Warm seclusions are large midlatitude storms that have the potential to substantially influence the turbulent heat fluxes and global energy budget. These storms have not been previously investigated from an energy and flux perspective. They have large areas of strong surface winds and rapidly moving cold fronts, which are associated with large air-sea differences of temperature and humidity. These regions contain large air-sea fluxes of latent and sensible heat. Therefore, errors in model representation of warm seclusions may introduce significant bias and uncertainty to the energy budget. The turbulent heat fluxes associated with three specific warm seclusions in different ocean basins are examined through an intercomparison of satellite- derived flux data and numerically derived flux data. The satellite data includes the SeaFlux version 0.75 data derived from SSM/I (Special Sensor Microwave/Imager), and model-derived reanalysis data includes CFSR, ERA-Interim, MERRA, and NCEP-R2 reanalysis data sets. Latent and sensible heat fluxes are computed in a physically consistent manner though the use of a bulk flux parameterization A single warm seclusion, which typically lasts between three and seven days, is responsible for approximately one quarter of the total time-integrated monthly fluxes for the ocean basin containing the warm seclusion, depending on the storm and data set under consideration. The large area of extremely large fluxes is associated with the mature phase of the cyclone. Proper representation of these fluxes is critical to determining accurate monthly- averaged, basin-wide fluxes. / A Thesis Submitted to the Department of Earth, Ocean and Atmospheric Science in Partial Fulfillment of the Requirements for the Degree of Master of Science. / Summer Semester, 2011. / March 29, 2011. / Satellite, Reanalysis, Air Sea Interaction, Turbulent Heat Fluxes, Intercomparison, Warm Seclusion / Includes bibliographical references. / Mark A. Bourassa, Professor Directing Thesis; Carol Anne Clayson, Professor Co-Directing Thesis; Philip Sura, Committee Member.

Lightning data provide a valuable tool for examining interactions between multi-scale weather phenomena. Weather events are determined by complex atmospheric interactions at various spatial and temporal scales. Long-term climatologies facilitate discussion of average meteorological conditions and can help isolate the relative influence of multi-scale systems (e.g., synoptic scale, mesoscale, etc.) on local weather patterns. Lightning datasets allow the development of large-scale, long-term climatologies. These lightning climatologies then are compared with additional atmospheric observations (e.g., numerical models and radar) to examine the regional, seasonal, and storm-scale variability of thunderstorm characteristics. The National Lightning Detection Network (NLDN) underwent a major upgrade during 2002–2003 that increased its sensitivity and improved its performance. Therefore, this study applies the same methodology to pre- and post-upgrade NLDN datasets to allow direct quantitative comparisons between them and thereby examine the influence of the recent upgrade on regional distributions of cloud-to-ground (CG) lightning characteristics. Although seasonal variability must be understood to better define apparent relationships between storm properties and lightning production, seasonal differences are best described on the regional scale. Therefore, this study also examines Florida's seasonal, regional, and storm-scale CG variability during 2004–09. Since lightning data are recorded instantaneously and typically reported every minute, they also provide valuable information on storm-scale development and evolution. Automated procedures are developed to create grids of lightning and radar parameters, cluster individual storm features, and data mine the lightning and radar attributes of many individual storms. These procedures facilitate detailed analysis of relationships between lightning and radar-derived parameters in many individual storms in the Mid-Atlantic Region during 2007–09. A major goal of this research is to combine information about the near-storm environment, radar-defined storm structure, and both intra-cloud (IC) and CG lightning characteristics to better quantify relationships between storm structure, lightning production, and storm severity. / A Dissertation Submitted to the College of Arts and Sciences in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. / Spring Semester, 2011. / November 09, 2010. / Lightning, Severe Storms, Radar, NLDN, WDSS-II, GIS / Includes bibliographical references. / Henry E. Fuelberg, Professor Directing Dissertation; J. Anthony Stallins, University Representative; Carol Ann Clayson, Committee Member; Robert E. Hart, Committee Member; Guosheng Liu, Committee Member.

