141-2156 J2 - Continental Shelf Research LA - en OP - SN - 0278-4343 UR - http://dx.doi.org/10.1016/j.csr.2006.07.013 DB - Crossref KW - East China Sea KW - Yangtze river KW - deltaic sedimentation KW - clinoform KW - along-shelf ER - TY - JOUR TI - Potential individual versus simultaneous climate change effects on soybean (C-3) and maize (C-4) crops: An agrotechnology model based study AU - Mera, Roberto J. AU - Niyogi, Dev AU - Buol, Gregory S. AU - Wilkerson, Gail G. AU - Semazzi, Fredrick H. M. T2 - GLOBAL AND PLANETARY CHANGE AB - Landuse/landcover change induced effects on regional weather and climate patterns and the associated plant response or agricultural productivity are coupled processes. Some of the basic responses to climate change can be detected via changes in radiation (R), precipitation (P), and temperature (T). Past studies indicate that each of these three variables can affect LCLUC response and the agricultural productivity. This study seeks to address the following question: What is the effect of individual versus simultaneous changes in R, P, and T on plant response such as crop yields in a C3 and a C4 plant? This question is addressed by conducting model experiments for soybean (C3) and maize (C4) crops using the DSSAT: Decision Support System for Agrotechnology Transfer, CROPGRO (soybean), and CERES-Maize (maize) models. These models were configured over an agricultural experiment station in Clayton, NC [35.65°N, 78.5°W]. Observed weather and field conditions corresponding to 1998 were used as the control. In the first set of experiments, the CROPGRO (soybean) and CERES-Maize (maize) responses to individual changes in R and P (25%, 50%, 75%, 150%) and T (± 1, ± 2 °C) with respect to control were studied. In the second set, R, P, and T were simultaneously changed by 50%, 150%, and ± 2 °C, and the interactions and direct effects of individual versus simultaneous variable changes were analyzed. For the model setting and the prescribed environmental changes, results from the first set of experiments indicate: (i) precipitation changes were most sensitive and directly affected yield and water loss due to evapotranspiration; (ii) radiation changes had a non-linear effect and were not as prominent as precipitation changes; (iii) temperature had a limited impact and the response was non-linear; (iv) soybeans and maize responded differently for R, P, and T, with maize being more sensitive. The results from the second set of experiments indicate that simultaneous change analyses do not necessarily agree with those from individual changes, particularly for temperature changes. Our analysis indicates that for the changing climate, precipitation (hydrological), temperature, and radiative feedbacks show a non-linear effect on yield. Study results also indicate that for studying the feedback between the land surface and the atmospheric changes, (i) there is a need for performing simultaneous parameter changes in the response assessment of cropping patterns and crop yield based on ensembles of projected climate change, and (ii) C3 crops are generally considered more sensitive than C4; however, the temperature–radiation related changes shown in this study also effected significant changes in C4 crops. Future studies assessing LCLUC impacts, including those from agricultural cropping patterns and other LCULC–climate couplings, should advance beyond the sensitivity mode and consider multivariable, ensemble approaches to identify the vulnerability and feedbacks in estimating climate-related impacts. DA - 2006/11// PY - 2006/11// DO - 10.1016/j.gloplacha.2005.11.003 VL - 54 IS - 1-2 SP - 163-182 SN - 1872-6364 KW - land surface response KW - climate change impacts KW - crop yield KW - soybeans KW - maize KW - crop models KW - evapotranspiration ER - TY - JOUR TI - Evidence for carbon dioxide and moisture interactions from the leaf cell up to global scales: Perspective on human-caused climate change AU - Alpert, P. AU - Niyogi, D. AU - Pielke, R. A., Sr. AU - Eastman, J. L. AU - Xue, Y. K. AU - Raman, S. T2 - GLOBAL AND PLANETARY CHANGE AB - It is of utmost interest to further understand the mechanisms behind the potential interactions or synergies between the greenhouse gases (GHG) forcing(s), particularly as represented by CO2, and water processes and through different climatic scales down to the leaf scale. Toward this goal, the factor separation methodology introduced by Stein and Alpert [Stein U. and Alpert, P. 1993. Factor separation in numerical simulations, J. Atmos. Sci., 50, 2107–2115.] that allows an explicit separation of atmospheric synergies among different factors, is employed. Three independent experiments carried out recently by the present authors, are reported here, all strongly suggest the existence of a significant CO2–water synergy in all the involved scales. The experiments employed a very wide range of up-to-date atmospheric models that complement the physics currently introduced in most Global Circulation Models (GCMs) for global climate change prediction. Threemodelingexperimentsthatgofromthesmall/microscale(leafscaleandsoilmoisture) tomesoscale(land-usechangeandCO2 effects ) andtoglobalscale (greenhousegasesand cloudiness)all showthatsynergies between water and CO2are essential inpredicting carbonassimilation,minimumdailytemperatureandtheglobalEarthtemperature,respectively.Thestudyalsohighlightstheimportance of including the physics associated with carbon–water synergy which is mostly unresolved in global climate models suggesting that significantcarbon–waterinteractionsarenotincorporatedoratleastwellparameterizedincurrentclimatemodels.Hence,thereisaneed for integrative climate models. As shown in earlier studies, the climate involves physical, chemical and biological processes. To only include a subset of these processes limits the skill of local, regional and global models to simulate the real climate system. In addition, our results provide explicit determination of the direct and the interactive effect of the CO2 response on the terrestrial biosphere response. There is also an implicit scale interactive effect that can be deduced from the multiscale effects discussed in the three examples.Processesateachscale-leaf,regionalandglobalwillallsynergisticallycontributetoincreasethefeedbacks —whichcandecrease or increase the overall system's uncertainty depending on specific case/setup and needs to beexamined in futurecoupled, multiscalestudies. DA - 2006/11// PY - 2006/11// DO - 10.1016/j.gloplacha.2006.03.015 VL - 54 IS - 1-2 SP - 202-208 SN - 1872-6364 KW - factor separation KW - biosphere atmospheric interactions KW - scale interactions KW - carbon-dioxide assimilation KW - land-use changes KW - coupled carbon-water processes KW - elevated CO2 ER - TY - JOUR TI - Dynamics of track deflection associated with the passage of tropical cyclones over a mesoscale mountain AU - Lin, Yuh-Lang AU - Witcraft, Nicholas C. AU - Kuo, Ying-Hwa T2 - MONTHLY WEATHER REVIEW AB - Abstract In this study, the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) was used to simulate Supertyphoon Bilis (in 2000) and Typhoon Toraji (in 2001) in order to investigate the dynamics of track deflection caused by the Central Mountain Range (CMR) of Taiwan. The MM5 predicted the track of each storm reasonably well. Bilis was stronger and had a relatively faster forward motion, which helped make the track continuous as it crossed the CMR. The use of a “bogus” vortex in the initialization process helped produce a storm closer to the observed strength. Bilis is a classic example of a typhoon crossing Taiwan with a continuous track. For comparison, Typhoon Toraji, a typical typhoon having a discontinuous track, was also studied. Toraji was weaker and had a relatively slower forward speed, which prevented the original low center from crossing over the CMR and forced more air parcels to go around the northern tip of the CMR. As a result, it produced a vortex and a secondary low center on the lee. Potential vorticity banners on the north side of the CMR acted to organize the secondary low and the lee vortex. With time, the low-level circulation extended into the upper levels, completing the formation of the secondary center. Remnants of the initial center crossed over the CMR and were entrained into the secondary center. Nondimensional control parameters for track continuity and deflection from idealized studies are calculated for Bilis and Toraji. The results are consistent with the theory proposed in Lin et al. For tropical cyclones (TCs) approaching Taiwan from the southeast, the conceptual model proposed by Lin et al. for continuous and discontinuous tracks was applied. For continuous tracks over the CMR, the blocking effect on the outer circulation of the vortex is weak and the vorticity advection around the northern tip is strong due to an intense TC. Weak TCs tend to be totally blocked by the CMR. DA - 2006/12// PY - 2006/12// DO - 10.1175/MWR3263.1 VL - 134 IS - 12 SP - 3509-3538 SN - 0027-0644 ER - TY - JOUR TI - Comparison of swimming speed and photophysiological responses to different external conditions among three Karenia brevis strains AU - McKay, Laurie AU - Kamykowski, Daniel AU - Milligan, Ed AU - Schaeffer, Blake AU - Sinclair, Geoff T2 - HARMFUL ALGAE AB - Behavior, growth, and production are integral in the life history of Karenia brevis, an autotrophic, dinoflagellate HAB species, and are important variables in modeling blooms in the Gulf of Mexico. This study compares swimming speeds, growth rates, and photosynthetic responses of recent isolates of K. brevis (specifically the Apalachicola – APA, Manasota – MAN, and Jacksonville – JAX strains) over a range of light intensities and temperatures. Strain swimming speeds were similar and remained fairly constant from 17 to 30 °C, but decreased markedly at 13 °C. Photosynthetic responses of the strains to different acclimated temperatures had opposite trends with APA exhibiting higher electron transport rates (ETR) at higher temperatures and MAN exhibiting higher ETR at lower temperatures. In the light experiments, the cells’ internal physiological state (represented by photosynthetic yield, ETR, and neutral lipid reserves) and swimming capabilities were examined in the dark after 6 h incubations in the radial photosynthetron. For all strains, at initial incubation light intensities swimming speed decreased and ETR increased. As incubation light intensities increased, ETR decreased and swimming speed increased. At the highest incubation light intensities, ETR and swimming speed decreased. Neutral lipids followed a pattern similar to ETR, only lipids peaked after ETR at a light intensity that corresponded to the increase in swimming speed. The results suggest that cells may partition energy selectively depending on the needs of the cell. Information was combined to characterize a generalized species response to light and temperature ranges. DA - 2006/12// PY - 2006/12// DO - 10.1016/j.hal.2005.12.001 VL - 5 IS - 6 SP - 623-636 SN - 1878-1470 KW - behavior KW - dinoflagellate KW - intraspecies comparison KW - Karenia brevis ER - TY - JOUR TI - Carbon remineralization in the Amazon-Guianas tropical mobile mudbelt: A sedimentary incinerator AU - Aller, R. C. AU - Blair, N. E. T2 - Continental Shelf Research AB - The Amazon River spawns a vast mobile mudbelt extending ∼1600 km from the equator to the Orinoco delta. Deposits along the Amazon–Guianas coastline are characterized by some of the highest Corg remineralization rates reported for estuarine, deltaic, or shelf deposits, however, paradoxically, except where stabilized by mangroves or intertidal algal mats, they are usually suboxic and nonsulfidic. A combination of tides, wind-driven waves, and coastal currents forms massive fluid muds and mobile surface sediment layers ∼0.5–2 m thick which are dynamically refluxed and frequently reoxidized. Overall, the seabed functions as a periodically mixed batch reactor, efficiently remineralizing organic matter in a gigantic sedimentary incinerator of global importance. Amazon River material entering the head of this dynamic dispersal system carries an initial terrestrial sedimentary Corg loading of ∼ 0.7 mg C m−2 particle surface area. Total Corg loading is lowered to ∼ 0.2 mg C m−2 in the proximal delta topset, ∼60–70% of which remains of terrestrial origin. Loading decreases further to 0.12–0.14 mg C m−2 (∼60% terrestrial) in mudbanks ∼600 km downdrift along French Guiana, values comparable to those found in the oligotrophic deepsea. DOC/ΣCO2 ratios in pore waters of French Guiana mudbanks indicate that >90% of metabolized organic substrates are completely oxidized. Within the Amazon delta topset at the head of the dispersal system, both terrestrial and marine organic matter contribute substantially to early diagenetic remineralization, although reactive marine substrate dominates (∼60–70%). The conditional rate constant for terrestrial Corg in the delta topset is ∼0.2 a−1. As sedimentary Corg is depleted during transit, marine sources become virtually the exclusive substrate for remineralization except very near the mangrove shoreline. The δ13C and Δ14C values of pore water ΣCO2 in mudbanks demonstrate that the primary source of remineralized organic matter within ∼1 km of shore is a small quantity of bomb signature marine plankton (+80‰). Thus, fresh marine organic material is constantly entrained into mobile deposits and increasingly drives early diagenetic reactions along the transit path. Relatively refractory terrestrial Corg is lost more slowly but steadily during sedimentary refluxing and suboxic diagenesis. Amazon Fan deposits formed during low sea level stand largely bypassed this suboxic sedimentary incinerator and stored material with up to ∼3X the modern high stand inner shelf Corg load (Keil et al., 1997b. Proceedings of the Ocean Drilling Program, Scientific Results. Vol. 155. pp. 531–537). Sedimentary dynamics, including frequency and magnitude of remobilization, and the nature of dispersal systems are clearly key controls on diagenetic processes, biogeochemical cycling, and global C storage along the continental margins. DA - 2006/// PY - 2006/// DO - 10.1016/j.csr.2006.07.016 VL - 26 IS - 17-18 SP - 2241-2259 ER - TY - JOUR TI - A simple model for simulating tornado damage in forests AU - Holland, Andrew P. AU - Riordan, Allen J. AU - Franklin, E. C. T2 - JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY AB - Abstract An analytical model is presented to describe patterns of downed trees produced by tornadic winds. The model uses a combined Rankine vortex of specified tangential and radial components to describe a simple tornado circulation. A total wind field is then computed by adding the forward motion of the vortex. The lateral and vertical forces on modeled tree stands are then computed and are compared with physical characteristics of Scots and loblolly pine. From this model, patterns of windfall are computed and are compared to reveal three basic damage patterns: cross-track symmetric, along-track asymmetric, and crisscross asymmetric. These patterns are shown to depend on forward speed, radial speed, and tree resistance. It is anticipated that this model will prove to be useful in assessing storm characteristics from damage patterns observed in forested areas. DA - 2006/12// PY - 2006/12// DO - 10.1175/JAM2413.1 VL - 45 IS - 12 SP - 1597-1611 SN - 1558-8424 ER - TY - JOUR TI - A new architecture for coastal inundation and flood warning prediction AU - Pietrafesa, L. J. AU - Kelleher, K. AU - Karl, T. AU - Davidson, M. AU - Peng, M. AU - Bao, S. AU - Dickey, D. AU - Xie, L. AU - Liu, H. AU - Xia, M. T2 - MARINE TECHNOLOGY SOCIETY JOURNAL AB - The marine atmosphere, coastal ocean, estuary, harbor and river water systems constitute a physically coupled system. While these systems have always been heavily impacted by coastal storms, increases in population density, infrastructure, and personal and business merchandise have exacerbated the economic and personal impacts of these events over the past half century. As such there has been increased focus on the need for more timely and accurate forecasts of impending events. Traditionally model forecast architectures for coastal storm surge, flooding and inundation of coastal and inland areas have taken the approach of dealing with each system separately: rivers, estuaries, harbors and offshore facing areas. However, given advances in coupled modeling and the availability of real-time data, the ability to accurately predict and project coastal, estuary and inland flooding related to the passage of high energy and wet atmospheric events is rapidly emerging and requires a new paradigm in system architecture. No longer do monthly averaged winds or river discharge or water levels have to be invoked in developing hindcasts for planning purposes or for real-time forecasts. In 1999 a hurricane associated flood on the North Carolina coast took 56 lives and caused more than $6 billion in economic impacts. None of the models existing at that time were able to properly forecast the massive flooding and clearly called for a new model paradigm. Here we propose a model system that couples atmospheric information to fully three dimensional, non-linear time dependent ocean basin, coastal and estuary hydrodynamic models coupled to interactive river models with input of real or modeled winds, observed or modeled precipitation, measured and modeled water levels, and streamflow. The river and estuarine components must both be capable of going into modes of storage or accelerated discharge. Spatial scales must downscale in the horizontal from thousands to tens meters and in the vertical from hundreds to several centimeters. Topography and elevation data should be of the highest resolution available, necessary for highly accurate predictions of the timing and location of the inundation and retreat of flood waters. Precipitation information must be derived from the optimal mix of direct radar, satellite and ground-based observations. Creating the capability described above will advance the modernization of hydrologic services provided by the National Oceanic & Atmospheric Administration and provide more accurate and timely forecasts and climatologies of coastal and estuary flooding. The goal of these climatologies and improved forecasts is to provide better information to local and regional planners, emergency managers, highway patrols and to improve the capacity of coastal communities to mitigate against the impacts of coastal flooding. DA - 2006/// PY - 2006/// DO - 10.4031/002533206787353205 VL - 40 IS - 4 SP - 71-77 SN - 0025-3324 ER - TY - JOUR TI - The spatiotemporal climate variability over Senegal and its relationship to global climate AU - Fall, Souleymane AU - Semazzi, Fredrick H. M. AU - Dutta, Dev AU - Niyogi, S. AU - Anyah, Richard O. AU - Bowden, Jared T2 - INTERNATIONAL JOURNAL OF CLIMATOLOGY AB - Abstract Climate variability over Senegal (West Africa) and its relationship to global climate are examined for the period 1979–1998. Monthly