This research has investigated the ability to model precipitation over East Africa using the RegCM regional climate model, and the ability of a stochastic model to predict Lake Victoria lake level one season in advance. The stochastic model was built using precipitation, sea surface temperatures and temperature, and provides detail about the steps used to develop the model. Precipitation modeling was carried out using RegCM and several convective schemes were compared to determine which performed best for East Africa. Additionally the microphysical scheme SUBEX was investigated thoroughly and several tuning parameter changes were made. Finally the precipitation from RegCM was split into 9 rainfall classifications which were then studied to determine how the regional climate model performed for representing rainfall events in the model, in terms of duration, intensity, and overall structure between all the event types.

The source to sink investigation of complex sedimentary systems necessitates chemical (stable isotope and elemental) and physical (modeling) analyses to elucidate temporal changes in volume and provenance of sediment supply. The stable isotopic composition of organic matter in continental margin sediments provides a useful, long-term record of environmental change. The Waipaoa River watershed, New Zealand, represents a system of interest due to its location on an active margin, very large sediment supply, and well known, relatively recent history of anthropogenic disturbance. Radiocarbon measurements of three continental shelf cores taken aboard the RV Marion Dufresne in January 2006 offshore from the river mouth suggest a record extending into the late Pleistocene, dating as far back as 14,000 years. Geographic information systems (GIS) modeling suggests large increases in erosion with reduction in landcover due to natural volcanic events and anthropogenic disturbances. Carbon and nitrogen isotope analyses of terrestrial sources including soil profiles, sedimentary rocks and riverine sediments from within the watershed suggest terrestrial processes such as shoreline progradation, hillslope erosion and gully incision, volcanic eruptions, and the capture of river tributaries are possibly influencing isotopic ratios and impacting the marine stratigraphic record. Unique isotopic signatures of soil profiles from disparate areas of the watershed could explain some isotopic variation seen in the cores as deviation in delivery volume from certain tributaries. Within the marine record in all three cores exists a distinct excursion of carbon isotopes to more positive values. Possible explanations for this include: 1) an increase in the flux of an isotopically heavy terrestrial fraction from the erosion of kerogen and 2) a decrease in the proportion of terrestrial organic matter due to dilution of river sediments with volcanic ash. Increasing nitrogen isotope values also within the excursion could suggest an increase in marine organic matter, however this could be the result of increased input of degraded refractory terrigenous organic matter or contributions of inorganic nitrogen.

Vertebrate fossils in the lower Horseshoe Canyon Formation are remains of dinosaurs, crocodilians, champsosaurs, turtles, and fish supported during the last ~2 m.y. of the Campanian by a coastal lake-strewn wetland occupying what is now south-central Alberta, Canada. Bones accumulated on the floodplain through attritional mortality and are preserved unweathered except for surface polish, scratches, and mottling characteristic of bioturbation during rapid burial in fine-grained sediment. Fossil-bearing sites cluster stratigraphically in laterally extensive horizons between thicker less fossil-rich intervals of similar fluvial strata. These horizons, formed by a long-term balance between bone supply, accommodation, and depositional rate, result from a newly recognized ?floodplain fill? mode of preservation for vertebrate fossils and are analogous to marine condensed sections. Like condensed sections, these fossiliferous horizons lie adjacent to lithostratigraphic surfaces created by stillstands in base-level. Together, hiatal surfaces and fossiliferous horizons reveal repeating rhythms in the facies distribution and fluvial architecture. These rhythms, ?packages? of strata bounded by hiatal surfaces, arose through two scales of variation in base-level: a grand-scale base-level cycle reflecting tectonic control during the construction of the clastic wedge, and a smaller ?package?-scale cycle reflecting Milankovitch control over local climate and precipitation. Both the fluvial architecture and the accumulations of fossils are a consequence of this change in accommodation and sediment supply through time. Fossil evidence does not indicate a faunal change through time, but changes in climate through time resulted in a reduction in organic-rich mudrocks and coal, an increase in soil development, and changes in the dominant configuration for fossil preservation from sparse bonebeds to microsites. Climate change was also investigated through stable oxygen isotopes in tyrannosaur tooth enamel phosphate, which daily recorded the response of surface (drinking) water to changes in humidity and temperature. The enamel isotopic record shows a transition from highly variable, seasonal climate to relatively constant conditions, consistent with the interpretation of change in the stratigraphy and taphonomy. This combined application of architectural stratigraphy, vertebrate taphonomy, and stable isotope paleoecology represents a new approach for paleontologists interested in evaluating changes through geologic time in paleoenvironment and animal communities in a fluvial succession.