The need for a high-resolution precipitation database over Florida is evident by the ever-increasing impact of water resources on society. The Multisensor Precipitation Estimator (MPE) software was developed by the National Weather Service to combine hourly rain gauge- and radar-derived precipitation estimates optimally. The MPE procedure creates hourly rainfall estimates on a 4 x 4 km&178; grid. This research uses the final product from the MPE procedure (MMOSAIC) to create a high-resolution rainfall climatology over the Florida peninsula from 1996 through 2001. An objective rain gauge quality control (QC) procedure is developed to minimize the amount of erroneous gauge data that is input to the MPE procedure. This objective scheme compares the gauge data with corresponding raw radar data. A rigorous examination of rain gauge data and the encompassing radar-derived rainfall estimates revealed four main scenarios that are included in the QC procedure. The scenario responsible for removing the most data occurs when a radar-derived estimate reports heavy rainfall (> 1 in./h), while the gauge within that radar grid cell reports a value near zero. The QC procedure removes most of these suspect gauge data, thereby limiting their corrupting effect on the bias calculations within the MPE procedure. The other three QC scenarios removed a smaller number of gauges that would have adversely affected the calculations. 1 in./h), while the gauge within that radar grid cell reports a value near zero. The QC procedure removes most of these suspect gauge data, thereby limiting their corrupting effect on the bias calculations within the MPE procedure. The other three QC scenarios removed a smaller number of gauges that would have adversely affected the calculations. An analysis of the different rainfall products produced by MPE demonstrates the positive impact of the extensive quality control efforts. An independent set of rain gauges is used to evaluate the MPE products statistically for selected periods during 1999 and 2001. Results show that the final MPE product (MMOSAIC) outperforms both the radar and gauge data alone. Gauges alone generally cannot accurately represent the spatial details of warm season convective type precipitation events. Conversely, radar data depict convective precipitation events quite well; however, radars do a poor job of detecting cold season stratiform precipitation events. Analyses reveal that the MMOSAIC product utilizes the strengths of the gauges and the radars in an optimum way. Seasonal case studies comparing the independent set of gauge observations to the final MPE product show that there is good agreement between the two hourly sources (i.e., biases &61; -0.004 in., r &61; 0.78, and RMSD &61; 0.12 in.). Agreements are found to improve over daily and monthly accumulation periods. Results of this study describe the problems and uncertainties associated with quantitatively measuring Florida rainfall through a multisensor analysis / A Thesis submitted to the Department of Meteorology in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester, 2004. / June 21, 2004. / Rainfall Variability, MPE Verification / Includes bibliographical references. / Henry E. Fuelberg, Professor Directing Thesis; Paul H. Ruscher, Committee Member; Jon E. Ahlquist, Committee Member.

Ocean vector winds measured by the SeaWinds scatterometer onboard the QuikSCAT satellite can be validated with in situ data. Ideally the comparison in situ data would be collocated in both time and space to the satellite overpass; however, this is rarely the case because of the time sampling interval of the in situ data and the sparseness of data. To compensate for the lack of ideal collocations, in situ data that are within a certain time and space range of the satellite overpass are used for comparisons. To determine the total amount of random observational error, additional uncertainty from the temporal and spatial difference must be considered along with the uncertainty associated with the data sets. The purpose of this study is to quantify the amount of error associated with the two data sets, as well as the amount of error associated with the temporal and/or spatial difference between two observations. The variance associated with a temporal difference between two observations is initially examined in an idealized case that includes only Shipboard Automated Meteorological and Oceanographic System (SAMOS) one-minute data. Temporal differences can be translated into spatial differences by using Taylor's hypothesis. The results show that as the time difference increases, the amount of variance increases. Higher wind speeds are also associated with a larger amount of variance. Collocated SeaWinds and SAMOS observations are used to determine the total variance associated with a temporal (equivalent) difference from 0 to 60 minutes. If the combined temporal and spatial difference is less than 25 minutes (equivalent), the variance associated with the temporal and spatial difference is offset by the observational errors, which are approximately 1.0 m2s-2 for wind speeds between 4 and 7 ms-1 and approximately 1.5 m2s-2 for wind speeds between 7 and 12 ms-1. If the combined temporal and spatial difference is greater than 25 minutes (equivalent), then the variance associated with the temporal and spatial difference is no longer offset by the variance associated with observational error in the data sets; therefore, the total variance gradually increases as the time difference increases. / A Thesis submitted to the Department of Earth, Ocean and Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2010. / October 25, 2010. / QuikSCAT, Winds, SAMOS, Error variance, Collocation / Includes bibliographical references. / Mark A. Bourassa, Professor Directing Thesis; Vasubandhu Misra, Committee Member; Zhaohua Wu, Committee Member; Shawn R. Smith, Committee Member.