observed rainfall for 20 stations and monthly CPC merged analysis precipitation (CMAP) over Senegal were averaged for the months of June, July, August, and September in order to generate seasonal rainfall totals for the wet season, as well as climate indices averaged over the study period. The spatial distribution patterns are mapped and analyzed using ArcGIS Spatial Analyst. Rainfall distribution over Senegal is dominated by a N–S gradient. To investigate the climate variability over Senegal, an empirical orthogonal function (EOF) analysis is performed for the 1979–1998 period, using rain‐gauge and CMAP rainfall data over Senegal, and CMAP data only for West Africa. The first West African mode agrees strongly with Lamb's rainfall index. One of our major findings is that EOF2 for West Africa is well correlated with EOF1 for rainfall in Senegal. This relationship is supported by the projection of winds on the EOF2 mode by the National Centers for Environmental Prediction (NCEP), as well as the grid‐point correlation between the time series of EOF2 over West Africa and the Atlantic sea‐surface temperature (SST). The typical circulation associated with positive anomalies over Senegal is a moisture convergence, which takes place over the Guinea Gulf, in conjunction with the warm waters in this area. The time series for rainfall over Senegal show positive correlations with the South Atlantic SST. Over the Pacific Ocean, the greatest correlation coefficients (up to −0.72) are observed during the April–July period, which provide a modest possibility of predicting Senegal's rainy season. Given the specificity of coastal West Africa, the traditional indices used by policy makers and end users for the whole Sahel–Sudan region will not work for Senegal. The CMAP data are robust and suitable for analyses over West Africa. On the basis of its reliability, CMAP data has proven to be a good validation for analyses based on rain‐gauge precipitation. Copyright © 2006 Royal Meteorological Society DA - 2006/11/30/ PY - 2006/11/30/ DO - 10.1002/joc.1355 VL - 26 IS - 14 SP - 2057-2076 SN - 1097-0088 UR - http://dx.doi.org/10.1002/joc.1355 KW - Senegal KW - West Africa KW - EOF KW - GIS KW - precipitation KW - temperature ER - TY - JOUR TI - The future of humans in an increasingly automated forecast process AU - Stuart, Neil A. AU - Market, Partick S. AU - Tielfeyan, Bruce AU - Lackmann, Gary M. AU - Carey, Kenneth AU - Brooks, Harold E. AU - Nietfeld, Daniel AU - Motta, Brian C. AU - Reeves, Ken T2 - BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY AB - National Weather Service, Wakefield, VirginiaUniversity of Missouri, Columbia, MissouriAir Force Weather Agency, Offutt AFB, NebraskaNorth Carolina State University, Raleigh, North CarolinaMitretek Systems Inc., Falls Church, VirginiaNational Severe Storms Laboratory, Norman, OklahomaNOAA/National Weather Service, Omaha, NebraskaNational Weather Service, Office of Climate, Water and Weather Services, Boulder, ColoradoAccuWeather, Inc., State College, Pennsylvania* CURRENT AFFILIATION: NOAA/National Weather Service, Albany, New YorkCORRESPONDING AUTHOR: Neil A. Stuart, National Weather Service, 251 Fuller Road, Suite B300, Albany, NY 12203-3640, E-mail: neil.stuart@noaa.gov DA - 2006/11// PY - 2006/11// DO - 10.1175/BAMS-87-11-1497 VL - 87 IS - 11 SP - 1497-1502 SN - 1520-0477 ER - TY - JOUR TI - The effect of changes in surface wettability on two-phase saturated flow in horizontal replicas of single natural fractures AU - Bergslien, Elisa AU - Fountain, John T2 - JOURNAL OF CONTAMINANT HYDROLOGY AB - By using translucent epoxy replicas of natural single fractures, it is possible to optically measure aperture distribution and directly observe NAPL flow. However, detailed characterization of epoxy reveals that it is not a sufficiently good analogue to natural rock for many two-phase flow studies. The surface properties of epoxy, which is hydrophobic, are quite unlike those of natural rock, which is generally assumed to be hydrophilic. Different surface wettabilities result in dramatically different two-phase flow behavior and residual distributions. In hydrophobic replicas, the NAPL flows in well-developed channels, displacing water and filling all of the pore space. In hydrophilic replicas, the invading NAPL is confined to the largest aperture pathways and flow frequently occurs in pulses, with no limited or no stable channel development, resulting in isolated blobs with limited accessible surface area. The pulsing and channel abandonment behaviors described are significantly different from the piston-flow frequently assumed in current modeling practice. In addition, NAPL never achieved total saturation in hydrophilic models, indicating that significantly more than a monolayer of water was bound to the model surface. Despite typically only 60-80% NAPL saturation, there was generally good agreement between theoretically calculated Young-Laplace aperture invasion boundaries and the observed minimum apertures invaded. The key to determining whether surface wettability is negligible, or not, lies in accurate characterization of the contaminant-geologic media system under study. As long as the triple-point contact angle of the system is low (<20 degrees), the assumption of perfect water wettability is not a bad one. DA - 2006/12/15/ PY - 2006/12/15/ DO - 10.1016/j.jconhyd.2006.06.009 VL - 88 IS - 3-4 SP - 153-180 SN - 1873-6009 KW - multiphase flow KW - non-aqueous phase liquids KW - NAPL KW - fracture flow KW - fracture modeling ER - TY - JOUR TI - Status and life-history aspects of Villosa constricta (Conrad 1838) (Notched Rainbow), in the upper Neuse River Basin, North Carolina AU - Eads, Chris B. AU - Bogan, Arthur E. AU - Levine, Jay F. T2 - SOUTHEASTERN NATURALIST AB - We report the findings of stream-survey data, a length-at-age study, and host-fish determination for Villosa constricta (notched rainbow). Visual surveys were done for freshwater mussels at 44 bridge crossings in the upper Neuse River basin in North Carolina. Three surveyors, each searching a 1-m wide lane, covered a 600-m long stream reach at each site. All mussels found were ide.gified to species and measured, and females were checked for gravidity. Of the 24 sites where V. constricta occurred, the median number found was 3.5 (range = 1–54). We cut thin-sections of 71 individual shells collected from middens at 1 survey site and counted growth lines to determine mussel age. Shell ages ranged from 3 to 14 years. Lab trials determined that Etheostoma flabellare (fantail darter) served as a suitable host for this species. DA - 2006/// PY - 2006/// DO - 10.1656/1528-7092(2006)5[649:SALAOV]2.0.CO;2 VL - 5 IS - 4 SP - 649-660 SN - 1938-5412 ER - TY - JOUR TI - A comparison of analysis units for associating Lyme disease with forest-edge habitat AU - Jackson, L. E. AU - Levine, J. F. AU - Hilborn, E. D. T2 - COMMUNITY ECOLOGY DA - 2006/// PY - 2006/// DO - 10.1556/ComEc.7.2006.2.6 VL - 7 IS - 2 SP - 189-197 SN - 1588-2756 KW - fragmentation KW - landscape KW - Maryland KW - modifiable areal unit problem KW - negative binomial model KW - roads KW - scale KW - spatial autocorrelation ER - TY - JOUR TI - Using multispectral satellite imagery to estimate leaf area and response to silvicultural treatments in loblolly pine stands AU - Flores, FJ AU - Allen, HL AU - Cheshire, HM AU - Davis, JM AU - Fuentes, M AU - Kelting, D T2 - CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE AB - The relationship between leaf area index (LAI) of loblolly pine plantations and the broadband simple ratio (SR) vegetation index calculated from Landsat 7 Enhanced Thematic Mapper Plus (ETM+) data was examined. An equation was derived to estimate LAI from readily available Landsat 7 ETM+ data. The equation developed to predict LAI with Landsat 7 ETM+ data was tested with ground LAI measurements taken in 12 plots. The root mean square error of prediction was 0.29, an error of approximately 14% in prediction. The ability of Landsat 7 ETM+ data to consistently estimate SR over time was tested using two scenes acquired on different dates during the winter (December to early March). Comparison between the two images on a pixel-by-pixel basis showed that approximately 96% of the pixels had a difference of <0.5 units of SR (approximately 0.3 units of LAI). When the comparison was made on a stand-by-stand basis (average stand SR), a maximum difference of 0.2 units of SR (approximately 0.12 units of LAI) was found. These results suggest that stand LAI of loblolly pine plantations can be accurately estimated from readily available remote sensing data and provide an opportunity to apply the findings from ecophysiological studies in field plots to forest management decisions at an operational scale. DA - 2006/6// PY - 2006/6// DO - 10.1139/X06-030 VL - 36 IS - 6 SP - 1587-1596 SN - 0045-5067 ER - TY - JOUR TI - Urban and land surface effects on the 30 July 2003 mesoscale convective system event observed in the southern Great Plains AU - Niyogi, D. AU - Holt, T. AU - Zhong, S. AU - Pyle, P. C. AU - Basara, J. T2 - Journal of Geophysical Research. Atmospheres DA - 2006/// PY - 2006/// VL - 111 IS - D19 ER - TY - JOUR TI - The effect of primary productivity and seasonality on the distribution of deep-sea benthic foraminifera in the North Atlantic AU - Sun, XC AU - Corliss, BH AU - Brown, CW AU - Showers, WJ T2 - DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS AB - Deep-sea benthic foraminifera from 43 Holocene core tops in the North Atlantic were studied to evaluate the influence of primary productivity and the seasonality of primary productivity on the distributional patterns of species, faunal assemblages, and microhabitat groups. Two faunal assemblages, Epistominella exigua-Alabaminella weddellensis assemblage and Globocassidulina subglobosa-Epistominella umbonifera assemblage, were found to correlate with seasonality of primary productivity. The E. exigua-A. weddellensis assemblage is found at high latitudes and positively correlates with seasonality, while the G. subglobosa-E. umbonifera assemblage is generally found at low latitudes and has a negative correlation. Correlation analysis indicates that the relative abundance of one species alone (E. exigua or A. weddellensis) is not a strong indicator of either primary productivity or seasonality. No significant relationships are found between benthic foraminiferal species, faunal assemblages, or microhabitat groups and bottom water properties, which suggests that the deep-sea fauna may not be used to reconstruct bottom water properties in this region. Based on microhabitat preferences of individual species, the fauna is categorized into epifaunal, infaunal, and phytodetrital groups and is compared with primary productivity of the overlying surface waters and seasonality. No significant relationship was found between the relative abundance of the infaunal group and primary productivity or its seasonality, and only a weak correlation was found between these variables and the epifaunal group (r2=0.33; 0.46). However, the relative abundances of the phytodetrital group correlate relatively well with seasonal variability (r2=0.63), reflecting the association of these species with phytodetritus in regions marked by high seasonal variation in organic carbon flux. These results indicate that the relative abundance of the phytodetrital group may be used to reconstruct seasonality of productivity in the North Atlantic. DA - 2006/1// PY - 2006/1// DO - 10.1016/j.dsr.2005.07.003 VL - 53 IS - 1 SP - 28-47 SN - 0967-0637 KW - deep-sea benthic foraminifera KW - primary productivity KW - seasonality KW - North Atlantic ER - TY - JOUR TI - Secondary dispersal of early juvenile blue crabs within a wind-driven estuary AU - Reyns, Nathalie B. AU - Eggleston, David B. AU - Luettich, Richard A., Jr. T2 - LIMNOLOGY AND OCEANOGRAPHY AB - We used a coupled biophysical study to examine the processes underlying secondary dispersal of early juvenile blue crabs (Callinectes sapidus) within Pamlico Sound, North Carolina, a predominately wind-driven estuary. We quantified the spatiotemporal distribution of early juvenile blue crabs in the water column with vertically stratified plankton samples (during day-night cruises during two consecutive years) and used a hydrodynamic numerical simulation model to recreate dispersal trajectories and assess potential transport pathways connecting inlet (eastern) and western sound nursery habitats. Early juvenile blue crabs belonging to the first benthic instar stage (J1) were observed within the water column, indicative of secondary dispersal occurring rapidly following postlarval settlement and metamorphosis to the juvenile stage. Moreover, J1 blue crabs were most abundant in near-bottom waters at night. Particle-tracking dispersal simulations revealed that across-sound blue crab secondary dispersal only resulted from the combined use of flood-tides near the inlets and wind-induced bottom currents within the main body of Pamlico Sound. Thus, our results indicate that behavioral responses to multiple hydrodynamic conditions ultimately influence habitat connectivity, particularly in the northwest region of our study area where a distinct transport pathway was evident. As such, generalizations of recruitment dynamics based on systems with strong tidal signals cannot be used to accurately characterize patterns of estuarine recruitment in predominately wind-driven systems. DA - 2006/9// PY - 2006/9// DO - 10.4319/lo.2006.51.5.1982 VL - 51 IS - 5 SP - 1982-1995 SN - 0024-3590 ER - TY - JOUR TI - Perspectives on basaltic magma crystallization and differentiation: Lava-lake blocks erupted at Mauna Loa volcano summit, Hawaii AU - McCarter, Renee' L. AU - Fodor, R. V. AU - Trusdell, Frank T2 - LITHOS AB - Explosive eruptions at Mauna Loa summit ejected coarse-grained blocks (free of lava coatings) from Moku'aweoweo caldera. Most are gabbronorites and gabbros that have 0–26 vol.% olivine and 1–29 vol.% oikocrystic orthopyroxene. Some blocks are ferrogabbros and diorites with micrographic matrices, and diorite veins (≤ 2 cm) cross-cut some gabbronorites and gabbros. One block is an open-textured dunite. The MgO of the gabbronorites and gabbros ranges ∼ 7–21 wt.%. Those with MgO > 10 wt.% have some incompatible-element abundances (Zr, Y, REE; positive Eu anomalies) lower than those in Mauna Loa lavas of comparable MgO; gabbros (MgO < 10 wt.%) generally overlap lava compositions. Olivines range Fo83–58, clinopyroxenes have Mg#s ∼ 83–62, and orthopyroxene Mg#s are 84–63 — all evolved beyond the mineral-Mg#s of Mauna Loa lavas. Plagioclase is An75–50. Ferrogabbro and diorite blocks have ∼ 3–5 wt.% MgO (TiO2 3.2–5.4%; K2O 0.8–1.3%; La 16–27 ppm), and a diorite vein is the most evolved (SiO2 59%, K2O 1.5%, La 38 ppm). They have clinopyroxene Mg#s 67–46, and plagioclase An57–40. The open-textured dunite has olivine ∼ Fo83.5. Seven isotope ratios are 87Sr/86Sr 0.70394–0.70374 and 143Nd/144Nd 0.51293–0.51286, and identify the suite as belonging to the Mauna Loa system. Gabbronorites and gabbros originated in solidification zones of Moku'aweoweo lava lakes where they acquired orthocumulate textures and incompatible-element depletions. These features suggest deeper and slower cooling lakes than the lava lake paradigm, Kilauea Iki, which is basalt and picrite. Clinopyroxene geobarometry suggests crystallization at < 1 kbar P. Highly evolved mineral Mg#s, < 75, are largely explained by cumulus phases exposed to evolving intercumulus liquids causing compositional ‘shifts.’ Ferrogabbro and diorite represent segregation veins from differentiated intercumulus liquids filter pressed into rigid zones of cooling lakes. Clinopyroxene geobarometry suggests < 300 bar P. Open-textured dunite represents olivine-melt mush, precursor to vertical olivine-rich bodies (as in Kilauea Iki). Its Fo83.5 identifies the most primitive lake magma as ∼ 8.3 wt.% MgO. Mass balancing and MELTS show that such a magma could have yielded both ferrogabbro and diorite by ≥ 50% fractional crystallization, but under different fO2: < FMQ (250 bar) led to diorite, and FMQ (250 bar) yielded ferrogabbro. These segregation veins, documented as similar to those of Kilauea, testify to appreciable volumes of ‘rhyolitic’ liquid forming in oceanic environments. Namely, SiO2-rich veins are intrinsic to all shields that reached caldera stage to accommodate various-sized cooling, differentiating lava lakes. DA - 2006/9// PY - 2006/9// DO - 10.1016/j.lithos.2006.03.005 VL - 90 IS - 3-4 SP - 187-213 SN - 0024-4937 KW - Mauna Loa KW - Lava lake KW - gabbronorite KW - mineral compositions KW - segregation veins KW - cumulate texture KW - Kilauea Iki ER - TY - JOUR TI - Modeling study of the influences of tide and stratification on age of water in the tidal James River AU - Shen, J. AU - Lin, J. T2 - Estuarine, Coastal and Shelf Science DA - 2006/// PY - 2006/// DO - 10.1016/j.eccs.2006.01.014 VL - 68 IS - 1-2 SP - 101-112 ER - TY - JOUR TI - Modeled Karenia brevis accumulation in the vicinity of a coastal nutrient front AU - Janowitz, Gerald S. AU - Kamykowski, Daniel 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 314:49-59 (2006) - doi:10.3354/meps314049 Modeled Karenia brevis accumulation in the vicinity of a coastal nutrient front Gerald S. Janowitz*, Daniel Kamykowski 1125 Jordan Hall, Department of Marine, Earth & Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695-8208, USA *Email: janowitz@ncsu.edu ABSTRACT: The alongshore independent distribution of Karenia brevis, a dominant harmful algal bloom dinoflagellate in the Gulf of Mexico, was investigated in a shelf environment using the Expanded Eulerian physical-biological modeling approach. The physical model included an ocean of variable depth with a frontal region at the 25 m isobath, and moderate upwelling-favorable winds. Nutrients were available from a surface source conceptually associated with outwelling from Florida bays, and from a near bottom offshore source conceptually associated with upwelling or sediment flux. The biological model included physiological rate processes, biochemical quotas, and behavioral responses based on cellular optimization and environmental conditions. The population distribution at the end of a 37 d simulation was examined. It was found that cells accumulated in the vicinity of the nearshore front. This accumulation began as soon as cells arrived near the front from the offshore boundary. Approximately 70% of the population was concentrated in the vicinity of the front by the end of the simulation. The trapping mechanism was interpreted to be a combination of fluid advection and swimming behavior. Four additional 37 d simulations were performed, where: (1) offshore bottom nutrient source was eliminated, (2) wind stress was doubled, (3) inhibition control on swimming behavior was imposed, and (4) chemotaxis control on swimming behavior was eliminated. Comparison of results from the simulations indicated that chemotaxis can play an important role in frontal accumulation. KEY WORDS: Model · Population dynamics · Dinoflagellate · Behavior Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 314. Online publication date: May 22, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research. DA - 2006/// PY - 2006/// DO - 10.3354/meps314049 VL - 314 SP - 49-59 SN - 0171-8630 KW - model KW - population dynamics KW - dinoflagellate KW - behavior ER - TY - JOUR TI - A quantitative real-time RT-PCR assay to measure TGF-β mRNA and its correlation with hematologic, plasma chemistry and organo-somatic indices responses in triamcinolone-treated Atlantic menhaden, Brevoortia tyrannus AU - Johnson, A.K. AU - Harms, C.A. AU - Levine, J.F. AU - Law, J. McHugh T2 - Developmental & Comparative Immunology AB - A quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) assay was developed to measure transforming growth factor-beta (TGF-beta) in Atlantic menhaden (Brevoortia tyrannus), an estuarine-dependent species plagued by ulcerative skin lesions in the estuaries along the eastern United States. Atlantic menhaden were acclimated in a closed system for two weeks prior to initiation of the study. The synthetic glucocorticoid, triamcinolone acetonide (10mg/kg body weight) was administered by intracoelomic injection and its effect on the splenic mononuclear cell TGF-beta mRNA transcription, liver-somatic index, spleno-somatic index, hematology, and plasma chemistry were compared to untreated fish at 48 and 96h post-treatment. Triamcinolone-treated Atlantic menhaden showed suppression of TGF-beta mRNA production, neutrophilia, monocytosis, lymphopenia, and an increase in blood glucose concentrations. The health indices used in this study may help us interpret some of the changes observed during the development of ulcerative skin lesions in wild-caught menhaden. DA - 2006/1// PY - 2006/1// DO - 10.1016/j.dci.2005.06.021 VL - 30 IS - 5 SP - 473-484 J2 - Developmental & Comparative Immunology LA - en OP - SN - 0145-305X UR - http://dx.doi.org/10.1016/j.dci.2005.06.021 DB - Crossref KW - Atlantic menhaden KW - triamcinolone KW - TGF-beta KW - health indices KW - hematology KW - plasma chemistry KW - real-time RT-PCR ER - TY - JOUR TI - Toward an emerging consensus on the ecology of Pfiesteria AU - Glibert, Patricia M. AU - Burkholder, JoAnn M. T2 - HARMFUL ALGAE DA - 2006/9// PY - 2006/9// DO - 10.1016/j.hal.2006.05.002 VL - 5 IS - 4 SP - 339-341 SN - 1568-9883 ER - TY - JOUR TI - Taxonomy of Pfiesteria (Dinophyceae) AU - Marshall, Harold G. AU - Hargraves, Paul E. AU - Burkholder, JoAnn M. AU - Parrow, Matthew W. AU - Elbraechter, Malte AU - Allen, Elle H. AU - Knowlton, Valerie M. AU - Rublee, Parke A. AU - Hynes, Wayne L. AU - Egerton, Todd A. AU - Remington, David L. AU - Wyatt, K. B. AU - Lewitus, Alan J. AU - Henrich, Vince C. T2 - HARMFUL ALGAE AB - The dinoflagellate species originally described as Pfiesteria shumwayae Glasgow et Burkholder, recently transferred to a new genus, Pseudopfiesteria Litaker et al., is reclassified into the redefined genus Pfiesteria Steidinger et Burkholder, as Pfiesteria shumwayae within the order Peridiniales. This change is based upon consideration of a compilation of previous and new morphological analyses and molecular phylogenetic analyses. Morphological analysis with scanning and transmission electron microscopy supports previous findings except in the sulcal area. In the cells examined, the sulcus is partly concealed by the peduncle cover plate (p.c.), which originates at the right side of the sulcus along the left side of the 6c and 5‴ plates. The fine structure of the p.c. appears similar to that of other thecal plates. The 1″ plate can also extend slightly over the sulcus. Transmission electron microscopy revealed that Pfiesteria shumwayae can have at least six sulcal plates; the number remains uncertain and may vary. The sulcal plates of this small, delicately thecate species have not been clearly discerned by scanning electron microscopy of membrane-stripped and/or suture-swollen cells. The Kofoidian thecal plate formula for the genus Pfiesteria is Po, cp, X, 4′, la, 5–6″, 6c, p.c., ?s, 5‴, 0p, 2‴′. The monophyletic grouping of “pfiesteria-like” taxa within the order Peridiniales, as well as the grouping of Pfiesteria piscicida and Pfiesteria shumwayae within the same genus, is also supported by the preponderance of previous molecular evidence, and by the phylogenetic trees contributed in the present analysis. Pfiesteria appears to be closely related to as-yet informally described cryptoperidiniopsoids and calcareous dinoflagellates such as Thoracosphaera; thus, the family classification requires revision that is beyond the scope of this study. DA - 2006/10// PY - 2006/10// DO - 10.1016/j.hal.2006.05.001 VL - 5 IS - 5 SP - 481-496 SN - 1878-1470 KW - Pfiesteria KW - Pfiesteria shumwayae KW - electron microscopy KW - morphology KW - plate tabulation KW - ribosomal genes KW - phylogenetic trees KW - taxonomy KW - toxigenic ER - TY - JOUR TI - Spatial association between speciated fine particles and mortality AU - Fuentes, Montserrat AU - Song, Hae-Ryoung AU - Ghosh, Sujit K. AU - Holland, David M. AU - Davis, Jerry M. T2 - BIOMETRICS AB - Particulate matter (PM) has been linked to a range of serious cardiovascular and respiratory health problems, including premature mortality. The main objective of our research is to quantify uncertainties about the impacts of fine PM exposure on mortality. We develop a multivariate spatial regression model for the estimation of the risk of mortality associated with fine PM and its components across all counties in the conterminous United States. We characterize different sources of uncertainty in the data and model the spatial structure of the mortality data and the speciated fine PM. We consider a flexible Bayesian hierarchical model for a space-time series of counts (mortality) by constructing a likelihood-based version of a generalized Poisson regression model that combines methods for point-level misaligned data and change of support regression. Our results seem to suggest an increase by a factor of two in the risk of mortality due to fine particles with respect to coarse particles. Our study also shows that in the Western United States, the nitrate and crustal components of the speciated fine PM seem to have more impact on mortality than the other components. On the other hand, in the Eastern United States, sulfate and ammonium explain most of the fine PM effect. DA - 2006/9// PY - 2006/9// DO - 10.1111/j.1541-0420.2006.00526.x VL - 62 IS - 3 SP - 855-863 SN - 1541-0420 KW - ambient air pollution KW - Bayesian hierarchical models KW - conditional autoregressive models KW - environmental epidemiology KW - particulate matter KW - spatial statistics ER - TY - JOUR TI - Real-time landscape model interaction using a tangible geospatial modeling environment AU - Mitasova, Helena AU - Mitas, Lubos AU - Ratti, Carlo AU - Ishii, Hiroshi AU - Alonso, Jason AU - Harmon, Russell S. T2 - IEEE COMPUTER GRAPHICS AND APPLICATIONS AB - Emerging technologies that combine the flexibility of digital landscape representation with easy-to-interpret 3D physical models open new possibilities for user interaction with geospatial data. A prototype tangible geospatial modeling environment lets users interact with landscape analysis and simulations using a tangible physical model. We introduce a concept that builds upon previous independent tangible user interface (TUI) and terrain analysis research and aims at more intuitive collaborative interaction with digital landscape data. DA - 2006/// PY - 2006/// DO - 10.1109/MCG.2006.87 VL - 26 IS - 4 SP - 55-63 SN - 1558-1756 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33746079196&partnerID=MN8TOARS ER - TY - JOUR TI - Phytoplankton and cloudiness in the Southern Ocean AU - Meskhidze, Nicholas AU - Nenes, Athanasios T2 - SCIENCE AB - The effect of ocean biological productivity on marine clouds is explored over a large phytoplankton bloom in the Southern Ocean with the use of remotely sensed data. Cloud droplet number concentration over the bloom was twice what it was away from the bloom, and cloud effective radius was reduced by 30%. The resulting change in the short-wave radiative flux at the top of the atmosphere was -15 watts per square meter, comparable to the aerosol indirect effect over highly polluted regions. This observed impact of phytoplankton on clouds is attributed to changes in the size distribution and chemical composition of cloud condensation nuclei. We propose that secondary organic aerosol, formed from the oxidation of phytoplankton-produced isoprene, can affect chemical composition of marine cloud condensation nuclei and influence cloud droplet number. Model simulations support this hypothesis, indicating that 100% of the observed changes in cloud properties can be attributed to the isoprene secondary organic aerosol. DA - 2006/12/1/ PY - 2006/12/1/ DO - 10.1126/science.1131779 VL - 314 IS - 5804 SP - 1419-1423 SN - 1095-9203 ER - TY - JOUR TI - Phosphatase activity in the heterotrophic dinoflagellate Pfiesteria shumwayae AU - Skelton, Hayley M. AU - Parrow, Matthew W. AU - Burkholder, JoAnn M. T2 - HARMFUL ALGAE AB - The ELF-97 phosphatase substrate was used to examine phosphatase activity in four strains of the estuarine heterotrophic dinoflagellate, Pfiesteria shumwayae. Acid and alkaline phosphatase activities also were evaluated at different pH values using bulk colorimetric methods. Intracellular phosphatase activity was demonstrated in P. shumwayae cells that were actively feeding on a fish cell line and in food limited cells that had not fed on fish cells for 3 days. All strains, whether actively feeding or food limited showed similar phosphatase activities. P. shumwayae cells feeding on fish cells showed ELF-97 activity near, or surrounding, the food vacuole. Relatively small, spherical ELF-97 deposits were also observed in the cytoplasm and sometimes near the plasma membrane. ELF-97 fluorescence was highly variable among cells, likely reflecting different stages in digestion and related metabolic processes. The location of enzyme activity and supporting colorimetric measurements suggest that, as in other heterotrophic protists, acid phosphatases predominate in P. shumwayae and have a general catabolic function. DA - 2006/9// PY - 2006/9// DO - 10.1016/j.hal.2006.04.010 VL - 5 IS - 4 SP - 395-406 SN - 1878-1470 KW - acid phosphatase KW - alkaline phosphatase KW - dinoflagellate KW - ELF-97 KW - heterotroph KW - Pfiesteria shumwayae ER - TY - JOUR TI - Pfiesteria piscicida and Pfiesteria shumwayae in coastal waters of Long Island, New York, USA AU - Rublee, Parke A. AU - Nuzzi, Robert AU - Waters, Robert AU - Schaefer, Eric F. AU - Burkholder, JoAnn A. T2 - HARMFUL ALGAE AB - Water and sediment samples were collected during summer and early fall 1999–2004 from coastal waters of New York State, USA, to test for the presence of Pfiesteria piscicida and Pfiesteria shumwayae. Physical and chemical conditions were characterized, and real-time polymerase chain reaction assays were conducted. Both species were relatively common and found at most sites at least once, and the frequency of positive assays was higher in sediments than in the water column. In a subset of the data from Suffolk County, Long Island, the presence of Pfiesteria was related to high chlorophyll a and relatively high nutrient concentrations. Partial SSU rDNA sequences of four PCR amplicons generated using P. shumwayae primers indicated two sequences: three were identical to GenBank P. shumwayae entries, but one showed enough sequence difference (15 positions in a 454 bp amplicon) to suggest a possible new species. Three isolates were tested for toxicity, and one was found to kill fish in bioassays. Despite the widespread presence of both Pfiesteria species and demonstration of potential to harm fish, no blooms of these dinoflagellates have been observed, nor has there been evidence of Pfiesteria-related fish or human health problems in these waters, likely related to colder temperatures than optimal for Pfiesteria species. DA - 2006/9// PY - 2006/9// DO - 10.1016/j.hal.2006.03.007 VL - 5 IS - 4 SP - 374-379 SN - 1878-1470 KW - dinoflagellates KW - Long Island KW - New York KW - Pfiesteria ER - TY - JOUR TI - Neoproterozoic and Cambrian arc magmatism along the eastern margin of the Victoria Lake Supergroup: A remnant of Ganderian basement in central Newfoundland? AU - Rogers, N. AU - Staal, C. R. AU - McNicoll, V. AU - Pollock, J. AU - Zagorevski, A. AU - Whalen, J. T2 - PRECAMBRIAN RESEARCH AB - The eastern margin of the composite and structurally complex Victoria Lake Supergroup has previously been mapped where the Silurian Rogerson Lake conglomeratic rocks unconformably overlie Cambrian Tally Pond volcanic rocks. However, the recognition that the form of this contact changes between an unconformity and a brittle-ductile fault, in conjunction with the Neoproterozoic age of the Crippleback Intrusive Suite, dictate that the above interpretation of the nature of this margin requires revision. These discrepancies are resolved by the recognition of a Neoproterozoic, largely bimodal volcanic sequence (Sandy Brook Group), which is unconformably overlain by Rogerson Lake rocks to the east, with these combined units in fault contact with the Tally Pond Group to the west. The Sandy Brook Group and Crippleback Intrusive Suite form a terrane of ca. 563 Ma rocks with continental arc-like geochemical signatures. The distinctly negative ɛNd,563 values for the felsic rocks (mean −3) of this terrane imply derivation from a crystalline basement older than the largely Pan-African crust that underlies contemporaneous volcanic rocks in West Avalonia, but similar to that inferred for the Gander Zone. Thus this terrane is likely to be the leading edge of the peri-Gondwanan microcontinent Ganderia. The ca. 511 Ma Tally Pond Group arc magmatism represent some of the oldest products of Iapetean subduction in Newfoundland. Although the Tally Pond Group are only observed to be in fault contact with the ca. 50 million year older Sandy Brook Group, the high proportion of felsic volcanic rocks, Sandy Brook/Crippleback age inherited zircons and Pb isotopic data all support the inference that the Tally Pond Group was formed on Sandy Brook/Crippleback continental crust. DA - 2006/7/5/ PY - 2006/7/5/ DO - 10.1016/j.precamres.2006.01.025 VL - 147 IS - 3-4 SP - 320-341 SN - 1872-7433 KW - Newfoundland KW - Ganderia KW - Avalonia KW - Neoproterozoic KW - tectonic reconstructions ER - TY - JOUR TI - Insight into the evolution of avian flight from a new clade of Early Cretaceous ornithurines from China and the morphology of Yixianornis grabaui AU - Clarke, JA AU - Zhou, ZH AU - Zhang, FC T2 - JOURNAL OF ANATOMY AB - In studies of the evolution of avian flight there has been a singular preoccupation with unravelling its origin. By contrast, the complex changes in morphology that occurred between the earliest form of avian flapping flight and the emergence of the flight capabilities of extant birds remain comparatively little explored. Any such work has been limited by a comparative paucity of fossils illuminating bird evolution near the origin of the clade of extant (i.e. 'modern') birds (Aves). Here we recognize three species from the Early Cretaceous of China as comprising a new lineage of basal ornithurine birds. Ornithurae is a clade that includes, approximately, comparatively close relatives of crown clade Aves (extant birds) and that crown clade. The morphology of the best-preserved specimen from this newly recognized Asian diversity, the holotype specimen of Yixianornis grabaui Zhou and Zhang 2001, complete with finely preserved wing and tail feather impressions, is used to illustrate the new insights offered by recognition of this lineage. Hypotheses of avian morphological evolution and specifically proposed patterns of change in different avian locomotor modules after the origin of flight are impacted by recognition of the new lineage. The complete articulated holotype specimen of Yixianornis grabaui, from the Early Cretaceous Jiufotang Formation of Liaoning Province, in north-eastern China, arguably the best-preserved basal ornithurine specimen yet discovered, provides the earliest evidence consistent with the presence of extant avian tail feather fanning. DA - 2006/3// PY - 2006/3// DO - 10.1111/j.1469-7580.2006.00534.x VL - 208 IS - 3 SP - 287-308 SN - 1469-7580 KW - birds KW - flight KW - morphological evolution KW - Ornithurae ER - TY - JOUR TI - Influence of seasonal primary productivity on delta C-13 of North Atlantic deep-sea benthic foraminifera AU - Corliss, B. H. AU - Sun, X. AU - Brown, C. W. AU - Showers, W. J. T2 - DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS AB - The stable isotopic composition of benthic foraminifera has been widely used to reconstruct deep-ocean circulation, but questions have been raised about the influence of organic carbon flux on the carbon isotopic composition of deep-sea taxa. We show that annual and seasonality of primary productivity in the North Atlantic do not affect δ13C of Planulina wuellerstorfi, but that the intermittency or seasonality of primary production has a significant effect (0.9‰ change over 60° latitude) on δ13C of Epistominella exigua, reflecting the influence of pelagic-benthic coupling and microhabitat preferences on test geochemistry. These results support the use of δ13C of P. wuellerstorfi in paleocirculation studies and suggest that the δ13C of E. exigua can be used to reconstruct seasonality of productivity. DA - 2006/4// PY - 2006/4// DO - 10.1016/j.dsr.2006.01.006 VL - 53 IS - 4 SP - 740-746 SN - 1879-0119 KW - benthic KW - foraminifera KW - deep-sea KW - paleoceanography KW - North Atlantic ER - TY - JOUR TI - Grazing activity of Pfiesteria piscicida (Dinophyceae) and susceptibility to ciliate predation vary with toxicity status AU - Lewitus, Alan J. AU - Wetz, Michael S. AU - Willis, Bonnie M. AU - Burkholder, JoAnn M. AU - Parrow, Matthew W. AU - Glasgow, Howard B. T2 - HARMFUL ALGAE AB - Variability has been reported in the toxicity potential of Pfiesteria piscicida that is partly a function of the history of exposure to live fish. Grazing properties of P. piscicida and its susceptibility to ciliate predation were compared in three functional types or toxicity states of this species: actively toxic cultures, cultures with temporary loss of demonstrable toxicity, and cultures with no demonstrable toxicity. Pronounced differences in predator–prey interactions were found between actively toxic cultures and cultures with reduced toxicity. When grown with Rhodomonas sp. (Cryptophyceae) prey, specific growth rates were relatively low in actively toxic cultures under both relatively high and low irradiances. In the cultures with reduced toxicity, prey chloroplast material was apparent in nearly 100% of dinoflagellate cells 3 h after feeding, while chloroplast inclusions were found in <40% of actively toxic cells for ≤16 h (high light) and ≤23 h (low light). These results suggest a relatively high reliance on phagotrophic carbon assimilation