Large-amplitude internal solitary waves (ISWs) are frequently observed in the northern South China Sea (SCS). In a project sponsored by the US Office of Naval Research, four moorings were deployed between the Luzon Strait and the Chinese continental shelf by Steve Ramp of the Naval Postgraduate School and David Tang of National Taiwan University from late April 2005 to May 2006. Several CTD sections were taken during April and July in 2005. Satellite pictures were also collected during that period. In this study, these data were used to examine the characteristics, generation, and propagation of ISWs. In the satellite images, monthly change in stratification may cause northward shift of the propagation path, and ISWs are more frequently observed in July than in April and May. Speed estimation shows that ISWs propagate faster in the deep basin than over the continental margin and near the ridge. The generation of internal tides correlates with the eastward tidal flow over the ridge, while ISWs are produced by northwestward tidal currents over the ridges in the Luzon Strait.

Single scattering albedo (omega), the ratio of scattering coefficient to total extinction coefficient, at UV wavelengths is an important aerosol radiative parameter in determining surface UV irradiance. Surface measurements of total and diffuse UV irradiance in the summer and fall of 1999 at the seven narrowband wavelength channels of an UV multifilter rotating shadowband radiometer (UVMFR-SR) at Black Mountain, NC were coupled with a tropospheric ultraviolet radiative transfer model to produce values of omega. Its value ranged from 0.53 ? 0.94 at 300 nm to 0.55 ? 1.00 at 368 nm. Error in this procedure decreases with increasing aerosol optical depth (AOD), from +/-0.19 at AOD = 0.05 to +/-0.02 at AOD=1.0. Values of omega were not found to be correlated with air mass origin. The current values of omega have a wider variation than values reported from a previous study at the same site, possibly attributable to changes in aerosol chemical composition over time. The value of omega was found to be quadratically correlated with wavelength. Little research has been conducted in the scattering and absorption properties of aerosols in the UV wavelengths, but what has been done suggests such a correlation is possible. More values of omega in the UV spectrum will allow for better estimation of this parameter for UV radiative transfer modeling and will lessen error in estimation of surface UV irradiances.

The blue crab (Callinectes sapidus) is an ecologically important estuarine predator and represents North Carolina?s most important commercial fishery. Recent fishery-dependent and ?independent data suggest the population is declining. The goal of this study was to increase our understanding of the status and population dynamics of the blue crab in NC by addressing the following objectives: (1) estimate population demographics of blue crabs in salt marsh creeks, (2) construct a discontinuous model of blue crab growth in NC using growth rates estimated from free-ranging blue crabs, and (3) provide a comprehensive stock assessment for the blue crab in NC. A series of complimentary laboratory and field studies assessed the nursery role of salt marsh habitats for the blue crab (Callinectes sapidus). Population demographics and movement patterns of juvenile and adult blue crabs were quantified in two tidal salt marsh creeks near Beaufort, North Carolina, USA during June ? October 2001. While there are many studies that report estimates of population density, mortality rates, or movement rates for blue crabs, this study represents one of the first attempts to estimate all quantities concurrently. Juvenile crabs were mobile within the interstices of the vegetated marsh surface during flood tide, and were equally distributed buried in intertidal marsh and adjacent mud areas during ebb tide. Juvenile crabs may experience a spatial refuge from cannibalism in the marsh surface since adult conspecifics are physically impeded by dense vegetation and rarely move far into marsh habitats. This spatial refuge in the vegetated marsh surface may be significant, since cannibalism represents a large source of mortality for this species. The relatively high use of the marsh surface by juvenile blue crabs, combined with a general lack of sampling these complex habitats, suggest that crab densities may be even higher in salt marsh systems than previously thought. Growth models commonly used in fisheries and ecological modeling assume growth is a continuous function of age. While this approach is appropriate for finfish, the validity of these models for crustacean species, which grow discontinuously, has been questioned. There is a critical need to compare the predictions of discontinuous and continuous models simultaneously to identify if potential biases are introduced by the assumption of continuous growth for the blue crab. The blue crab stock in North Carolina currently sustains heavy exploitation by the commercial fishery, and information on the recreational fishery is generally lacking. There has been a systematic increase in commercial landings from 1987-1999, followed by a period of reduced landings from 2000-2002. During this period fishery-independent indices of abundance have remained stable, or have shown a significant decline. In no case have any indices of abundance shown an increasing trend. Moreover, adult and spawning stock abundance (SSB) during 2000-2001 were at the lowest levels recorded since 1987, and the mean size of mature females has declined significantly during 1987-2003. Increases in the index of relative SSB in 2002-2003, however, may indicate a recovery. We detected a significant stock-recruit relationship for the blue crab in North Carolina using certain estimates of recruit abundance and recommend an urgent need for conservation of the spawning stock. We encourage decision makers to use the information and recommendations in this dissertation as soon as possible to manage the blue crab fishery in NC in a sustainable manner.