This study evaluates the impacts of two different precipitation types on stage heights from a fully integrated and distributed, physically based hydrologic model - MIKE SHE. Simulations using a network of South Florida Water Management District (SFWMD) rain gauge measurements in the form of Thiessen polygons are compared with those using a &126; 4 x 4 km gridded historical precipitation database prepared at Florida State University (FSU). The FSU procedure employs a version of the National Weather Service (NWS) Multi-sensor Precipitation Estimator (MPE) algorithm. Each precipitation input is at both hourly and daily intervals. Simulated stages from MIKE SHE are evaluated over the relatively flat Big Cypress Basin (BCB) which has a maximum elevation range of &126; 12.5 m over a 1661 km&178; area. Daily averaged stage heights are analyzed at four stream gauge sites along canals within the BCB using seasonally based three-month model runs between 2003 to 2005 plus two separate case studies containing significant rainfall accumulations. Results show a high correlation between precipitation values of the FSU MPE database and the SFWMD rain gauges because the rain gauge data are incorporated into the MPE algorithm. Therefore, stage hydrographs and statistical properties of the stages generally are very similar between the two precipitation datasets at both temporal resolutions. Slightly greater differences are found between observed stages and those from the four versions of modeled output. The high resolution FSU MPE precipitation estimates generally provide improved stages compared to the SFWMD rain gauges. The use of hourly temporal resolution input impacts the timing and magnitude of the resulting stages. The modeled stages based on hourly precipitation values generally provide a faster hydrologic response and better simulate the observed stages than do daily values during extreme rainfall events (e.g., Hurricane Wilma). We believe that improved multi-sensor products and quality control procedures can be beneficial to enhancing water management decisions and flood forecasting within the SFWMD. / A Thesis submitted to the Department of Meteorology in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2008. / November 6, 2008. / Precipitation Comparison, Watershed Management / Includes bibliographical references. / Henry E. Fuelberg, Professor Directing Thesis; Phillip Cunningham, Committee Member; Guosheng Liu, Committee Member; Chandra S. Pathak, Committee Member.

The abrupt temperature rise in the beginning of the Holocene is the most dramatic climatic change of the last 80,000 years. It is suggested here that the change is due to the abrupt opening of the Bering Strait which we hypothesize was initially jammed with icebergs, common during the termination of the last glaciation. Once sea-level rose beyond a critical point, the dam broke allowing low salinity water (which dominated the Atlantic during the Younger Dryas) to be flushed out of the Atlantic. This then, allowed the global wind field to force more Southern Ocean water into the Atlantic. A new analytical coupled ocean-atmosphere model was developed and applied to the North Atlantic, in an attempt to quantify the temperature change due to the opening and closing of the Bering Strait. Heat, salt and mass are all conserved within a box in the North Atlantic. A convection condition allows water to enter the deep layer, and the ocean and atmosphere are connected through their Ekman layers. Restarting convection, through the opening of the Bering Strait, increases mean oceanic and atmospheric temperatures by 2-4 ºC and 14-17 ºC, respectively. These values are favorably compared to those found in both the CEREGE alkenone and GISP II Greenland ice core records. The temporary damming/jamming of the Bering Strait due to large icebergs was examined using a simple laboratory box model. Results show the stability of the dam to be dependent on the rate of sea level rise, which at 1 cm yr -1, should be sufficiently slow to allow a temporary dam to exist for several thousands of years. Sea ice probably fused icebergs together, and through ridging could have created a 30-40 m vertical ice wall. / A Dissertation Submitted to the Department of Oceanography in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. / Fall Semester, 2006. / July 21, 2006. / Deep-Water Formation, Meridional Overturning Cell, Heinrich Events, Temporary Daming, Climate Stability, Convection / Includes bibliographical references. / Doron Nof, Professor Directing Dissertation; Christopher Hunter, Outside Committee Member; William Burnett, Committee Member; Allan J. Clarke, Committee Member; Georges L. Weatherly, Committee Member; James J. O’Brien, Committee Member.