and more rapid response to algal prey availability in Pfiesteria cells with lower toxicity. Grazing by two euplotid benthic ciliates (Euplotes vannus and E. woodruffi) on P. piscicida also varied among functional types. Grazing on actively toxic P. piscicida cells did not occur, whereas net positive ingestion rates were calculated for the other prey cultures. These results support concurrent experimental findings that a natural assemblage of microzooplankton displayed lower grazing potential on actively toxic P. piscicida than on cultures with reduced toxicity. In summary, pronounced differences in trophic interactions were found between actively toxic cultures and those with reduced or undetectable toxicity, providing additional evidence of the importance of cellular toxicity in the trophic ecology of Pfiesteria. DA - 2006/9// PY - 2006/9// DO - 10.1016/j.hal.2006.04.012 VL - 5 IS - 4 SP - 427-434 SN - 1878-1470 KW - cryptophytes KW - grazing KW - microzooplankton KW - Pfiesteria piscicida KW - toxicity status ER - TY - JOUR TI - Effects of the estuarine dinoflagellate Pfiesteria shumwayae (Dinophyceae) on survival and grazing activity of several shellfish species AU - Shumway, Sandra E. AU - Burkholder, JoAnn M. AU - Springer, Jeffrey T2 - HARMFUL ALGAE AB - A series of experiments was conducted to examine effects of four strains of the estuarine dinoflagellate, Pfiesteria shumwayae, on the behavior and survival of larval and adult shellfish (bay scallop, Argopecten irradians; eastern oyster, Crassostrea virginica; northern quahogs, Mercenaria mercenaria; green mussels, Perna viridis [adults only]). In separate trials with larvae of A. irradians, C. virginica, and M. mercenaria, an aggressive predatory response of three strains of algal- and fish-fed P. shumwayae was observed (exception, algal-fed strain 1024C). Larval mortality resulted primarily from damage inflicted by physical attack of the flagellated cells, and secondarily from Pfiesteria toxin, as demonstrated in larval C. virginica exposed to P. shumwayae with versus without direct physical contact. Survival of adult shellfish and grazing activity depended upon the species and the cell density, strain, and nutritional history of P. shumwayae. No mortality of the four shellfish species was noted after 24 h of exposure to algal- or fish-fed P. shumwayae (strains 1024C, 1048C, and CCMP2089) in separate trials at ≤5 × 103 cells ml−1, whereas higher densities of fish-fed, but not algal-fed, populations (>7–8 × 103 cells ml−1) induced low (≤15%) but significant mortality. Adults of all four shellfish species sustained >90% mortality when exposed to fish-fed strain 270A1 (8 × 103 cells ml−1). In contrast, adult M. mercenaria and P. viridis exposed to a similar density of fish-fed strain 2172C sustained <15% mortality, and there was no mortality of A. irradians and C. virginica exposed to that strain. In mouse bioassays with tissue homogenates (adductor muscle, mantle, and whole animals) of A. irradians and M. mercenaria that had been exposed to P. shumwayae (three strains, separate trials), mice experienced several minutes of disorientation followed by recovery. Mice injected with tissue extracts from control animals fed cryptomonads showed no response. Grazing rates of adult shellfish on P. shumwayae (mean cell length ±1 standard error [S.E.], 9 ± 1 μm) generally were significantly lower when fed fish-fed (toxic) populations than when fed populations that previously had been maintained on algal prey, and grazing rates were highest with the nontoxic cryptomonad, Storeatula major (cell length 7 ± 1 μm). Abundant cysts of P. shumwayae were found in fecal strands of all shellfish species tested, and ≤45% of the feces produced viable flagellated cells when placed into favorable culture conditions. These findings were supported by a field study wherein fecal strands collected from field-collected adult shellfish (C. virginica, M. mercenaria, and ribbed mussels, Geukensia demissa) were confirmed to contain cysts of P. shumwayae, and these cysts produced fish-killing flagellated populations in standardized fish bioassays. Thus, predatory feeding by flagellated cells of P. shumwayae can adversely affect survival of larval bivalve molluscs, and grazing can be depressed when adult shellfish are fed P. shumwayae. The data suggest that P. shumwayae could affect recruitment of larval shellfish in estuaries and aquaculture facilities; shellfish can be adversely affected via reduced filtration rates; and adult shellfish may be vectors of toxic P. shumwayae when shellfish are transported from one geographic location to another. DA - 2006/9// PY - 2006/9// DO - 10.1016/j.hal.2006.04.013 VL - 5 IS - 4 SP - 442-458 SN - 1878-1470 KW - Argopecten irradians KW - Crassostrea virginica KW - cyst KW - dinoflagellate KW - grazing KW - Geukensia demissa KW - Mercenaria mercenaria KW - Perna viridis KW - Pfiesteria shumwayae KW - shellfish KW - toxigenic ER - TY - JOUR TI - Dissolved oxygen stratification in two micro-tidal partially-mixed estuaries AU - Lin, Jing AU - Xie, Lian AU - Pietrafesa, Len J. AU - Shen, Jian AU - Mallin, Michael A. AU - Durako, Michael J. T2 - ESTUARINE COASTAL AND SHELF SCIENCE AB - The controlling physical factors for vertical oxygen stratification in micro-tidal, partially-mixed estuaries are discussed in this paper. A theoretical deduction shows that vertical stratification of dissolved oxygen (DO) concentration can be explained by the extended Hansen and Rattray's Central Region theory, which suggests that in addition to biological factors such as photosynthesis, biochemical oxygen demand (BOD), sediment oxygen demand (SOD), vertical DO profiles are mainly controlled by physical factors such as surface re-aeration, river flow, and estuarine gravitational circulation. Vertical mixing of DO from surface re-aeration and photosynthesis sets a DO profile of higher concentration near the surface and lower near the bottom. With a positive seaward longitudinal DO gradient, strong river flow and estuarine gravitational circulation can cause lower DO concentrations near the surface and higher near the bottom. The actual vertical oxygen profile is then determined by the relative magnitude of the above-mentioned mechanisms. It is sensitive to two parameters: (1) the strength of the gravitational circulation (uE); and (2) the relative importance between biochemical oxygen demand and vertical diffusivity (α). Vertical DO stratification usually becomes weaker as uE increases. The impact of gravitational circulation on vertical oxygen distribution becomes more important for a larger α. The impact of α on oxygen stratification is profound. As uE (and river flow) increases, DO stratification appears to be less sensitive to the value of α. Surface-to-bottom differences in DO concentrations (ΔDO) is negligible when α is small (α < 0.5). As α increases, ΔDO increases under a weak to moderate gravitational circulation mode (uE ≤ 5 cm s−1). Under a strong gravitational circulation mode, ΔDO becomes negative with a small α (α < 2), and as α continues to increase, ΔDO becomes positive. The newly-deduced governing equation for vertical oxygen stratification is applied to two micro-tidal, partially-mixed estuarine systems: the Cape Fear River Estuary (CFRE) and the Pamlico River Estuary (PRE) of North Carolina. In the CFRE, although strong vertical salinity stratification exists, DO concentrations are usually well mixed. De-coupling between salinity stratification and oxygen stratification is mainly due to a relatively stronger estuarine gravitational circulation and higher freshwater inflow in the system. It appears that river flow and gravitational circulation are the dominant factors in controlling oxygen stratification in the CFRE. In contrast, vertical stratification of DO concentrations is closely correlated with that of salinity in the PRE. In the PRE, the estuarine gravitational mode and river flow are often both very weak, and DO stratification is very sensitive to the value of α. With negligible influence from tidal mixing, the system is more sensitive to vertical mixing regulated by salinity stratification and wind. As a result, vertical DO stratification is closely correlated with salinity stratification in the PRE. DA - 2006/11// PY - 2006/11// DO - 10.1016/j.ecss.2006.06.032 VL - 70 IS - 3 SP - 423-437 SN - 1096-0015 KW - dissolved oxygen KW - stratification KW - estuarine gravitational circulation KW - vertical mixing KW - Cape Fear River KW - Pamlico River ER - TY - JOUR TI - Direct uptake of nitrogen by Pfiesteria piscicida and Pfiesteria shumwayae, and nitrogen nutritional preferences AU - Glibert, Patricia M. AU - Burkholder, JoAnn M. AU - Parrow, Matthew W. AU - Lewitus, Alan J. AU - Gustafson, Daniel E. T2 - HARMFUL ALGAE AB - The rates of uptake of a range of forms of nitrogenous nutrients were measured in cultures of Pfiesteria piscicida and Pfiesteria shumwayae maintained at varying physiological states. The measured rates of dissolved N uptake under some conditions approached the rates of N uptake that are achieved through phagotrophy. Rates of dissolved N uptake by P. piscicida contributed <10% of the cellular N of flagellated cells feeding on algae, but were equal to or greater than phagotrophic N acquisition in cells recently removed from fish cultures. Specific N uptake rates (V, h−1) were higher for cells that were maintained on algal prey for long periods (months) than those that were grown with live fish. However, rates of N uptake on a cellular basis for cells grown on or recently removed from fish were comparable to those maintained on algal prey, likely reflecting differences in the sizes of cells of different physiological condition. Preferences for form of N generally followed a decreasing trend of amino acids > urea > NH4+ > NO3−. Nitrate consistently was not a preferred form of N. Although Pfiesteria spp. are often found in eutrophic environments, the relationship between Pfiesteria spp. and nutrient availability is likely to be primarily indirect, mediated through the production of various prey on which Pfiesteria spp. feed. These findings also confirm, however, that when dissolved N concentrations are elevated, they can contribute to the supplemental nutrition of these cells, and thus may provide a significant source of N to Pfiesteria spp. in nature. DA - 2006/9// PY - 2006/9// DO - 10.1016/j.hal.2006.04.009 VL - 5 IS - 4 SP - 380-394 SN - 1878-1470 KW - Pfiesteria KW - nitrogen nutrition KW - heterotrophy KW - toxigenic dinoflagellates ER - TY - JOUR TI - Comprehensive trend analysis of nutrients and related variables in a large eutrophic estuary: A decadal study of anthropogenic and climatic influences AU - Burkholder, JoAnn M. AU - Dickey, David A. AU - Kinder, Carol A. AU - Reed, Robert E. AU - Mallin, Michael A. AU - McIver, Matthew R. AU - Cahoon, Lawrence B. AU - Melia, Greg AU - Brownie, Cavell AU - Smith, Joy AU - Deamer, Nora AU - Springer, Jeffrey AU - Glasgow, Howard B. AU - Toms, David T2 - LIMNOLOGY AND OCEANOGRAPHY AB - We used a decadal data set, with weekly to biweekly sampling in April—October and monthly sampling in November—March, to characterize climatic (hurricane‐level storms, a sustained 3‐yr drought) and anthropogenic influences on N and P concentrations and loadings to a large eutrophic, poorly flushed estuary, the Neuse Estuary of the Albemarle—Pamlico Estuarine System. Mass volume transport data were obtained with cross‐estuary transect flow measurements taken near the entrance to the estuary. Although trends were minimally influenced by hurricanes, analyses were significantly affected by the sustained drought near the end of the study. As examples, decreasing trends in total N (TN), total P (TP), and bottom‐water dissolved oxygen concentrations, and in TN loadings were significant considering all data, but these trends were not significant when the sustained drought was excluded from analysis. In addition, the trend in TN loading was especially sensitive to the initial sampling period. NH 4 + concentrations dramatically increased (overall by ~500%) as a persistent trend regardless of attempts to control for climatic events. An increasing trend in NH 4 + also was documented in an adjacent, rapidly flushed Coastal Plain estuary, the Cape Fear. The NH 4 + data suggest a regional‐scale effect of high inputs from inadequately controlled, increasing nonpoint sources. The fragility of TN loading trends, the striking increase in NH 4 + concentrations, and the lack of management emphasis on controlling nonpoint sources such as “new” industrialized swine production collectively do not support recent reports of achievement of a 30% reduction in TN loading to the Neuse. Nonpoint sources remain a critical target for reduction to alleviate the negative effects of cultural eutrophication in this system, as in many estuaries throughout the world. DA - 2006/1// PY - 2006/1// DO - 10.4319/lo.2006.51.1_part_2.0463 VL - 51 IS - 1 SP - 463-487 SN - 1939-5590 ER - TY - JOUR TI - Comparing the potential effectiveness of conservation planning approaches in central North Carolina, USA AU - Hess, GR AU - Koch, FH AU - Rubino, MJ AU - Eschelbach, KA AU - Drew, CA AU - Favreau, JM T2 - BIOLOGICAL CONSERVATION AB - We compared four approaches to conservation site selection to protect forest biodiversity in the Triangle Region of North Carolina, USA. Using biological inventory data and an inventory-based conservation plan as benchmarks, we evaluated the potential effectiveness of a focal species plan and three “simple” plans (large forested patches, close to wetlands and riparian areas, diverse forest types). Effectiveness was measured in three ways: the number of inventory elements captured at least once by the plan (representation), the total number of inventory elements captured (completeness), and the proportion of land in the inventory-based plan included (overlap). We further examined the potential effectiveness of the simple plans by calculating their overlap with land identified by the focal species approach. The simple and focal species plans did not differ markedly in terms of representation, but diverged when completeness and overlap were considered. Although representation rates for all four plans were relatively high, lower rates for completeness and overlap raise concerns about long-term viability. The simple plans did not identify the same lands as the focal species plan, and are thus unlikely to provide appropriate habitat for the focal species. Each approach we tested failed to capture some subset of species and communities, highlighting the importance of explicit conservation targets and consideration of ecological processes. Forced to act quickly and with little data, our findings suggest using initially a set of complementary simple plans, each focused on a different habitat type. This should be considered a stopgap measure, however, while more sophisticated plans are constructed, defining explicit conservation targets and considering ecological processes. DA - 2006/3// PY - 2006/3// DO - 10.1016/j.biocon.2005.10.003 VL - 128 IS - 3 SP - 358-368 SN - 1873-2917 KW - conservation planning KW - focal species KW - biological inventory data KW - reserve design KW - surrogate species KW - conservation targets ER - TY - JOUR TI - A synthesis of bentho-pelagic coupling on the Antarctic shelf: Food banks, ecosystem inertia and global climate change AU - Smith, Craig R. AU - Mincks, Sarah AU - DeMaster, David J. T2 - DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY AB - The Antarctic continental shelf is large, deep (500–1000 m), and characterized by extreme seasonality in sea-ice cover and primary production. Intense seasonality and short pelagic foodwebs on the Antarctic shelf may favor strong bentho-pelagic coupling, whereas unusual water depth combined with complex topography and circulation could cause such coupling to be weak. Here, we address six questions regarding the nature and strength of coupling between benthic and water-column processes on the continental shelf surrounding Antarctica. We find that water-column production is transmitted to the shelf floor in intense pulses of particulate organic matter, although these pulses are often difficult to correlate with local phytoplankton blooms or sea-ice conditions. On regional scales, benthic habitat variability resulting from substrate type, current regime, and iceberg scour often may obscure the imprint of water-column productivity on the seafloor. However, within a single habitat type, i.e. the muddy sediments that characterize much of the deep Antarctic shelf, macrobenthic biomass appears to be correlated with regional primary production and sea-ice duration. Over annual time-scales, many benthic ecological processes were initially expected to vary in phase with the extraordinary boom/bust cycle of production in the water column. However, numerous processes, including sediment respiration, deposit feeding, larval development, and recruitment, often are poorly coupled to the summer bloom season. Several integrative, time-series studies on the Antarctic shelf suggest that this lack of phasing may result in part from the accumulation of a persistent sediment food bank that buffers the benthic ecosystem from the seasonal variability of the water column. As a consequence, a variety of benthic parameters (e.g., sediment respiration, inventories of labile organic matter, macrobenthic biomass) may act as “low-pass” filters, responding to longer-term (e.g., inter-annual) trends in water-column production. Bentho-pelagic coupling clearly will be altered by Antarctic climate change as patterns of sea-ice cover and water-column recycling vary. However, the nature of such climate-driven changes will be very difficult to predict without further studies of Antarctic benthic ecosystem response to (1) inter-annual variability in export flux, and (2) latitudinal gradients in duration of sea-ice cover and benthic ecosystem function. DA - 2006/// PY - 2006/// DO - 10.1016/j.dsr2.2006.02.001 VL - 53 IS - 8-10 SP - 875-894 SN - 1879-0100 KW - Antarctic shelf KW - bentho-pelagic coupling KW - organic carbon flux KW - climate change KW - food banks KW - benthos ER - TY - JOUR TI - A multimodel assessment of RKW theory's relevance to squall-line characteristics AU - Bryan, George H. AU - Knievel, Jason C. AU - Parker, Matthew D. T2 - MONTHLY WEATHER REVIEW AB - Abstract The authors evaluate whether the structure and intensity of simulated squall lines can be explained by “RKW theory,” which most specifically addresses how density currents evolve in sheared environments. In contrast to earlier studies, this study compares output from four numerical models, rather than from just one. All of the authors’ simulations support the qualitative application of RKW theory, whereby squall-line structure is primarily governed by two effects: the intensity of the squall line’s surface-based cold pool, and the low- to midlevel environmental vertical wind shear. The simulations using newly developed models generally support the theory’s