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The Maintenance Of Conservative Physical Laws Within Data Assimilation Systems, G.A. Jacobs, H.E. Ngodock
The Maintenance Of Conservative Physical Laws Within Data Assimilation Systems, G.A. Jacobs, H.E. Ngodock
Faculty Publications
In many data assimilation applications, adding an error to represent forcing to certain dynamical equations may be physically unrealistic. Four-dimensional variational methods assume either an error in the dynamical equations of motion (weak constraint) or no error (strong constraint). The weak-constraint methodology proposes the errors to represent uncertainties in either forcing of the dynamical equations or parameterizations of dynamics. Dynamical equations that represent conservation of quantities (mass, entropy, momentum, etc.) may be cast in an analytical or control volume flux form containing minimal errors. The largest errors arise in determining the fluxes through control volume surfaces. Application of forcing errors …
A Study Of Enso Prediction Using A Hybrid Coupled Model And The Adjoint Method For Data Assimilation, Eli Galanti, Eli Tziperman, Matthew Harrison, Anthony Rosati, Ziv Sirkes
A Study Of Enso Prediction Using A Hybrid Coupled Model And The Adjoint Method For Data Assimilation, Eli Galanti, Eli Tziperman, Matthew Harrison, Anthony Rosati, Ziv Sirkes
Faculty Publications
An experimental ENSO prediction system is presented, based on an ocean general circulation model (GCM) coupled to a statistical atmosphere and the adjoint method of 4D variational data assimilation. The adjoint method is used to initialize the coupled model, and predictions are performed for the period 1980-99. The coupled model is also initialized using two simpler assimilation techniques: forcing the ocean model with observed sea surface temperature and surface fluxes, and a 3D variational data assimilation (3DVAR) method, similar to that used by the National Centers for Environmental Prediction (NCEP) for operational ENSO prediction. The prediction skill of the coupled …
Prey Nutritional Quality Interacts With Chemical Defenses To Affect Consumer Feeding And Fitness, Edwin Cruz-Rivera, Mark E. Hay
Prey Nutritional Quality Interacts With Chemical Defenses To Affect Consumer Feeding And Fitness, Edwin Cruz-Rivera, Mark E. Hay
Faculty Publications
Numerous studies have assessed the individual effects of prey nutritional quality or chemical defenses on consumer feeding behavior. However, little is known about how these traits interact to affect consumer feeding and performance. We tested the separate and interactive effects of prey chemical defenses and nutritional quality on the feeding behavior and fitness of six sympatric crustacean mesograzers. Natural concentrations of diterpene alcohols (dictyols) from the brown alga Dictyota menstrualis were incorporated, or not incorporated, into lower quality and higher quality foods to create artificial diets mimicking prey of variable value and defense. Five amphipods (Ampithoe longimana, A. valida, Cymadusa …
Tidal Corrections For Topex Altimetry In The Coral Sea And Great Barrier Reef Lagoon: Comparisons With Long-Term Tide Gauge Records, D.M. Burrage, C.R. Steinberg, L.B. Mason, L. Bode
Tidal Corrections For Topex Altimetry In The Coral Sea And Great Barrier Reef Lagoon: Comparisons With Long-Term Tide Gauge Records, D.M. Burrage, C.R. Steinberg, L.B. Mason, L. Bode
Faculty Publications
[ 1] The well-known capability of TOPEX/Poseidon altimetry to map sea levels precisely in the deep oceans motivates its application to the topographically complex Coral Sea and NE Australian continental margin. We assess several global tidal models for correcting TOPEX altimetry in the Coral Sea and find CSR3.0 offers good overall performance, based on comparisons of model-predicted and tide gauge harmonic constituents. Using CSR3.0 tidal corrections, we evaluate residual Sea Surface Height (SSH) Root Mean Square (RMS) variability and residual M2 tidal alias errors. Away from large reefs and islands, CSR3.0 amplitude and phase errors for M2 are typically less …
Habitat Selection Of The Channel Darter, Percina (Cottogaster) Copelandi, A Surrogate For The Imperiled Pearl Darter, Percina Aurora, Pamela J. Schofield, Stephen T. Ross
Habitat Selection Of The Channel Darter, Percina (Cottogaster) Copelandi, A Surrogate For The Imperiled Pearl Darter, Percina Aurora, Pamela J. Schofield, Stephen T. Ross
Faculty Publications
Percina (Cottogaster) aurora is an imperiled species under consideration for listing by the U.S. Fish and Wildlife Service. To better understand habitat use of P. aurora, we studied a related and more abundant Cottogaster species, Percina copelandi, from the Ouachita River, Arkansas. We used a laboratory stream system to examine mesohabitat selection (pools versus riffles) and microhabitat selection (substratum particle size) of P. copelandi over three temperature regimes (summer, spring, and winter). Percina copelandi selected pool habitats over riffles and selected pools with coarse substrata (e.g., cobble) over fine substrata (e.g., gravel). In riffles, …
Soft-Sediment Recruitment Dynamics Of Early Blue Crab Stages In Mississippi Sound, Chet F. Rakocinski, Harriet M. Perry, Michael A. Abney, Kristen M. Larsen
Soft-Sediment Recruitment Dynamics Of Early Blue Crab Stages In Mississippi Sound, Chet F. Rakocinski, Harriet M. Perry, Michael A. Abney, Kristen M. Larsen
Faculty Publications