A medium complexity, nitrogen-based ecosystem model is developed in order to simulate the ecosystem in the northeast tropical Pacific. Several physical processes have major impact on the ecosystem in this region, most importantly intense wind jets along the coast and upwelling at the Costa Rica Dome (CRD). The ecosystem model is run "offline", using a realistic physical ocean model hindcast as input. The physical model is a subdomain of the global Navy Coastal Ocean Model, which is a hybrid sigma-z level model. The model assimilates Modular Ocean Data Assimilation System temperature and salinity profiles derived from altimetry and sea surface temperature data. The model is forced by daily heat and momentum fluxes, and therefore captures short-term wind events such as the Tehuantepec jet. Because the model has high horizontal resolution (~1/8 degree) and assimilates sea surface height data, it has a realistic representation of eddies and mesoscale variability. The ecosystem model includes two nutrients (nitrate and ammonium), two size-classes of phytoplankton, two size-classes of zooplankton, and detritus. The model is run for 4 years from 1999 to 2002, with analyses focused on 2000-2002. The model is validated using SeaWiFS data and ship-based observations from the STAR-cruises (Stenella Abundance Research Project) of 1999 and 2000. The northernmost and most intense of the wind jets along Central America is the Tehuantepec jet. The Tehuantepec jet is responsible for upwelling large amounts of nutrient rich water south of the Gulf of Tehuantepec. The jet also occasionally produce large anti-cyclonic eddies that transport organic matter away from the coast. Because organic matter that is transported into the open ocean will eventually sink to the deep ocean, this has implications for the carbon export in this region. The model results are used to calculate cross-shelf fluxes in this region in order to estimate how much organic material is transported across the shelf break. Results show that at the Gulf of Tehuantepec there is high offshore export of organic material, particularly during eddy generation events, but also in fall. The highest export is on the order of 10 Mg C per meter of coastline per day and happens during eddy events. During these events there is a comparable onshore flux to the south of the gulf. Typically there is onshore flux to the south of the gulf during the summer. The model estimated transport away from the coast at the Gulf of Tehuantepec is 167 Tg C/year, and the onshore transport to the south of the gulf is 704 Tg C/year. The second subject of interest is the CRD. In this region, upwelling at the surface is caused by Ekman upwelling during the summer, although the dome is thought to be present at depth throughout the year. The doming of the isotherms below the thermocline is a result of vortex stretching and is decoupled from the wind-driven processes at the surface. A mass-balance budget is calculated at the CRD, and the horizontal and vertical fluxes are related to the abundance of plankton at the dome. There is upwelling (7.2X10-2 Sv ) at the dome throughout the year, but around the location of the dome (90° W), the upwelling is largest in the winter. Further west, input of nutrients from below is larger in the fall and summer. The results suggest that about 80% of the nitrate that is supplied to the dome during summer is actually brought up to the west of the dome and transported eastward by the North Equatorial Counter Current. / A Dissertation Submitted to the Department of Oceanographyin Partial Fulfillment of Therequirements for the Degree ofdoctor of Philosophy. / Spring Semester, 2005. / March 14, 2005. / Physical-Biological Interactions, Marine Ecosystem Modeling, Pacific Ocean, Gulf Of Tehuantepec, Costa Rica Dome, Cross-Shelf Transport, Eddies / Includes bibliographical references. / James J. O'Brien, Professor Directing Dissertation; Gordon Erlebacher, Outside Committee Member; William K. Dewar, Committee Member; Nancy H. Marcus, Committee Member; Richard L. Iverson, Committee Member; Eileen E. Hofmann, Committee Member.