quantitative application, whereby an optimal state for system structure also optimizes system intensity. However, there are significant systematic differences between the newer numerical models and the older model that was originally used to develop RKW theory. Two systematic differences are analyzed in detail, and causes for these differences are proposed. DA - 2006/10// PY - 2006/10// DO - 10.1175/MWR3226.1 VL - 134 IS - 10 SP - 2772-2792 SN - 1520-0493 ER - TY - JOUR TI - A comprehensive performance evaluation of MM5-CMAQ for the summer 1999 southern oxidants study episode, Part III: Diagnostic and mechanistic evaluations AU - Zhang, Y. AU - Liu, P. AU - Pun, B. AU - Seigneur, C. T2 - Atmospheric Environment DA - 2006/// PY - 2006/// DO - 10.1016/j.atmonsenv.2005.12.046 VL - 40 IS - 26 SP - 4856-4873 ER - TY - JOUR TI - A comprehensive performance evaluation of MM5-CMAQ for the Summer 1999 Southern Oxidants Study episode- Part II: Gas and aerosol predictions AU - Zhang, Y. AU - Liu, P. AU - Queen, A. AU - Misenis, C. AU - Pun, B. AU - Seigneur, C. AU - Wu, S. Y. T2 - Atmospheric Environment DA - 2006/// PY - 2006/// DO - 10.1016/j.atmonsenv.2005.12.048 VL - 40 IS - 26 SP - 4839-4855 ER - TY - JOUR TI - A comprehensive performance evaluation of MM5-CMAQ for the Summer 1999 Southern Oxidants Study episode - Part I: Evaluation protocols, databases, and meteorological predictions AU - Zhang, Yang AU - Liu, Ping AU - Pun, Betty AU - Seigneur, Christian T2 - ATMOSPHERIC ENVIRONMENT AB - A comprehensive model evaluation has been conducted for MM5-CMAQ for the period of 1–10 July 1999 of the Southern Oxidants Study episode with a coarse-grid horizontal spacing of 32-km and a nested fine-grid spacing of 8-km. Meteorological and chemical predictions from simulations with both grids are compared with observations from both routine monitoring networks (e.g., CASTNet, IMPROVE, and AIRS-AQS) and special studies (e.g., SOS99/SOS99NASH, SEARCH, and ARIES). In this Part I paper, five simulated meteorological variables (i.e., temperature, relative humidity (RH), wind speed, wind direction, and planetary boundary layer (PBL) height) are evaluated. While MM5 reproduces well the diurnal variations for temperature and RH, and the minimum temperatures at all sites, it tends to overpredict maximum temperatures and underpredict both maximum and minimum RHs on most days at most sites. MM5 predictions agree reasonably well for wind speeds but poorly for wind direction and the maximum mixing depths. The significant overpredictions in the PBL heights can be attributed to the positive biases of the maximum 2-m temperatures and to the Medium Range Forecast (MRF) model PBL scheme and the Oregon State University (OSU)-Land Surface Model used in the MM5 simulations. For wind speed/direction and the U- and V-component of the wind speed, the normalized mean bias (NMB) and the normalized mean bias factor (NMBF) are the most robust statistical measures because of the dominance of the extremely small observed values in the normalization for those variables. DA - 2006/8// PY - 2006/8// DO - 10.1016/j.atmosenv.2005.12.043 VL - 40 IS - 26 SP - 4825-4838 SN - 1873-2844 KW - model evaluation KW - CMAQ KW - MM5 KW - SOS KW - statistical measures ER - TY - PAT TI - Variable depth automated dynamic water profiler AU - Glasgow, H., Jr. AU - Reed, R. E. AU - Toms, D. C. AU - Burkholder, J. C2 - 2006/// DA - 2006/// PY - 2006/// ER - TY - JOUR TI - The taxonomy and growth of a Crypthecodinium species (Dinophyceae) isolated from a brackish-water fish aquarium AU - Parrow, M. W. AU - Elbraechter, M. AU - Krause, M. K. AU - Burkholder, J. M. AU - Deamer, N. J. AU - Htyte, N. AU - Allen, E. H. T2 - AFRICAN JOURNAL OF MARINE SCIENCE AB - An unidentified heterotrophic dinoflagellate found growing in abundance in a brackish-water fish aquarium was isolated and serially cultivated using a fish cell line as the food source. Prominent characteristics of this dinoflagellate included a cingulum that did not fully encircle the motile cell, cell division in non-motile cysts, and a theca composed of thin but structured plates. Morphological analysis of flagellate cells by scanning electron microscopy revealed a Kofoid thecal plate tabulation of 4', 4a, 4", 'X', 5 or 6c, ?s, 5"', 1p, 1"", most consistent with the original description of Crypthecodinium setense Biecheler. This Crypthecodinium species exhibited a high maximum division rate (3.2 divisions day−1) and cell yield (>106 cells ml−1) when fed cultured fish cells. Small sub-unit rDNA phylogenetic analyses supported relatedness with a previously studied Crypthecodinium-like dinoflagellate, but a significant difference in aligned gene sequences was found. This study provides the first clear demonstration of the plate tabulation of a Crypthecodinium species since the original description over 60 years ago, allowing the original morphological conception of Crypthecodinium to be linked with molecular phylogenetic information. DA - 2006/9// PY - 2006/9// DO - 10.2989/18142320609504145 VL - 28 IS - 2 SP - 185-191 SN - 1814-232X KW - Crypthecodinium KW - dinoflagellate KW - phylogeny KW - small sub-unit rDNA KW - taxonomy KW - theca ER - TY - JOUR TI - The effects of physiology and behaviour on the near-bottom distributions of Karenia brevis on the West Florida shelf: a numerical study AU - Sinclair, G. A. AU - Kamykowski, D. T2 - AFRICAN JOURNAL OF MARINE SCIENCE AB - The distribution of near-bottom populations of Karenia brevis depends on both cell physiology and behaviour. The migration distance of cells, and the subsequent exposure to light, may vary as a result of the nocturnal uptake of nitrate. The adaptive advantage of higher nocturnal uptake rates and upward migration is evident in clear deep (90m) water columns as well as in shallower (30m), more turbid water columns. In deeper offshore environments, migrating cells with high nocturnal uptake rates are able to access light levels needed to compensate growth, whereas migrating cells with slow nocturnal uptake rates or non-migrating cells cannot access the minimum light levels needed for growth. In shallow, more turbid environments, migrating cells access between 35% and 67% of the light needed to saturate growth, whereas cells that do not migrate are only exposed to 6% of the light needed to saturate growth. Vertical migration may not only extend the depth distribution of K. brevis but also provide an adaptation to persist in more turbid nearshore waters. DA - 2006/9// PY - 2006/9// DO - 10.2989/18142320609504178 VL - 28 IS - 2 SP - 361-364 SN - 1814-2338 KW - diel vertical migration KW - dinoflagellate KW - nocturnal uptake KW - nutrient acquisition ER - TY - JOUR TI - Intraspecific variability: an important consideration in forming generalisations about toxigenic algal species AU - Burkholder, J. M. AU - Glibert, P. M. T2 - AFRICAN JOURNAL OF MARINE SCIENCE AB - Intraspecific variability (strain differences) in key characteristics such as life-history traits, behaviour, nutrition, genetics and toxicity, has been experimentally documented for many toxigenic microalgae, including species of cyanobacteria, dinoflagellates, haptophytes, raphidophytes and diatoms. This paper summarises findings from published studies on intraspecific variability in toxicity. The data show that different, often opposite, interpretations at the species level would have resulted from consideration of individual strains. A survey of recent literature on harmful algae revealed that intraspecific variation is still commonly overlooked in characterisations of these species and generalisations about their roles in foodwebs. The available data underscore the importance of including multiple strains in research to advance understanding about toxigenic algal species and the importance of tempering conclusions to consider the potential for differences beyond the strains studied. DA - 2006/9// PY - 2006/9// DO - 10.2989/18142320609504143 VL - 28 IS - 2 SP - 177-180 SN - 1814-232X KW - harmful algae KW - intraspecific variability KW - strains KW - toxigenic ER - TY - JOUR TI - Geomorphologic controls on the age of particulate organic carbon from small mountainous and upland rivers AU - Leithold, Elana L. AU - Blair, Neal E. AU - Perkey, David W. T2 - GLOBAL BIOGEOCHEMICAL CYCLES AB - To assess the role that erosion processes play in governing the character of particulate organic carbon (POC) discharged from small mountainous and upland rivers, a suite of watersheds from Oregon, California, and New Zealand was investigated. The rivers share similar geology, tectonic setting, and climate, but have sediment yields that range over 3 orders of magnitude. The 14 C age of the POC loads is highly correlated with sediment yield. Carbon isotope mass balances reveal that the rivers carry bimodal mixtures of modern‐plant‐ and ancient‐rock‐derived OC. At lower yields, modern plant OC dominates the material delivered to the river by sheetwash and shallow landsliding. With increasing yield, a progressively larger part of the POC is contributed directly from bedrock erosion via deep gully incision. Our results support the inference that active margin watersheds are important sources of aged POC to the ocean. DA - 2006/9/9/ PY - 2006/9/9/ DO - 10.1029/2005gb002677 VL - 20 IS - 3 SP - SN - 1944-9224 ER - TY - JOUR TI - Detrital zircon geochronology of the Smith River Allochthon and Lynchburg Group, southern Appalachians: Implications for Neoproterozoic-Early Cambrian paleogeography AU - Carter, Brad T. AU - Hibbard, James P. AU - Tubrett, Mike AU - Sylvester, Paul T2 - PRECAMBRIAN RESEARCH AB - A detrital zircon geochronological study was undertaken to provide insight into the Neoproterozoic-Early Cambrian paleo-continental affinity of the Smith River Allochthon (SRA). The SRA has been depicted by some authors to represent a distal facies equivalent of the Lynchburg Group, a rift-related sequence that originated along the Laurentian margin during the Neoproterozoic-Early Cambrian opening of the Iapetus Ocean. Other workers, however, have interpreted the SRA as being exotic with respect to Laurentia and possibly of Gondwanan origin. The most predominant detrital age population in both terranes ranges from 0.9 to 1.25 Ga. Both terranes also contain minor populations ranging from 0.75 to 0.9 Ga and 1.3 to 1.4 Ga. The SRA also contains a minor population ranging from 1.4 to 1.5 Ga. The youngest detrital zircon ages in both terranes are <900 Ma. Uranium (U) concentrations in the zircons were also determined. The U concentration versus age plot of the SRA samples is similar to that of the Lynchburg Group. The majority of the grains in both terranes contain less than 500 ppm U, with the Lynchburg Group zircons containing a higher mean U concentration than the SRA (307 ppm versus 226 ppm). The striking similarities of the detrital zircon age and chemical data for the SRA and Lynchburg Group samples suggest that the SRA and Lynchburg Group share a common provenance along the Laurentian margin. These data conflict with electron microprobe (EPMA) monazite geochronological data that document an Early Cambrian tectonothermal event in the SRA. The eastern Laurentian margin was in the rift-to-drift transition by the Early Cambrian, so a tectonothermal event along the Laurentian margin at this time is difficult to envision. Based on the striking similarities of the detrital zircon data, we suggest that the SRA is most likely a distal facies equivalent of the Lynchburg Group, and thus of Laurentian origin, even though it records an Early Cambrian tectonothermal event. This interpretation is consistent with some interpretations of peri-Laurentian affinity for other terranes in the Piedmont zone of the southern Appalachians. DA - 2006/7/5/ PY - 2006/7/5/ DO - 10.1016/j.precamres.2006.01.024 VL - 147 IS - 3-4 SP - 279-304 SN - 1872-7433 KW - Smith Rriver Allochthon KW - Lynchburg Group KW - Early Cambrian KW - eastern Laurentian margin KW - detrital zircon chemistry KW - southern Appalachians ER - TY - JOUR TI - Continental slope sea level and flow variability induced by lateral movements of the Gulf Stream in the Middle Atlantic Bight AU - Boehm, E. AU - Hopkins, T. S. AU - Pietrafesa, L. J. AU - Churchill, J. H. T2 - PROGRESS IN OCEANOGRAPHY AB - Abstract As described by [Csanady, G.T., Hamilton, P., 1988. Circulation of slope water. Continental Shelf Research 8, 565–624], the flow regime over the slope of the southern Middle Atlantic Bight (MAB) includes a current reversal in which southwestward flow over the upper and middle slope becomes entrained in the northeastward current adjacent to the Gulf Stream. In this paper we use satellite-derived data to quantify how lateral motions of the Gulf Stream impact this current system. In our analysis, the Gulf Stream’s thermal front is delineated using a two-year time series of sea surface temperature derived from NOAA/AVHRR satellite data. Lateral motions of the Gulf Stream are represented in terms of temporal variations of the area, east of 73°W, between the Gulf Stream thermal front and the shelf edge. Variations of slope water flow within this area are represented by anomalies of geostrophic velocity as derived from the time series of the sea level anomaly determined from TOPEX/POSEIDON satellite altimeter data. A strong statistical relationship is found between Gulf Stream displacements and parabathic flow over the continental slope. It is such that the southwestward flow over the slope is accelerated when the Gulf Stream is relatively far from the shelf edge, and is decelerated (and perhaps even reversed) when the Gulf Stream is close to the shelf edge. This relationship between Gulf Stream displacements and parabathic flow is also observed in numerical simulations produced by the Miami Isopycnic Coordinate Model. In qualitative terms, it is consistent with the notion that when the Gulf Stream is closer to the 200-m isobath, it is capable of entraining a larger fraction of shelf water masses. Alternatively, when the Gulf Stream is far from the shelf-break, more water is advected into the MAB slope region from the northeast. Analysis of the diabathic flow indicates that much of the cross-slope transport by which the southwestward flow entering the study region is transferred to the northeastward flow exiting the region occurs in a narrow band roughly centered at 36.75°N, order 150 km north of Cape Hatteras. This transport, and thus the cyclonic circulation of the southern MAB, strengthens when the Gulf Stream is relatively close to the shelf edge, and weakens when the Gulf Stream is far from the shelf edge. DA - 2006/// PY - 2006/// DO - 10.1016/j.pocean.2006.07.005 VL - 70 IS - 2-4 SP - 196-212 SN - 0079-6611 KW - sea level anomaly KW - sea surface temperature KW - satellite data KW - Gulf Stream KW - parabathic flow KW - shelf edge ER - TY - JOUR TI - Comparison of collocated automated (NCECONet) and manual (COOP) climate observations in North Carolina AU - Holder, C AU - Boyles, R AU - Syed, A AU - Niyogi, D AU - Raman, S T2 - JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY AB - Abstract The National Weather Service's Cooperative Observer Program (COOP) is a valuable climate data resource that provides manually observed information on temperature and precipitation across the nation. These data are part of the climate dataset and continue to be used in evaluating weather and climate models. Increasingly, weather and climate information is also available from automated weather stations. A comparison between these two observing methods is performed in North Carolina, where 13 of these stations are collocated. Results indicate that, without correcting the data for differing observation times, daily temperature observations are generally in good agreement (0.96 Pearson product–moment correlation for minimum temperature, 0.89 for maximum temperature). Daily rainfall values recorded by the two different systems correlate poorly (0.44), but the correlations are improved (to 0.91) when corrections are made for the differences in observation times between the COOP and automated stations. Daily rainfall correlations especially improve with rainfall amounts less than 50 mm day−1. Temperature and rainfall have high correlation (nearly 1.00 for maximum and minimum temperatures, 0.97 for rainfall) when monthly averages are used. Differences of the data between the two platforms consistently indicate that COOP instruments may be recording warmer maximum temperatures, cooler minimum temperatures, and larger amounts of rainfall, especially with higher rainfall rates. Root-mean-square errors are reduced by up to 71% with the day-shift and hourly corrections. This study shows that COOP and automated data [such as from the North Carolina Environment and Climate Observing Network (NCECONet)] can, with simple corrections, be used in conjunction for various climate analysis applications such as climate change and site-to-site comparisons. This allows a higher spatial density of data and a larger density of environmental parameters, thus potentially improving the accuracy of the data that are relayed to the public and used in climate studies. DA - 2006/5// PY - 2006/5// DO - 10.1175/jtech1873.1 VL - 23 IS - 5 SP - 671-682 SN - 0739-0572 ER - TY - JOUR TI - Climate variability over the Greater Horn of Africa based on NCAR AGCM ensemble AU - Anyah, R. O. AU - Semazzi, F. H. M. T2 - THEORETICAL AND APPLIED CLIMATOLOGY DA - 2006/9// PY - 2006/9// DO - 10.1007/s00704-005-0203-7 VL - 86 IS - 1-4 SP - 39-62 SN - 0177-798X ER - TY - JOUR TI - Characterization of major chemical components.of fine. particulate matter in North Carolina AU - Aneja, Viney P. AU - Wang, Binyu AU - Tong, Daniel Q. AU - Kimball, Hoke AU - Steger, Joette T2 - JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION AB - Abstract This paper presents measurements of daily sampling of fine particulate matter (PM2.5) and its major chemical components at three urban and one rural locations in North Carolina during 2002. At both urban and rural sites, the major insoluble component of PM2.5 is organic matter, and the major soluble components are sulfate (SO4 2−), ammonium (NH4 +), and nitrate (NO3 −). NH4 + is neutralized mainly by SO4 2− rather than by NO3 −, except in winter when SO4 2− concentration is relatively low, whereas NO3 − concentration is high. The equivalent ratio of NH4 + to the sum of SO4 2− and NO3 − is <1, suggesting that SO4 2−and NO3 −are not completely neutralized by NH4 +. At both rural and urban sites, SO4 2−concentration displays a maximum in summer and a minimum in winter, whereas NO3 −displays an opposite seasonal trend. Mass ratio of NO3 − to SO4 2−is consistently <1 at all sites, suggesting that stationary source emissions may play an important role in PM2.5 formation in those areas. Organic carbon and elemental carbon are well correlated at three urban sites although they are poorly correlated at the agriculture site. Other than the daily samples, hourly samples were measured at one urban site. PM2.5 mass concen trations display a peak in early morning, and a