Considerable debate has surrounded the phylogenetic position of the large-bodied theropod Acrocanthosaurus atokensis from the Early Cretaceous Antlers Formation of North America. Many phylogenetic analyses place Acrocanthosaurus as the sister taxon to the smaller- bodied Allosaurus, known from formations in North America and Europe, whereas others recover it as a member of Carcharodontosauridae, a derived group of large-bodied allosauroids that inhabited Gondwana. Re-examination of a well-preserved skull of Acrocanthosaurus (NCSM 14345) has provided new information regarding the morphology of the palatal complex and inner surfaces of the skull and mandible, features that were obscured by a sediment matrix during a previous description. From this revised description, twenty-three new characters were identified and added to a data matrix (164 characters; 17 terminals), the analysis of which recovered a single most parsimonious tree placing Acrocanthosaurus as a derived member of Carcharodontosauridae. This hypothesis is supported by several shared cranial characteristics, including: a sinuous medial groove for the maxillary dental lamina; a small accessory process between the quadratojugal prongs of the jugal; and a dorsal curvature of the jugal ramus of the ectopterygoid. The phylogeny recovered by this analysis fit significantly better with the stratigraphic record than previous hypotheses that place Acrocanthosaurus as more closely related to Allosaurus, a finding supported by visual assessment of phylograms and stratigraphic consistency metrics. An analysis of the paleobiogeography of Allosauroidea found Asia to be the most likely ancestral area for the clade, consistent with previous analyses. Distribution of carcharodontosaurid ancestors likely reached both North America and Gondwana during the Valanginian or Barremian stages, with Europe providing a connection between the two continents.

Factors causing mortality in North Carolina's soft-shell blue crab industry were quantified and identified at 11 crab shedding systems across the state. Operators of crab shedding systems who shed peeler crabs (pre-molt crabs) that they had caught themselves (self-caught peeler crabs) experienced significantly lower crab mortality rates than operators who shed peelers that they had bought from different sources (purchased-peeler crabs). Molt stage had a significant effect on the mortality rates of self-caught peeler crabs, as early molt stage crabs (white-line peelers) suffered significantly higher mortality rates than late molt stage crabs (red-line peelers). Purchased male crabs experienced significantly higher mortality rates than purchased females crabs. Water quality did not have a significant effect on crab mortality. Male peeler crab mortality was not significantly affected by the presence or absence of female red-line peeler crabs. Male red-line peelers experienced significantly longer times to molt when male crab density was high. Results of this study may lead to improvements in crab shedding technology, increased profits, and better fishery management practices.

The occurrence of Appalachian cold air damming (CAD) is often associated with significant sensible weather impacts throughout the Carolinas and Virginia. CAD sensible weather, defined as below-normal maximum temperatures, overcast skies, fog, and reduced visibility, can often persist in the damming region for days. Furthermore, the confinement of a dome of low-level cold air along the eastern slopes of the Appalachians can create an environment ideal for freezing rain and sleet. Such potentially hazardous conditions necessitate accurate and timely forecasting in order to properly warn the public. Despite this need for reliable CAD prediction, accurate forecasting of the magnitude of sensible weather impacts and the timing of CAD demise are extremely challenging. Furthermore, many operational numerical weather prediction models do not accurately simulate CAD events. One of the more common problems associated with model forecasts is the premature erosion of the CAD cold dome and the underestimation of the duration of CAD sensible weather. A better understanding of the physical processes involved in cold dome erosion would lead to improved erosion forecasting by increasing forecaster awareness of the signs of CAD erosion and by isolating physical processes that may be poorly handled by operational models. <br> <br>One objective of this research is to describe the common synoptic patterns evident during the erosion period of CAD events. These synoptic erosion scenarios are representative of the physical mechanisms contributing to cold dome erosion. To accomplish this objective, 89 classical CAD events detected by the algorithm of Bailey et al. (2003) were grouped according to similarities in sea-level pressure and surface potential temperature fields. Composite maps of each group were created, resulting in five CAD erosion scenarios: (1) Northwestern Low, (2) Cold Frontal Passage, (3) Coastal Low, (4) Residual Cold Pool, and (5) Southwestern Low. High levels of statistical significance were associated with the dominant synoptic features in all scenarios except the Southwestern Low, suggesting that the remaining four scenarios effectively represented distinct erosion patterns. Several potential erosion mechanisms could be inferred from the evolution of dominant synoptic features in each erosion scenario. Multiple erosion mechanisms may be simultaneously contributing to cold dome erosion for any one given scenario. <br> <br>The second objective involved detailed case studies of three CAD events in order to more closely examine erosion mechanisms. The first case was an example of the Coastal Low erosion scenario, the second case was representative of the Northwestern Low erosion scenario, and erosion of the third case was multi-faceted and not clearly classifiable. Detailed examination of observations and EDAS analyses revealed that multiple erosion mechanisms were contributing to the weakening of the capping inversion above the cold dome and promoting the erosion of the CAD event. In the Coastal Low case, cold advection aloft led to a decrease in the potential temperature difference across the inversion, indicating erosion from the top of the cold dome down to the surface. Comparatively, the inland progression of a coastal front, in association with surface divergence, corresponded to an increase in surface temperatures and a weakening of the inversion during the Northwestern Low case study. This development was more indicative of erosion from the surface upwards. <br> <br>The performance of NCEP Eta Model forecasts during the three CAD events was evaluated. Consistent with the findings of previous research, the Eta Model eroded the cold dome prematurely for all three cases, and surface temperature were consistently overestimated. Control run simulations using the PSU/NCAR MM5 Model were performed for the Coastal Low and Northwestern Low cases. The control run simulations showed improved accuracy over the Eta Model forecasts in the representation of CAD erosion. However, erosion was still premature in comparison to observations. For both CAD events, overestimated values of shortwave radiation appeared to correlate with the decrease in model inversion strength. <br> <br>Finally, two sets of sensitivity tests for the Coastal Low case using the MM5 model were designed to test the sensitivity of model performance to alterations in certain physics parameterizations. The first sensitivity test involved altering the model values of cloud albedo, based on speculations that the overestimation of surface temperatures in the Eta Model was a result of the interaction between clouds and shortwave radiation. As hypothesized, the simulation in which cloud albedo was decreased produced the warmest surface temperatures. The second sensitivity test involved altering the PBL schemes used in the MM5 control run. It was found that the simulated vertical structure of the atmosphere did vary according to the PBL scheme, as anticipated. <br> <br>Although some of the alterations made to the MM5 control run for the sensitivity tests did improve the representation of certain features, the model continued to erode the cold dome earlier than observed. Comparisons of the MM5 simulations to the corresponding Eta Model forecasts revealed that none of the alterations to the MM5 control run produced the magnitude of error evident in the Eta Model.