Submarine groundwater discharge (SGD) assessments conducted both in the laboratory and at a field site in the northeastern Gulf of Mexico, using a continuous-heat type automated seepage meter (seepmeter) have shown that the device has the potential of providing long-term, high-resolution measurements of SGD. The improvements on the device using a simple inexpensive laboratory set up, have shown that: (1) connecting an extension cable to the seepmeter has a negligible effect on its measuring capability and, (2) influence of very low temperature (≤ 3 ºC) on seepmeter measurements can be accounted for by conducting calibrations at such temperatures prior to field deployments and, (3) salinity had no significant effect on the performance of the seepmeter. Calibration results from fresh water and sea water showed close agreement at a 95% confidence level significance between the data sets from the two media (R2 = 0.98). The observed artifacts on seepmeter measurements associated with Bernoulli-induced flow, the vertically directed flow arising due to water movement across topographic features can significantly be reduced by burying (or submerging) the seepmeter to nearly the same level as the sediment topography. While the study revealed that in general wind speeds > 6 m/s were associated with enhanced SGD measurements in seepmeters with buried and unburied benthic chambers, the influence was greater in the unburied meters, and more pronounced for SGD rates 6 m/s were associated with enhanced SGD measurements in seepmeters with buried and unburied benthic chambers, the influence was greater in the unburied meters, and more pronounced for SGD rates Study of the Sarasota Bay (SB) system revealed SGD advection rates ranging from 0.7 to 24.0 cm/day, except for rare isolated hot spot occurrences where higher rates were observed. In general, SGD estimates were relatively higher in the middle and south regions (5.9 – 24.0 cm/day) compared to the north region (0.7 – 5.9 cm/day). Although no obvious seawater nutrient concentration trend was revealed, the average N/P ratio was higher in the north compared to the middle and south regions of the SB system. The importance of SGD was evident in that about 40% of the regional nutrient fluxes were observed in the north while ~ 60% occurred in the middle and south regions combined. The latter two regions also had the highest overall nutrient flux per water volume ratio, compared to the north region, thus making them potentially more vulnerable to eutrophic conditions. On average, we estimate about 27% of total dissolved N in the SB system was derived via SGD. / A Dissertation Submitted to the Department of Earth, Ocean and Atmospheric Science in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. / Fall Semester, 2010. / August 26, 2010. / hydrology, Submarine groundwater discharge, groundwater, seepage meter, seepage meter artifacts, Florida, nutrients, nutrient fluxes, marine environment, nearshore, processes, measurements, coastal zone, Turkey Point, Sarasota, groundwater discharge quantification, Gulf of Mexico, biogeochemistry / Includes bibliographical references. / William C. Burnett, Professor Directing Dissertation; Xiaolong Bill Hu, University Representative; Jeffrey P. Chanton, Committee Member; William M. Landing, Committee Member; Joel E. Kostka, Committee Member.

This study has evaluated an existing hybrid three-dimensional variational ensemble transform Kalman filter (3DVAR-ETKF) ensemble data assimilation system using the Weather Research and Forecasting (WRF) model in realistic numerical weather prediction experiments. The study was divided into three parts: Part one assessed the skill of the ETKF ensemble generation scheme with and without implicit mode error included in the ensemble. Part two assessed the benefit of including flow-dependent information into the hybrid cost function. Part three proposed an alternative to ETKF and tested its performance in cycling experiments. The ETKF perturbations as an ensemble-generation scheme performed well in single and multi-physics ensemble approaches. The multi-physics ETKF ensemble performed best maintaining the appropriate variance and dependence on covariance inflation. The multi-physics ETKF ensemble was characterized by larger (smaller) error growth (reduction) during the model integration than the single-physics ensemble. Using the ensemble mean as the first guess in the 3DVAR cost function significantly improved the skill of the analyses. Tuning the static 3DVAR background error covariances using the ETKF ensemble perturbations instead of time-lagged perturbations improved the skill of the deterministic and ensemble 3DVAR analyses as measured by 12- through 48-h deterministic forecast skill. Incorporating ensemble-based flow-dependent error covariances from limited 20-member ensembles into the hybrid cost function added skill to the analyses. This added skill was in addition to that achieved by using the ensemble mean as the first guess and using the tuned background error covariances. The greatest improvements in analysis skill were observed when a multi-physics ensemble was used to supply the error covariances to the hybrid cost function. Vertical localization added some skill to the analyzed wind speeds, mostly at longer lead times and when the localization length scale is less restrictive. The proposed hybrid Lanczos ensemble filter (HLEF) ensemble generation scheme was shown to be equivalent to the ETKF scheme when no inflation was applied and the HELF perturbations did not include the effect of covariance localizations or hybridization. Both vertical and horizontal covariance localization in the HLEF perturbations ameliorated the under estimation of analysis uncertainty. 10-day cycling experiments with inflated and localized HLEF perturbations required less than 30% of the magnitude of the inflation required by ETKF. Experiments that addressed the possibility of producing analysis perturbations that are consistent with the hybrid variational cost function produced encouraging results. / A Dissertation Submitted to the Department of Earth, Ocean and Atmospheric Sciences in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. / Spring Semester, 2011. / March 28, 2011. / Physics Uncertainty, 3DVAR, Hybrid, Lanczos, ETKF, Ensemble Data Assimilation, Data Assimilation / Includes bibliographical references. / Henry E. Fuelberg, Professor Directing Dissertation; I. Michael Navon, University Representative; Robert Hart, Committee Member; Jon E. Ahlquist, Committee Member; Xiang-Yu Huang, Committee Member; Guosheng Liu, Committee Member; P. Anil Rao, Committee Member.