second peak in late afternoon. Back trajectory analysis shows that air masses with lower PM2.5 mass content mainly originate from the marine environment or from a continental environment but with a strong subsidence from the upper troposphere. Air masses with high PM2.5 mass concentrations are largely from continental sources. Our study of fine particulate matter and its chemical composition in North Carolina provides crucial information that may be used to determine the efficacy of the new National Ambient Air Quality Standard (NAAQS) for PM fine. Moreover, the gas-to-particle conversion processes provide improved prediction of long-range transport of pollutants and air quality. DA - 2006/8// PY - 2006/8// DO - 10.1080/10473289.2006.10464529 VL - 56 IS - 8 SP - 1099-1107 SN - 1047-3289 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33749151190&partnerID=MN8TOARS ER - TY - JOUR TI - Calculating a daily normal temperature range that reflects daily temperature variability AU - Holder, Christopher AU - Boyles, Ryan AU - Robinson, Peter AU - Raman, Sethli AU - Fishel, Greg T2 - BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY AB - Normal temperatures, which are calculated by the National Climatic Data Center for locations across the country, are quality-controlled, smoothed 30-yr-average temperatures. They are used in many facets of media, industry, and meteorology, and a given day's normal maximum and minimum temperatures are often used synonymously with what the observed temperature extremes “should be.” However, allowing some leeway to account for natural daily and seasonal variations can more accurately reflect the ranges of temperature that we can expect on a particular day—a “normal range.” Providing such a range, especially to the public, presents a more accurate perspective on what the temperature “usually” is on any particular day of the year. One way of doing this is presented in this study for several locations across North Carolina. The results yield expected higher variances in the cooler months and seem to well represent the varied weather that locations in North Carolina tend to experience. Day-to-day variations in the normal range are larger than expected, but are retained rather than smoothed. The method is simple and applicable to any location with a complete 30-yr record and with a temperature variance time series that follows a bell curve. The normal-range product has many potential applications. DA - 2006/6// PY - 2006/6// DO - 10.1175/BAMS-87-6-769 VL - 87 IS - 6 SP - 769-+ SN - 1520-0477 ER - TY - JOUR TI - Bird evolution AU - Clarke, J. AU - Middleton, K. T2 - Current Biology DA - 2006/// PY - 2006/// VL - 16 IS - 10 SP - R350-354 ER - TY - JOUR TI - Application of dynamic linear regression to improve the skill of ensemble-based deterministic ozone forecasts AU - Pagowski, M AU - Grell, GA AU - Devenyi, D AU - Peckham, SE AU - McKeen, SA AU - Gong, W AU - Delle Monache, L AU - McHenry, JN AU - McQueen, J AU - Lee, P T2 - ATMOSPHERIC ENVIRONMENT AB - Forecasts from seven air quality models and surface ozone data collected over the eastern USA and southern Canada during July and August 2004 provide a unique opportunity to assess benefits of ensemble-based ozone forecasting and devise methods to improve ozone forecasts. In this investigation, past forecasts from the ensemble of models and hourly surface ozone measurements at over 350 sites are used to issue deterministic 24-h forecasts using a method based on dynamic linear regression. Forecasts of hourly ozone concentrations as well as maximum daily 8-h and 1-h averaged concentrations are considered. It is shown that the forecasts issued with the application of this method have reduced bias and root mean square error and better overall performance scores than any of the ensemble members and the ensemble average. Performance of the method is similar to another method based on linear regression described previously by Pagowski et al., but unlike the latter, the current method does not require measurements from multiple monitors since it operates on individual time series. Improvement in the forecasts can be easily implemented and requires minimal computational cost. DA - 2006/6// PY - 2006/6// DO - 10.1016/j.atmosenv.2006.02.006 VL - 40 IS - 18 SP - 3240-3250 SN - 1352-2310 KW - photochemical air quality KW - modeling KW - ozone KW - ensemble forecast ER - TY - JOUR TI - A numerical study on hurricane-induced storm surge and inundation in Charleston Harbor, South Carolina AU - Peng, Machuan AU - Xie, Lian AU - Pietrafesa, Leonard J. T2 - JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS AB - A storm surge and inundation model is configured in Charleston Harbor and its adjacent coastal region to study the harbor's response to hurricanes. The hydrodynamic component of the modeling system is based on the Princeton Ocean Model, and a scheme with multiple inundation speed options is imbedded in the model for the inundation calculation. Historic observations (Hurricane Hugo and its related storm surge and inundation) in the Charleston Harbor region indicate that among three possible inundation speeds in the model, taking C t ( gd ) 1/2 ( C t is a terrain‐related parameter) as the inundation speed is the best choice. Choosing a different inundation speed in the model has effects not only on inundation area but also on storm surge height. A nesting technique is necessary for the model system to capture the mesoscale feature of a hurricane and meanwhile to maintain a higher horizontal resolution in the harbor region, where details of the storm surge and inundation are required. Hurricane‐induced storm surge and inundation are very sensitive to storm tracks. Twelve hurricanes with different tracks are simulated to investigate how Charleston Harbor might respond to tracks that are parallel or perpendicular to the coastline or landfall at Charleston at different angles. Experiments show that large differences of storm surge and inundation may have occurred if Hurricane Hugo had approached Charleston Harbor with a slightly different angle. A hurricane's central pressure, radius of maximum wind, and translation speed have their own complicated effects on surge and inundation when the hurricane approaches the coast on different tracks. Systematic experiments are performed in order to illustrate how each of such factors, or a combination of them, may affect the storm surge height and inundation area in the Charleston Harbor region. Finally, suggestions are given on how this numerical model system may be used for hurricane‐induced storm surge and inundation forecasting. DA - 2006/8/15/ PY - 2006/8/15/ DO - 10.1029/2004jc002755 VL - 111 IS - C8 SP - SN - 2169-9291 ER - TY - JOUR TI - A nonhydrostatic primitive-equation model for studying small-scale processes: An object-oriented approach AU - Shaw, Ping-Tung AU - Chao, Shenn-Yu T2 - CONTINENTAL SHELF RESEARCH AB - A nonhydrostatic model for simulating small-scale processes in the ocean is described. The model is developed using the object-oriented approach. The system is modeled as a set of cooperating objects to manage both the behavioral and information complexity associated with modeling oceanic processes. Objects are storage variables that are created based on classes. A class defines the variables and routines that are members of all objects of that class. The program accesses data stored in these objects using the defined interfaces. Because both data and function are accessed through objects, the model is better organized than one written in a procedural language. The program is easier to understand, debug, maintain, and evolve. Abstraction of the data in the nonhydrostatic model is implemented in both C++ and Matlab. Three examples obtained from the Matlab version of the code illustrate the capabilities of the model in cases where nonhydrostatic effects are important. The model successfully simulates nonhydrostatic atmospheric lee waves, internal waves at a discharge plume, and internal solitary waves generated by tidal flow over a sill. These examples show that the model is capable of studying strongly nonlinear, nonhydrostatic flow processes. DA - 2006/8// PY - 2006/8// DO - 10.1016/j.csr.2006.01.018 VL - 26 IS - 12-13 SP - 1416-1432 SN - 1873-6955 KW - nonhydrostatic modeling KW - small-scale processes KW - nonlinear internal waves KW - object-oriented programming ER - TY - JOUR TI - Tropical cyclone induced asymmetry of sea level surge and fall and its presentation in a storm surge model with parametric wind fields AU - Peng, Machuan AU - Xie, Lian AU - Pietrafesa, Leonard J. T2 - OCEAN MODELLING AB - The asymmetry of tropical cyclone induced maximum coastal sea level rise (positive surge) and fall (negative surge) is studied using a three-dimensional storm surge model. It is found that the negative surge induced by offshore winds is more sensitive to wind speed and direction changes than the positive surge by onshore winds. As a result, negative surge is inherently more difficult to forecast than positive surge since there is uncertainty in tropical storm wind forecasts. The asymmetry of negative and positive surge under parametric wind forcing is more apparent in shallow water regions. For tropical cyclones with fixed central pressure, the surge asymmetry increases with decreasing storm translation speed. For those with the same translation speed, a weaker tropical cyclone is expected to gain a higher AI (asymmetry index) value though its induced maximum surge and fall are smaller. With fixed RMW (radius of maximum wind), the relationship between central pressure and AI is heterogeneous and depends on the value of RMW. Tropical cyclone’s wind inflow angle can also affect surge asymmetry. A set of idealized cases as well as two historic tropical cyclones are used to illustrate the surge asymmetry. DA - 2006/// PY - 2006/// DO - 10.1016/j.ocemod.2006.03.004 VL - 14 IS - 1-2 SP - 81-101 SN - 1463-5011 KW - asymmetry KW - storm surge KW - tropical cyclone KW - parametric wind ER - TY - JOUR TI - Reflection and diffraction of internal solitary waves by a circular island AU - Chao, Shenn-Yu AU - Shaw, Ping-Tung AU - Hsu, Ming-Kuang AU - Yang, Ying-Jang T2 - JOURNAL OF OCEANOGRAPHY DA - 2006/12// PY - 2006/12// DO - 10.1007/s10872-006-0100-4 VL - 62 IS - 6 SP - 811-823 SN - 0916-8370 KW - internal solitary waves KW - wave impingement on island KW - nonhydrostatic model ER - TY - JOUR TI - Observed radar reflectivity in convectively coupled Kelvin and mixed Rossby-gravity waves AU - Swann, A AU - Sobel, AH AU - Yuter, SE AU - Kiladis, GN T2 - GEOPHYSICAL RESEARCH LETTERS AB - Propagating disturbances in the tropical atmosphere exhibiting characteristics of linear equatorial waves have been shown to be “coupled” to convection. In some cases, a rain event at a specific location can be associated with a particular wave of sufficiently large amplitude. Rain events spanning three years at Kwajalein Atoll, Republic of the Marshall Islands, 8.72°N 167.73°E, are classified by associated wave type (i.e. Kelvin or mixed Rossby‐gravity (MRG)) using space‐time spectral‐filtered outgoing longwave radiation (OLR). Contoured frequency by altitude diagrams (CFADs) of radar for the classified dates were compared between the two groups. The Kelvin wave accumulated CFAD has a distribution shifted to lower reflectivities compared to MRG suggesting that Kelvin storms likely contain a larger fraction of stratiform to convective area compared to MRG storms. DA - 2006/5/20/ PY - 2006/5/20/ DO - 10.1029/2006gl025979 VL - 33 IS - 10 SP - SN - 0094-8276 ER - TY - JOUR TI - Observations of precipitation size and fall speed characteristics within coexisting rain and wet snow AU - Yuter, Sandra E. AU - Kingsmill, David E. AU - Nance, Louisa B. AU - Loeffler-Mang, Martin T2 - JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY AB - Abstract Ground-based measurements of particle size and fall speed distributions using a Particle Size and Velocity (PARSIVEL) disdrometer are compared among samples obtained in mixed precipitation (rain and wet snow) and rain in the Oregon Cascade Mountains and in dry snow in the Rocky Mountains of Colorado. Coexisting rain and snow particles are distinguished using a classification method based on their size and fall speed properties. The bimodal distribution of the particles’ joint fall speed–size characteristics at air temperatures from 0.5° to 0°C suggests that wet-snow particles quickly make a transition to rain once melting has progressed sufficiently. As air temperatures increase to 1.5°C, the reduction in the number of very large aggregates with a diameter &gt; 10 mm coincides with the appearance of rain particles larger than 6 mm. In this setting, very large raindrops appear to be the result of aggregrates melting with minimal breakup rather than formation by coalescence. In contrast to dry snow and rain, the fall speed for wet snow has a much weaker correlation between increasing size and increasing fall speed. Wet snow has a larger standard deviation of fall speed (120%–230% relative to dry snow) for a given particle size. The average fall speed for observed wet-snow particles with a diameter ≥ 2.4 mm is 2 m s−1 with a standard deviation of 0.8 m s−1. The large standard deviation is likely related to the coexistence of particles of similar physical size with different percentages of melting. These results suggest that different particle sizes are not required for aggregation since wet-snow particles of the same size can have different fall speeds. Given the large standard deviation of fall speeds in wet snow, the collision efficiency for wet snow is likely larger than that of dry snow. For particle sizes between 1 and 10 mm in diameter within mixed precipitation, rain constituted 1% of the particles by volume within the isothermal layer at 0°C and 4% of the particles by volume for the region just below the isothermal layer where air temperatures rise from 0° to 0.5°C. As air temperatures increased above 0.5°C, the relative proportions of rain versus snow particles shift dramatically and raindrops become dominant. The value of 0.5°C for the sharp transition in volume fraction from snow to rain is slightly lower than the range from 1.1° to 1.7°C often used in hydrological models. DA - 2006/10// PY - 2006/10// DO - 10.1175/JAM2406.1 VL - 45 IS - 10 SP - 1450-1464 SN - 1558-8424 ER - TY - JOUR TI - Observational diagnosis and model forecast evaluation of unforecasted incipient precipitation during the 24-25 January 2000 East Coast cyclone AU - Brennan, Michael J. AU - Lackmann, Gary M. T2 - MONTHLY WEATHER REVIEW AB - Abstract Previous research has shown that a lower-tropospheric diabatically generated potential vorticity (PV) maximum associated with an area of incipient precipitation (IP) was critical to the moisture transport north of the PV maximum into the Carolinas and Virginia during the 24–25 January 2000 East Coast cyclone. This feature was almost entirely absent in short-term (e.g., 6–12 h) forecasts from the 0000 UTC 24 January 2000 operational runs of the National Centers for Environmental Prediction (NCEP) North American Mesoscale (NAM, formerly Eta) and Global Forecast System (GFS, formerly AVN) models, even though it occurred over land within and downstream of a region of relatively high data density. Observations and model analyses are used to document the forcing for ascent, moisture, and instability (elevated gravitational and/or symmetric) associated with the IP, and the evolution of the IP formation is documented with radar and satellite imagery with the goal of understanding the fundamental nature of this precipitation feature and the models’ inability to predict it. Results show that the IP formed along a zone of lower-tropospheric frontogenesis in a region of strong synoptic-scale forcing for ascent downstream of an approaching upper trough and jet streak. The atmosphere above the frontal inversion was characterized by a mixture of gravitational conditional instability and conditional symmetric instability over a deep layer, and this instability was likely released when air parcels reached saturation as they ascended the frontal surface. The presence of elevated convection is suggested by numerous surface reports of thunder and the cellular nature of radar echoes in the region. Short-term forecasts from the Eta and AVN models failed to capture the magnitude of the frontogenesis, upper forcing, or elevated instability in the region of IP formation. These findings suggest that errors in the initial condition analyses, particularly in the water vapor field, in conjunction with the inability of model physics schemes to generate the precipitation feature, likely played a role in the operational forecast errors related to inland quantitative precipitation forecasts (QPFs) later in the event. A subsequent study will serve to clarify the role of initial conditions and model physics in the representation of the IP by NWP models. DA - 2006/8// PY - 2006/8// DO - 10.1175/MWR3184.1 VL - 134 IS - 8 SP - 2033-2054 SN - 1520-0493 ER - TY - JOUR TI - Measurement and estimation of ammonia emissions from lagoon-atmosphere interface using a coupled mass transfer and chemical reactions model, and an equilibrium model AU - Bajwa, Kanwardeep S. AU - Aneja, Viney P. AU - Arya, S. Pal T2 - ATMOSPHERIC ENVIRONMENT AB - Ammonia has recently gained importance for its increasing atmospheric concentrations and its role in the formation of aerosols. The anaerobic lagoon and spray method, commonly used for waste storage and disposal in confined animal feeding operations (CAFO), is a significant source of ammonia emissions. An accurate emission model for ammonia from aqueous surfaces can help in the development of emission factors. Data collected from field measurements made at hog waste lagoons in south eastern North Carolina, using the flow through dynamic chamber technique, were used to evaluate the Coupled mass transfer and Chemical reactions model and Equilibrium model developed by Aneja et al. [2001a. Measurement and modeling of ammonia emissions at waste treatment lagoon-Atmospheric Interface. Water, Air and Soil pollution: Focus 1, 177–188]. Sensitivity analysis shows that ammonia flux increases exponentially with lagoon temperature and pH, but a linear increase was observed with an increase in total ammoniacal nitrogen (TAN). Ammonia flux also shows a nonlinear increase with increasing wind speed. Observed ammonia fluxes were generally lower in the cold season than in the warm season when lagoon temperatures are higher. About 41% of the equilibrium model predictions and 43% of the Coupled model predictions are found to be within a factor of two of the observed fluxes. Several model performance statistics were used to evaluate the performance of the two models against the observed flux data. These indicate that the simpler Equilibrium model does as well as the Coupled model. The possible effects of the “artificial” environment within the chamber, which is different from that in the ambient atmospheric conditions above the open lagoon surface, on the measured fluxes are also recognized. DA - 2006/// PY - 2006/// DO - 10.1016/j.atmosenv.2005.12.076 VL - 40 IS - SUPPL. 