In order to understand the recruitment dynamics of early blue crabs, it is necessary to sample quantitatively across early stages and habitats at appropriate spatio-temporal scales. Few studies of early blue crab recruitment have considered the potential role of soft-sediment habitat or directly related megalopal supply to local densities of early stages. During a 7-wk peak recruitment period, fluctuations in early stages of blue crabs from settlement collectors were significantly cross-correlated between two sites separated by 7.5 km, showing connectivity on this large spatial scale. Moreover, numbers of megalopae from settlement collectors were directly correlated with densities of early juveniles …
Biochemical Composition Of Embryonic Blue Crabs Callinectes Sapidus Rathbun 1896 (Crustacea : Decapoda) From The Gulf Of Mexico, Janet R. Jacobs, Patricia M. Biesiot, Harriet M. Perry, Christine Trigg
Biochemical Composition Of Embryonic Blue Crabs Callinectes Sapidus Rathbun 1896 (Crustacea : Decapoda) From The Gulf Of Mexico, Janet R. Jacobs, Patricia M. Biesiot, Harriet M. Perry, Christine Trigg
Faculty Publications
Blue crab Callinectes sapidus embryos from the Mississippi Sound were sampled in spring and in late summer to determine patterns of biochemical composition and of yolk utilization during embryogenesis and to ascertain potential seasonal differences in biochemical composition. The diameter of spring embryos was similar to 6% greater than summer embryos but this significant size difference was due to increased water content, not to increased organic content. The general trend in initial biochemical composition was similar in both seasons; protein was the primary component at similar to 50% of initial dry weight followed by lipid (similar to 30%), ash (similar …
Blue Crab Larval Dispersion And Retention In The Mississippi Bight: Testing The Hypothesis, Harriet M. Perry, Donald R. Johnson, Kirsten M. Larsen, Christine Trigg, Fred Vukovich
Blue Crab Larval Dispersion And Retention In The Mississippi Bight: Testing The Hypothesis, Harriet M. Perry, Donald R. Johnson, Kirsten M. Larsen, Christine Trigg, Fred Vukovich
Faculty Publications
An hypothesis relating physical forcing to dispersion and retention of blue crab larvae was tested in the area of the Mississippi Bight. Seasonal circulation patterns derived from a 3-dimensional, primitive equation, sigma-coordinate model of the Gulf of Mexico (GOM) indicate favorable conditions for offshore dispersal of larvae and their return to nearshore waters as megalopae occur between April and October. Large basin-scale events, such as Loop Current intrusions into the GOM with spin-off eddy generation and anomalies in average wind stress may interrupt this circulation pattern and change the settlement success rate. Meteorological and hydrological factors thought to influence settlement …
The Use Of Parasites In Discriminating Stocks Of Pacific Halibut (Hippoglossus Stenolepis) In The Northeast Pacific, Reginald B. Blaylock, Leo Margolis, John C. Holmes
The Use Of Parasites In Discriminating Stocks Of Pacific Halibut (Hippoglossus Stenolepis) In The Northeast Pacific, Reginald B. Blaylock, Leo Margolis, John C. Holmes
Faculty Publications
The use of parasites as indicators of the stock structure of Pacific halibut (Hippoglossus stenolepis) in the northeast Pacific was investigated by using 328 adult (>55 cm fork length) halibut from 15 composite localities ranging from northern California to the northern Bering Sea and 96 juvenile (10-55 cm) halibut from five localities ranging from the northern Queen Charlotte Islands to the Bering Sea. Counts of eight selected parasite species (the juvenile acanthocephalans Corynosoma strumosum and C. villosum, the metacestode Nybelinia surmenicola, the digenean metacercaria Otodistomum sp., and the larval nematodes Anisakis simplex, Pseudoterranova decipiens, Contracaecum sp., and Spirurid gen. …
Effects Of Weather On Autumn Hawk Movements At Fort Morgan, Alabama, Stefan Woltmann, David Cimprich
Effects Of Weather On Autumn Hawk Movements At Fort Morgan, Alabama, Stefan Woltmann, David Cimprich
Faculty Publications
Migrating hawks were observed at Fort Morgan, Alabama during autumn 1995-1998. The three most abundant migrants were Sharp-shinned Hawk (Accipiter striatus), Broad-winged Hawk (Buteo platypterus) and American Kestrel (Falco sparverius). The three species accounted for 84% of all observations. Most individuals (> 80%) were seen heading west. Compared with days with east and south winds, days with north winds were associated with significantly higher passage rates for all species, and passage rates of Broadwinged Hawks were significantly higher on days when both a cold front and north winds occurred than on days with north winds only. …
Small-Scale Spatial And Temporal Variability In Growth And Mortality Of Fish Larvae In The Subtropical Northcentral Gulf Of Mexico: Implications For Assessing Recruitment Success, Bruce H. Comyns, Richard F. Shaw, Joanna Lyczkowski-Shultz
Small-Scale Spatial And Temporal Variability In Growth And Mortality Of Fish Larvae In The Subtropical Northcentral Gulf Of Mexico: Implications For Assessing Recruitment Success, Bruce H. Comyns, Richard F. Shaw, Joanna Lyczkowski-Shultz
Faculty Publications
Extensive plankton collections were taken during seven September cruises (1990-93) along the inner continental shelf of the northcentral Gulf of Mexico (GOM). Despite the high productivity and availability of food during these cruises, significant smallscale spatial variability was found in larval growth rates for both Atlantic bumper (Chloroscombrus chrysurus, Carangidae) and vermilion snapper (Rhomboplites aurorubens, Lutjanidae). The observed variability in larval growth rates was not correlated with changes in water temperature or associated with conspicuous hydrographic features and suggested the existence of less-recognizable regions where conditions for growth vary. Cruise estimates of mortality coefficients (Z) for larval Atlantic bumper (n=32,241 …