Globally, the largest source of atmospheric NH3 is domestic animal waste contributing 20-35 Tg of nitrogen per year. In North Carolina, hog waste accounts for 47% of all ammonia emissions in North Carolina. This is the result of a huge increase in hog population since the 1980?s from 3 million to 10 million. Currently swine waste is managed using Lagoon and Spray Technology (LST) also known as ?conventional? technology. A LST uses anaerobic lagoons to store the hog waste, and effluent from lagoons is sprayed on surrounding crops as a source of nutrients. This technology lead to a number sources of ammonia emissions, thus there are a number of environmental problems associated with swine facilities. The need for developing sustainable solutions for managing the hog waste problem is critical for shaping the future of hog farms in North Carolina. As a result of this, an agreement between the North Carolina Attorney General and several farming companies was reached to develop environmentally superior technologies (EST?s) for swine facilities. The objective of this study was to quantitatively compare the emissions from the water-holding structures at the two LST farms (Moore farm and Stokes farm) and the three EST farms, and to evaluate the effectiveness of each technology. The three potential EST?s were (1) EKOKAN: Up-flow Bio-filtration system, located at Brown?s of Carolina # 93, (2) BEST: Solids separation/gasification for energy and ash recovery centralized system, located at Corbett # 1,3,4 farms, and (3) Super Soils: Solids separation/nitrification-denitrification/soluble phosphorus removal/solids processing system, located at Goshen Ridge farm. Measurements of NH3 flux were limited to two, two-week long periods, representing warm and cold seasons. These were obtained by using a dynamic flow-through chamber system interfaced to a mobile laboratory containing the ammonia analyzer and the data acquisition system. During the sampling period, environmental parameters such as lagoon temperature, lagoon pH, and TAN were measured, as well as meteorological parameters such as wind speed, wind direction, air temperature, relative humidity, and solar radiation. In order to make a comparison of LST and EST?s, an adjustment for differing environmental conditions was needed. This was achieved by the development of a conventional observational statistical model, which was developed by multiple linear regression analysis based on continuous flux measurements from two conventional farms during a warm and cold season. Ammonia emissions from both conventional and EST farms were normalized to the nitrogen excretion (E) at the hog farms to express the emissions as % E. Potential reductions in ammonia were evaluated by comparing % EEST at EST farms with %ECONV at conventional farms. Overall, all three EST?s were found to be significant in reducing ammonia emissions. Super Soils was found to be the most effective, with NH3 emission reductions of 94.7% in the warm season, and 99% in the cold season. EKOKAN was found to be the next most effective, with reductions of 71.7 % and 42.7 % for the summer and spring sampling periods, respectively. The two BEST technologies were the least effective. There were large reductions for both Corbett # 1 and Corbett # 3,4 in the fall sampling period, 71.1% and 39.6% respectively. There were through extremely low reductions in the winter sampling period, with reductions of 13.6% for Corbett # 1 and 7.5% for Corbett # 3,4, respectively.