2 SP - S275-S286 SN - 1352-2310 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33748805536&partnerID=MN8TOARS KW - ammonia flux KW - coupled model KW - equilibrium model KW - mass transfer KW - two-film transfer model ER - TY - JOUR TI - Interannual and seasonal variation of the Huanghe (Yellow River) water discharge over the past 50 years: Connections to impacts from ENSO events and dams AU - Wang, Houjie AU - Yang, Zuosheng AU - Saito, Yoshiki AU - Liu, J. Paul AU - Sun, Xiaoxia T2 - Global and Planetary Change AB - The Huanghe, the second largest river in China, is now under great pressure as a water resource. Using datasets of river water discharge, water consumption and regional precipitation for the past 50 years, we elucidate some connections between decreasing water discharges, global El Niño/Southern Oscillation (ENSO) events and anthropogenic impacts in the drainage basin. Global ENSO events, which directly affected the regional precipitation in the river basin, resulted in approximately 51% decrease in river water discharge to the sea. The degree of anthropogenic impacts on river water discharge is now as great as that of natural influences, accelerating the water losses in the hydrological cycle. The large dams and reservoirs regulated the water discharge and reduced the peak flows by storing the water in the flood season and releasing it in the dry season as needed for agricultural irrigation. Thus, as a result, large dams and reservoirs have shifted the seasonal distribution patterns of water discharge and water consumption and finally resulted in rapidly increasing water consumption. Meanwhile, the annual distribution pattern of water consumption also changed under the regulation of dams and reservoirs, indicating that the people living in the river basin consume the water more and more to suit actual agricultural schedule rather than depending upon natural pattern of annual precipitation. The combination of the increasing water consumption facilitated by the dams and reservoirs and the decreasing precipitation closely associated with the global ENSO events over the past half century has resulted in water scarcity in this world-famous river, as well as in a number of subsequent serious results for the river, delta and coastal ocean. DA - 2006/4// PY - 2006/4// DO - 10.1016/j.gloplacha.2006.01.005 VL - 50 IS - 3-4 SP - 212-225 J2 - Global and Planetary Change LA - en OP - SN - 0921-8181 UR - http://dx.doi.org/10.1016/j.gloplacha.2006.01.005 DB - Crossref KW - Huanghe (Yellow River) KW - water discharge KW - ENSO events KW - dams impacts ER - TY - JOUR TI - Integrated processes analysis and systematic meteorological classification of ozone episodes in Hong Kong AU - Huang, J. P. AU - Fung, J. C. H. AU - Lau, A. K. H. T2 - Journal of Geophysical Research. Atmospheres DA - 2006/// PY - 2006/// VL - 111 IS - D20 ER - TY - JOUR TI - Human and natural predators combine to alter behavior and reduce survival of Caribbean spiny lobster AU - Parsons, DM AU - Eggleston, DB T2 - JOURNAL OF EXPERIMENTAL MARINE BIOLOGY AND ECOLOGY AB - Fishing disturbance can have indirect negative effects on animal behavior and survival, but receives little attention compared to measures of direct fisheries extraction. We quantified changes in the density of Caribbean spiny lobster Panulirus argus when exposed to experimental human disturbance and injury typical of sport-diver harvest attempts in the field. A complementary study in a large seawater arena quantified lobster sheltering behavior and survival when exposed to the single and combined effects of human disturbance and triggerfish Balistes capriscus predators. Human disturbance and injury of lobsters in the field caused lobsters to emigrate from shelters that had been typically occupied over successive days. Similarly, both the presence of triggerfish predators and human disturbance promoted decreased lobster shelter fidelity to individual shelters in the arena. Overall shelter use and gregariousness increased in the presence of natural triggerfish predators but not as a function of human disturbance. Decreased shelter use and gregariousness by lobsters when exposed to human disturbance may have contributed to their decreased survival when exposed simultaneously to triggerfish. These results highlight how human disturbance and injury of lobsters can alter their behavior and reduce subsequent survival in the presence of their natural predators, and illustrate the need to incorporate the negative effects of sport-divers into models that estimate population demographic rates. DA - 2006/7/11/ PY - 2006/7/11/ DO - 10.1016/j.jembe.2006.01.020 VL - 334 IS - 2 SP - 196-205 SN - 0022-0981 KW - behavioral mechanisms KW - indirect effects KW - Panulirus argus KW - sport divers KW - sub-lethal human disturbance KW - unobserved mortality ER - TY - JOUR TI - Effect of stable layer formation over the Po valley on the development of convection during MAP IOP-8 AU - Reeves, Heather Dawn AU - Lin, Yuh-Lang T2 - JOURNAL OF THE ATMOSPHERIC SCIENCES AB - Abstract During intensive observation period (IOP)-8 of the Mesoscale Alpine Program, there was a stable layer of air in the lowest levels of the Po Valley and just upstream of the Apennines. In this study, the effects of the stable layer on the formation of convection in the southern Alpine region were investigated through a series of two-dimensional, idealized experiments. The goals of this study were twofold: 1) to determine if stable layer strength affected the placement of convection and 2) to test the notion that the stable layer during IOP-8 behaved as an effective mountain. To accomplish the first objective, three simulations were compared in which the strength of the inversion and low-level cooling in the Po Valley and upstream of the Apennines was varied. The results of these simulations show that the stronger the inversion and low-level cooling, the farther south the convection was positioned. Additionally, it was found that convection developed as a result of the formation of a broad region of moist instability over the stable layer. Cellular convection developed in this region of moist instability. The second objective was tested through a simulation where the cold pool was replaced by terrain (MMTN). As in the reference (or STB10) simulation, the upslope of the terrain in the MMTN simulation was characterized by a wide zone of moist instability. However, wave structures to the lee of the Apennines were markedly different in the STB10 and MMTN simulations. This led to different convective and precipitation patterns, with the MMTN simulation exhibiting heavier convection over the Po Valley while the heaviest convection in STB10 was upstream of the Apennines. These results suggest that, at best, the stable layer in the STB10 simulation can only be roughly approximated by terrain. DA - 2006/10// PY - 2006/10// DO - 10.1175/JAS3759.1 VL - 63 IS - 10 SP - 2567-2584 SN - 1520-0469 ER - TY - JOUR TI - Effect of determining initial conditions by four-dimensional variational data assimilation on storm surge forecasting AU - Peng, S. -Q. AU - Xie, L. T2 - OCEAN MODELLING AB - A tangent linear model and an adjoint model of the three-dimensional, time-dependent, nonlinear Princeton Ocean Model (POM) are developed to construct a four-dimensional variational data assimilation (4D-Var) algorithm for coastal ocean prediction. To verify and evaluate the performance of this 4D-Var method, a suite of numerical experiments are conducted for a storm surge case using model-generated “pseudo-observations”. The pseudo-observations are generated by a nested-grid high-resolution numerical model which is coupled to an inundation/drying scheme that is not included in the original POM. The 4D-Var algorithm based on POM is tested thoroughly for both code accuracy and the potential application in storm surge forecasting. The assimilation cycles lead to effective convergence between the forecasts and the “observations”. Assimilating water level alone or together with surface currents both lead to significant improvements in storm surge forecasts within and several hours beyond the data assimilation window. It is worth noting that, assimilating water level alone produces improvements in storm surge forecasts that are comparable to those by assimilating both water level and surface currents, suggesting that optimizations of water level and surface currents are linked through the 4D-Var assimilation cycles. However, it is also worth noting that, the benefit resulting from the reduction of initial error in water level and/or surface currents through data assimilation decreases rapidly in time outside the assimilation window. This suggests that determining initial conditions of water level and/or surface currents via data assimilation is only effective within and a few hours beyond the assimilation window for storm surge forecasting. Thus, alternative data assimilation approaches are needed to improve the accuracy and lead time in operational storm surge forecasting. DA - 2006/// PY - 2006/// DO - 10.1016/j.ocemod.2006.03.005 VL - 14 IS - 1-2 SP - 1-18 SN - 1463-5011 KW - data assimilation KW - storm surge KW - adjoint method KW - ocean prediction KW - numerical modeling ER - TY - JOUR TI - Currents, landscape structure, and recruitment success along a passive-active dispersal gradient AU - Drew, C. Ashton AU - Eggleston, David B. T2 - LANDSCAPE ECOLOGY DA - 2006/8// PY - 2006/8// DO - 10.1007/s10980-005-5568-6 VL - 21 IS - 6 SP - 917-931 SN - 1572-9761 KW - cellular model KW - dispersal strategy KW - habitat shifts KW - hydrodynamic currents KW - recruitment success ER - TY - JOUR TI - Coherence between solar activity and the East Asian winter monsoon variability in the past 8000 years from Yangtze River-derived mud in the East China Sea AU - Xiao, S. B. AU - Li, A. C. AU - Liu, J. P. AU - Chen, M. H. AU - Xie, Q. AU - Jiang, F. Q. AU - Li, T. G. AU - Xiang, R. AU - Chen, Z. T2 - Palaeogeography, Palaeoclimatology, Palaeoecology DA - 2006/// PY - 2006/// VL - 237 IS - 4-Feb SP - 293-304 ER - TY - JOUR TI - Characterizing the severe turbulence environments associated with commercial aviation accidents. A real-time turbulence model (RTTM) designed for the operational prediction of hazardous aviation turbulence environments AU - Kaplan, M. L. AU - Charney, J. J. AU - Waight, K. T., III AU - Lux, K. M. AU - Cetola, J. D. AU - Huffman, A. W. AU - Riordan, A. J. AU - Slusser, S. D. AU - Kiefer, M. T. AU - Suffern, P. S. AU - Lin, Y. -L. T2 - METEOROLOGY AND ATMOSPHERIC PHYSICS AB - In this paper, we will focus on the real-time prediction of environments that are predisposed to producing moderate-severe (hazardous) aviation turbulence. We will describe the numerical model and its postprocessing system that is designed for said prediction of environments predisposed to severe aviation turbulence as well as presenting numerous examples of its utility. The purpose of this paper is to demonstrate that simple hydrostatic precursor circulations organize regions of preferred wave breaking and turbulence at the nonhydrostatic scales of motion. This will be demonstrated with a hydrostatic numerical modeling system, which can be run in real time on a very inexpensive university computer workstation employing simple forecast indices. The forecast system is designed to efficiently support forecasters who are directing research aircraft to measure the environment immediately surrounding turbulence. The numerical model is MASS version 5.13, which is integrated over three different grid matrices in real-time on a university workstation in support of NASA-Langley’s B-757 turbulence research flight missions. The model horizontal resolutions are 60, 30, and 15 km and the grids are centered over the region of operational NASA-Langley B-757 turbulence flight missions. The postprocessing system includes several turbulence-related products including four turbulence forecasting indices, winds, streamlines, turbulence kinetic energy, and Richardson numbers. Additionally there are convective products including precipitation, cloud height, cloud mass fluxes, lifted index, and K-index. Furthermore, soundings, sounding parameters, and Froude number plots are also provided. The horizontal cross section plot products are provided from 16,000–46,000 feet in 2,000 feet intervals. Products are available every three hours at the 60 and 30 km grid interval and every 1.5 hours at the 15 km grid interval. The model is initialized from the NWS ETA analyses and integrated two times a day. DA - 2006/11// PY - 2006/11// DO - 10.1007/s00703-005-0181-4 VL - 94 IS - 1-4 SP - 235-270 SN - 0177-7971 ER - TY - JOUR TI - Analysis of mean climate conditions in Senegal (1971-98) AU - Fall, S. AU - Niyogi, D. AU - Semazzi, F. H. M. T2 - Earth Interactions AB - Abstract This paper presents a GIS-based analysis of climate variability over Senegal, West Africa. It responds to the need for developing a climate atlas that uses local observations instead of gridded global analyses. Monthly readings of observed rainfall (20 stations) and mean temperature (12 stations) were compiled, digitized, and quality assured for a period from 1971 to 1998. The monthly, seasonal, and annual temperature and precipitation distributions were mapped and analyzed using ArcGIS Spatial Analyst. A north–south gradient in rainfall and an east–west gradient in temperature variations were observed. June exhibits the greatest variability for both quantity of rainfall and number of rainy days, especially in the western and northern parts of the country. Trends in precipitation and temperature were studied using a linear regression analysis and interpolation maps. Air temperature showed a positive and significant warming trend throughout the country, except in the southeast. A significant correlation is found between the temperature index for Senegal and the Pacific sea surface temperatures during the January–April period, especially in the El Niño zone. In contrast to earlier regional-scale studies, precipitation does not show a negative trend and has remained largely unchanged, with a few locations showing a positive trend, particularly in the northeastern and southwestern regions. This study reveals a need for more localized climate analyses of the West Africa region because local climate variations are not always captured by large-scale analysis, and such variations can alter conclusions related to regional climate change. DA - 2006/// PY - 2006/// DO - 10.1175/ei158.1 VL - 10 ER - TY - JOUR TI - An extended procedure for implementing the relative operating characteristic graphical method AU - Semazzi, Fredrick H. M. AU - Mera, Roberto J. T2 - JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY AB - Abstract The functional relationship between the relative operating characteristic (ROC) and the economic value (EV) graphical methods have been exploited to develop a hybrid procedure called the extended ROC (EROC) method. The EROC retains the appealing simplicity of the traditional ROC method and the ability of the EV method to provide evaluation of the performance of an ensemble climate prediction system (EPS) for a hypothetical end user defined by the cost–loss ratio (μ = C/L). An inequality defining the lower and upper theoretical bounds of μ has been derived. Outside these limits, the EPS yields no added benefits for end user μ relative to the use of climatological persistence as an alternative prediction system. In the traditional ROC graphical method, the ROC skill (ROCS) is often expressed in terms of the area between the ROC graph and the diagonal baseline passing through the origin with slope m = 1. Thus, ROCS = 2A − 1, where A is the area under the ROC graph. In the proposed EROC approach, a more general procedure is recommended based on the construction of user-specific baselines that do not necessarily pass through the origin and, in general, have slope m ≠ 1. The skill of a particular EPS computed from the EROC method is proportional to the corresponding estimated value based on the EV graphical method. Therefore, the EROC geometry conveys the same basic information as the EV method. The Semazzi–Mera skill score (SMSS) is proposed as a convenient and compact way of expressing the combined verification based on the ROC and EV methods. The ROCS estimate is a special case of the SMSS. The near-horizontal trail-like geometry sometimes exhibited by EV graphs is also examined. It is shown to occur when either the hit-rate or false-alarm term dominates in the formula for EV, unlike the more typical situation in which both terms are comparable in magnitude. DA - 2006/9// PY - 2006/9// DO - 10.1175/JAM2397.1 VL - 45 IS - 9 SP - 1215-1223 SN - 1558-8432 ER - TY - JOUR TI - An examination of the CMAQ simulations of the wet deposition of ammonium from a Bayesian perspective AU - Davis, Jerry M. AU - Swall, Jenise L. T2 - ATMOSPHERIC ENVIRONMENT AB - The ability of the US Environmental Protection Agency's Community Multi-scale Air Quality (CMAQ) model to simulate the wet deposition of ammonium during 8-week winter and summer periods in 2001 is evaluated using observations from the National Acid Deposition Program (NADP) monitoring sites. The objective of this study is to ascertain the effects of precipitation simulations and emissions on CMAQ simulations of deposition. In both seasons, CMAQ tends to underpredict the deposition amounts. Based on the co-located measurements of ammonium wet deposition and precipitation at the NADP sites and on estimated precipitation amounts for each grid cell, Bayesian statistical methods are used to estimate ammonium wet deposition over all grid cells in the study region. To assess the effect of precipitation on the CMAQ simulations, our statistical method is run twice for each time period, using the simulated precipitation information provided to CMAQ and precipitation estimates based on data collected by the cooperative observer network. During the winter period when stratiform-type precipitation dominates, precipitation amounts do not seem to be a major factor in CMAQ's ability to simulate the wet deposition of ammonium. However, during the summer period when precipitation is mainly generated by convective processes, small portions of the region are identified in which problems with precipitation simulations may be adversely affecting CMAQ's estimates. DA - 2006/8// PY - 2006/8// DO - 10.1016/j.atmosenv.2006.04.007 VL - 40 IS - 24 SP - 4562-4573 SN - 1873-2844 KW - ammonium wet deposition KW - model evaluation KW - Bayesian statistical methods KW - spatial correlation KW - community multi-scale air quality (CMAQ) model KW - national acid deposition program (NADP) KW - ammonia emissions ER - TY - JOUR TI - Simulation of convective initiation during IHOP_2002 using the flux-adjusting surface data assimilation system (FASDAS) AU - Childs, PP AU - Qureshi, AL AU - Raman, S AU - Alapaty, K AU - Ellis, R AU - Boyles, R