Submarine groundwater discharge (SGD) is an important pathway for trace element and nutrient cycling in the coastal ocean. I use a combination of hydrological and geochemical tracer observations to gain insights into the natural and anthropogenic mechanisms driving SGD into coastal water bodies. Nutrient measurements in a subterranean estuary (STE) were used to discuss the biogeochemical controls of SGD endmember concentrations and to derive inputs associated with fresh and saline SGD. 222Rn, CH4, and associated variables in seawater were monitored nearly continuously at a coastal site in the Gulf of Mexico for almost two years. Surprisingly, the variability of 222Rn and CH4 over short (e.g., hourly) time scales was generally comparable to or even more pronounced than fluctuations over much longer (e.g., monthly) time scales. While high tracer concentrations usually occurred during low tide and low tracer concentrations during high tide, this pattern was occasionally inverted or absent indicating that no single model can be used to describe the entire dataset. This implies that seasonal investigations of SGD tracers in the coastal ocean may be masked by short-term variability. Modeled SGD patterns were strongly associated with the neap-spring tidal cycle, at least during a period of extreme drought when minimum external disturbances were present. Multiple independent approaches used to separate the relative contribution of fresh and saline SGD indicated that transient marine forces, likely tidal pumping, dominate benthic advective exchange at this coastal plain site. I also tested whether biogeochemical processes in a STE alter nutrient concentrations that are discharged into the ocean via SGD. Nutrient distributions were consistent with a sequence of reactions in a narrow (~2 m) surface layer where nitrate is initially exhausted (likely due to denitrification), organic nitrogen is remineralized releasing ammonium, and some DOC remains. Nutrient cycling in this STE was primarily fueled by oxygen and labile organic matter supplied by tidal pumping of seawater into the coastal aquifer. Even though fresh SGD accounted for only ~5% of total volumetric additions, the interaction between fresh SGD with components in the STE provided 22-34% of DOC and ~50% of nitrogen inputs, with the remainder associated with recirculated seawater. While SGD volumetric inputs are similar seasonally, changes in the biogeochemical conditions of this coastal plain STE led to higher summertime nutrient fluxes, suggesting a link between coastal primary productivity and nutrient production. Finally, I applied naturally-occurring geochemical tracers (222Rn, 223Ra, 224Ra, 226Ra, CH4, 18O, and 2H) to assess anthropogenic-driven groundwater discharge in Mangueira Lagoon, Brazil. Modeling of radon inventories indicated that groundwater advection rates in the numerous irrigation canals are 2 orders of magnitude higher than along the lagoon shoreline. In spite of the relatively small area of the canals, they contributed nearly 70% of the total (~57,000 m3/d) groundwater input into the entire Mangueira Lagoon. Dredging of these canals cut through aquitards which previously restricted upward advection from the underlying permeable strata. In spite of the small volume contribution (~2% of precipitation), groundwater accounted for 50-70% of major ion inputs into the lagoon. The irrigation channels may therefore represent an important but previously overlooked source of nutrients and other dissolved chemicals derived from agricultural practices into this and other lagoons. / A Dissertation Submitted to the Department of Oceanography in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy. / Fall Semester, 2008. / October 16, 2008. / Radon, Nutrients, Geochemical Tracers, Permeable Sediments / Includes bibliographical references. / William C. Burnett, Professor Directing Dissertation; Jeffrey Chanton, Professor Co-Directing Dissertation; Bill Hu, Outside Committee Member; Thorsten Dittmar, Committee Member; Philip Froelich, Committee Member; Markus Huettel, Committee Member.