AU - Niyogi, D T2 - MONTHLY WEATHER REVIEW AB - Abstract The Flux-Adjusting Surface Data Assimilation System (FASDAS) uses the surface observational analysis to directly assimilate surface layer temperature and water vapor mixing ratio and to indirectly assimilate soil moisture and soil temperature in numerical model predictions. Both soil moisture and soil temperature are important variables in the development of deep convection. In this study, FASDAS coupled within the fifth-generation Pennsylvania State University–NCAR Mesoscale Model (MM5) was used to study convective initiation over the International H2O Project (IHOP_2002) region, utilizing the analyzed surface observations collected during IHOP_2002. Two 72-h numerical simulations were performed. A control simulation was run that assimilated all available IHOP_2002 measurements into the standard MM5 four-dimensional data assimilation. An experimental simulation was also performed that assimilated all available IHOP_2002 measurements into the FASDAS version of the MM5, where surface observations were used for the FASDAS coupling. Results from this case study suggest that the use of FASDAS in the experimental simulation led to the generation of greater amounts of precipitation over a more widespread area as compared to the standard MM5 FDDA used in the control simulation. This improved performance is attributed to better simulation of surface heat fluxes and their gradients. DA - 2006/1// PY - 2006/1// DO - 10.1175/MWR3064.1 VL - 134 IS - 1 SP - 134-148 SN - 1520-0493 ER - TY - JOUR TI - Effect of land-atmosphere interactions on the IHOP 24-25 May 2002 convection case AU - Holt, TR AU - Niyogi, D AU - Chen, F AU - Manning, K AU - LeMone, MA AU - Qureshi, A T2 - MONTHLY WEATHER REVIEW AB - Abstract Numerical simulations are conducted using the Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) to investigate the impact of land–vegetation processes on the prediction of mesoscale convection observed on 24–25 May 2002 during the International H2O Project (IHOP_2002). The control COAMPS configuration uses the Weather Research and Forecasting (WRF) model version of the Noah land surface model (LSM) initialized using a high-resolution land surface data assimilation system (HRLDAS). Physically consistent surface fields are ensured by an 18-month spinup time for HRLDAS, and physically consistent mesoscale fields are ensured by a 2-day data assimilation spinup for COAMPS. Sensitivity simulations are performed to assess the impact of land–vegetative processes by 1) replacing the Noah LSM with a simple slab soil model (SLAB), 2) adding a photosynthesis, canopy resistance/transpiration scheme [the gas exchange/photosynthesis-based evapotranspiration model (GEM)] to the Noah LSM, and 3) replacing the HRLDAS soil moisture with the National Centers for Environmental Prediction (NCEP) 40-km Eta Data Assimilation (EDAS) operational soil fields. CONTROL, EDAS, and GEM develop convection along the dryline and frontal boundaries 2–3 h after observed, with synoptic-scale forcing determining the location and timing. SLAB convection along the boundaries is further delayed, indicating that detailed surface parameterization is necessary for a realistic model forecast. EDAS soils are generally drier and warmer than HRLDAS, resulting in more extensive development of convection along the dryline than for CONTROL. The inclusion of photosynthesis-based evapotranspiration (GEM) improves predictive skill for both air temperature and moisture. Biases in soil moisture and temperature (as well as air temperature and moisture during the prefrontal period) are larger for EDAS than HRLDAS, indicating land–vegetative processes in EDAS are forced by anomalously warmer and drier conditions than observed. Of the four simulations, the errors in SLAB predictions of these quantities are generally the largest. By adding a sophisticated transpiration model, the atmospheric model is able to better respond to the more detailed representation of soil moisture and temperature. The sensitivity of the synoptically forced convection to soil and vegetative processes including transpiration indicates that detailed representation of land surface processes should be included in weather forecasting models, particularly for severe storm forecasting where local-scale information is important. DA - 2006/1// PY - 2006/1// DO - 10.1175/MWR3057.1 VL - 134 IS - 1 SP - 113-133 SN - 0027-0644 ER - TY - JOUR TI - On completion problems for various classes of P-matrices AU - Bowers, J AU - Evers, J AU - Hogben, L AU - Shaner, S AU - Snider, K AU - Wangsness, A T2 - LINEAR ALGEBRA AND ITS APPLICATIONS AB - A P -matrix is a real square matrix having every principal minor positive, and a Fischer matrix is a P -matrix that satisfies Fischer’s inequality for all principal submatrices. In this paper, all patterns of positions for n × n matrices, n ⩽ 4, are classified as to whether or not every partial Π -matrix can be completed to a Π -matrix for Π any of the classes positive P -, nonnegative P -, or Fischer matrices. Also, all symmetric patterns for 5 × 5 matrices are classified as to completion of partial Fischer matrices, and all but two such patterns are classified as to positive P - or nonnegative P -completion. We also show that any pattern whose digraph contains a minimally chordal symmetric-Hamiltonian induced subdigraph does not have Π -completion for Π any of the classes positive P -, nonnegative P -, Fischer matrices. DA - 2006/3/1/ PY - 2006/3/1/ DO - 10.1016/j.laa.2005.10.007 VL - 413 IS - 2-3 SP - 342-354 SN - 1873-1856 KW - matrix completion KW - partial matrix KW - p-matrix KW - nonnegative p-matrix KW - positive p-matrix KW - Fischer matrix KW - weakly sign-symmetric p-matrix ER - TY - JOUR TI - The sensitivity of numerical forecasts to convective parameterization: A case study of the 17 February 2004 east coast cyclone AU - Mahoney, Kelly M. AU - Lackmann, Gary M. T2 - WEATHER AND FORECASTING AB - Abstract The sensitivity of numerical model forecasts of coastal cyclogenesis and frontogenesis to the choice of model cumulus parameterization (CP) scheme is examined for the 17 February 2004 southeastern U.S. winter weather event. This event featured a complex synoptic and mesoscale environment, as the presence of cold-air damming, a developing coastal surface cyclone, and an upper-level trough combined to present a daunting winter weather forecast scenario. The operational forecast challenge was further complicated by erratic numerical model predictions. The most poignant area of disagreement between model runs was the treatment of a coastal cyclone and an associated coastal front, features that would affect the location and timing of precipitation and influence the precipitation type. At the time of the event, it was hypothesized that the Betts–Miller–Janjić (BMJ) CP scheme was dictating the location and intensity of the initial coastal cyclone center in operational Eta Model forecasts. For this reason, forecasts for this case were rerun with the workstation Eta Model using the Kain–Fritsch (KF) CP scheme to further examine the sensitivity to this parameterization choice. Results confirm that the model CP scheme played a major role in the forecast for this case, affecting the quantitative precipitation forecast as well as the strength, location, and structure of coastal cyclogenesis and coastal frontogenesis. The Eta Model forecast using the KF CP scheme produced a relatively uniform distribution of convective precipitation oriented along the axis of an inverted trough and strong coastal front. In contrast, the BMJ forecasts resulted in a weaker coastal front and the development of multiple distinct closed cyclonic circulations in association with more localized convective precipitation centers. An additional BMJ forecast in which the shallow mixing component of the scheme was disabled bore a closer semblance to the KF forecasts relative to the original BMJ forecast. Suggestions are provided to facilitate the identification of CP-driven cyclones using standard operational model output parameters. DA - 2006/8// PY - 2006/8// DO - 10.1175/WAF937.1 VL - 21 IS - 4 SP - 465-488 SN - 1520-0434 ER - TY - JOUR TI - Observations and numerical simulation of the sea and land breeze circulations along the west coast of India AU - Simpson, M. D. AU - Raman, S. T2 - Indian Journal of Marine Sciences DA - 2006/// PY - 2006/// VL - 35 IS - 2 SP - 139-152 ER - TY - JOUR TI - Environmental influences on tropical cyclone structure and intensity: A review of past and present literature AU - Rhome, J. R. AU - Raman, S. T2 - Indian Journal of Marine Sciences DA - 2006/// PY - 2006/// VL - 35 IS - 2 SP - 61-74 ER - TY - JOUR TI - A mathematical model for forecasting tropical cyclone tracks AU - Xu, XD AU - Xie, LA AU - Zhang, XJ AU - Yao, WQ T2 - NONLINEAR ANALYSIS-REAL WORLD APPLICATIONS AB - The kinematics and dynamics of tropical cyclone (TC) tracks are studied by using a mathematical model of track curvature. The results indicate that the curvature of storm track is determined by a set of ‘controlling parameters’ related to the storm characteristics and the ambient atmospheric circulation. These controlling parameters include the speed of storm motion, storm intensity and size, the Coriolis parameter, ambient atmospheric pressure field, and surface friction. In northern hemisphere, a northward moving TC tends to gain anti-cyclonic curvature and deflect to the right. A westward or northwestward moving TC will also deflect to the right when it slows down. A westward-moving TC along the southern edge of the sub-tropical high tends to deflect to the right as it moves toward the “turning point” of the large scale flow field (i.e. the southwest corner of the subtropical high). An eastward-moving TC along the northern edge of the sub-tropical high tends to deflect leftward toward the low-pressure side of the steering flow. A TC located in front of a westerly trough will gain cyclonic curvature. Thus, a re-curving TC after passing its western most location will tend to deflect to the low-pressure side. Finally, TC intensity and size change can also affect the TC movement. For example, a westward moving, deepening or enlarging TC tends to move anti-cyclonically. DA - 2006/4// PY - 2006/4// DO - 10.1016/j.nonrwa.2004.04.004 VL - 7 IS - 2 SP - 211-224 SN - 1468-1218 KW - motion curvature KW - mathematical model KW - tropical cyclone (TC) KW - storm track ER - TY - JOUR TI - Interbasin groundwater flow and groundwater interaction with surface water in a lowland rainforest, Costa Rica: A review AU - Genereux, DP AU - Jordan, M T2 - JOURNAL OF HYDROLOGY AB - Abstract This paper reviews work related to interbasin groundwater flow (naturally occurring groundwater flow beneath watershed topographic divides) into lowland rainforest watersheds at La Selva Biological Station in Costa Rica. Chemical mixing calculations (based on dissolved chloride) have shown that up to half the water in some streams and up to 84% of the water in some riparian seeps and wells is due to high-solute interbasin groundwater flow (IGF). The contribution is even greater for major ions; IGF accounts for well over 90% of the major ions at these sites. Proportions are highly variable both among watersheds and with elevation within the same watershed (there is greater influence of IGF at lower elevations). The large proportion of IGF found in water in some riparian wetlands suggests that IGF is largely responsible for maintaining these wetlands. δ 18 O data support the conclusions from the major ion data. Annual water and major ion budgets for two adjacent watersheds, one affected by IGF and the other not, showed that IGF accounted for two-thirds of the water input and 92–99% of the major ion input (depending on the major ion in question) to the former watershed. The large (in some cases, dominating) influence of IGF on watershed surface water quantity and quality has important implications for stream ecology and watershed management in this lowland rainforest. Because of its high phosphorus content, IGF increases a variety of ecological variables (algal growth rates, leaf decay rate, fungal biomass, invertebrate biomass, microbial respiration rates on leaves) in streams at La Selva. The significant rates of IGF at La Selva also suggest the importance of regional (as opposed to small-scale local) water resource planning that links lowland watersheds with regional groundwater. IGF is a relatively unexplored and potentially critical factor in the conservation of lowland rainforest. DA - 2006/4/15/ PY - 2006/4/15/ DO - 10.1016/j.jhydrol.2005.07.023 VL - 320 IS - 3-4 SP - 385-399 SN - 1879-2707 KW - groundwater KW - watershed KW - tracer KW - rainforest KW - streamflow KW - wetland KW - tropical ER - TY - JOUR TI - A real-time hurricane surface wind forecasting model: Formulation and verification AU - Xie, L AU - Bao, SW AU - Pietrafesa, LJ AU - Foley, K AU - Fuentes, M T2 - MONTHLY WEATHER REVIEW AB - Abstract A real-time hurricane wind forecast model is developed by 1) incorporating an asymmetric effect into the Holland hurricane wind model; 2) using the National Oceanic and Atmospheric Administration (NOAA)/National Hurricane Center’s (NHC) hurricane forecast guidance for prognostic modeling; and 3) assimilating the National Data Buoy Center (NDBC) real-time buoy data into the model’s initial wind field. The method is validated using all 2003 and 2004 Atlantic and Gulf of Mexico hurricanes. The results show that 6- and 12-h forecast winds using the asymmetric hurricane wind model are statistically more accurate than using a symmetric wind model. Detailed case studies were conducted for four historical hurricanes, namely, Floyd (1999), Gordon (2000), Lily (2002), and Isabel (2003). Although the asymmetric model performed generally better than the symmetric model, the improvement in hurricane wind forecasts produced by the asymmetric model varied significantly for different storms. In some cases, optimizing the symmetric model using observations available at initial time and forecast mean radius of maximum wind can produce comparable wind accuracy measured in terms of rms error of wind speed. However, in order to describe the asymmetric structure of hurricane winds, an asymmetric model is needed. DA - 2006/5// PY - 2006/5// DO - 10.1175/MWR3126.1 VL - 134 IS - 5 SP - 1355-1370 SN - 0027-0644 ER - TY - JOUR TI - Scale-dependent movements and protection of female blue crabs (Callinectes sapidus) AU - Medici, D. A. AU - Wolcott, T. G. AU - Wolcott, D. L. T2 - Canadian Journal of Fisheries and Aquatic Sciences DA - 2006/// PY - 2006/// DO - 10.1103/F05-263 VL - 63 IS - 4 SP - 858-871 ER - TY - PCOMM TI - Concern about gag rules AU - Pietrafesa, L. AB - With regard to Donald Kennedy's Editorial “The new gag rules” (17 Feb., p. [917][1]), the National Oceanic and Atmospheric Administration's (NOAA) Science Advisory Board (SAB) is deeply concerned about reports of attempts to suppress and/or distort the reporting or representation of scientific DA - 2006/// PY - 2006/// DO - 10.1126/science.312.5777.1137d SP - 1137-1138 ER - TY - JOUR TI - Superparamagnetic relaxation times for mixed anisotropy and high energy barriers with intermediate to high damping: 2. Uniaxial axis in a < 111 > direction AU - Newell, AJ T2 - GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS AB - Superparamagnetic relaxation rates are calculated for ferromagnetic particles with mixed cubic and uniaxial anisotropy. In part 1 the uniaxial axis is in a 〈001〉 crystallographic direction, while in this article it is in a 〈111〉 crystallographic direction. When K u = 0, there are six remanent states but only one relaxation rate. As K u increases, the remanent states converge on the uniaxial axis, merging with it at K u = 0.76 K ′ 1 for K ′ 1 > 0 and at K u = 0.22 ∣ K ′ 1 ∣ for K ′ 1 < 0. In between the components parallel and perpendicular to the uniaxial axis relax at different rates. The rate for the perpendicular component increases with K u . If all the remanent states have the same energy, there is a single, decreasing rate for the parallel component. However, for some values of K u and K ′ 1 there are two states with two different energies. There are then two rates, one decreasing and one increasing. For large K u the remanence is uniaxial. In this article and part 1 the relaxation rates have an exponential and a prefactor. The prefactors are calculated in the high energy barrier, intermediate‐ to high‐damping approximation. For elongated particles the prefactor is smaller than predicted by the Néel‐Brown theory for uniaxial particles. The predicted relaxation rates are the same order of magnitude as experimental estimates for maghemite and magnetite. Better agreement cannot be expected because order‐of‐magnitude uncertainties still exist in both the experimental and theoretical estimates. DA - 2006/3/29/ PY - 2006/3/29/ DO - 10.1029/2005gc001147 VL - 7 SP - SN - 1525-2027 KW - anisotropy KW - ferromagnetic KW - relaxation KW - single-domain KW - superparamagnetic KW - viscous KW - geomagnetism and paleomagnetism : paleointensity KW - geomagnetism and paleomagnetism : remagnetization KW - geomagnetism and paleomagnetism : rock and mineral magnetism ER - TY - JOUR TI - Superparamagnetic relaxation times for mixed anisotropy and high energy barriers with intermediate to high damping: 1. Uniaxial axis in a < 001 > direction AU - Newell, AJ T2 - GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS AB - The Néel‐Brown theory for superparamagnetic relaxation rates is generalized to ferromagnetic particles with mixed cubic and uniaxial anisotropy. In this article the uniaxial axis is in a 〈001〉 crystallographic direction, while in part 2 it is in a 〈111〉 direction. The calculations are for high energy barriers, so transitions between states (stable equilibria) are rare. Transition rates from an energy minimum across a saddle point are determined by the height of the energy barrier and the shape of the energy surface around these two points. To account for multiple connections between minima, a master equation is solved for the probability distribution and the effect on the magnetic moment is calculated. Some relaxation modes have no effect on the moment. There are as many as five distinct relaxation rates for the probability distribution, but at most two for the moment. One rate is for the component parallel to the uniaxial axis, while the other is for the perpendicular component. These rates are functions of the cubic anisotropy parameter K ′ 1 and the uniaxial parameter K u . The double relaxation rate can give rise to phenomena such as partial superparamagnetism and multiple blocking temperatures. DA - 2006/3/29/ PY - 2006/3/29/ DO - 10.1029/2005gc001146 VL - 7 SP - SN - 1525-2027 KW - anisotropy KW - ferromagnetic KW - relaxation KW - single-domain KW - superparamagnetic KW - viscous KW - geomagnetism and paleomagnetism : paleointensity KW - geomagnetism and paleomagnetism : remagnetization KW - geomagnetism and paleomagnetism : rock and mineral magnetism ER -