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.

Mid-ocean ridge interactions with hotspots strongly affect mantle flow processes. This study analyses the anomalies produced as a result of the interaction between a hotspot and an oceanic ridge-ridge-ridge triple junction, in close proximity to one another. The complex three dimensional (3D) nature of the Azores Triple Junction (ATJ), in which two near-collinear faster-spreading ridges are joined orthogonally with a slower-spreading ridge, provides an excellent opportunity to quantify the effect of triple junction geometry on along-axis magmatic accretion and mantle dynamic processes as a result of the interaction with a hotspot. For the ATJ, the faster-spreading ridges are two branches of the Mid-Atlantic Ridge (MAR), and the slower-spreading ridge is the Terceira Rift (TR). Using shipboard bathymetry and satellite free-air gravity, we obtain mantle Bouguer anomaly (MBA) by eliminating from free-air gravity the attractions of seafloor topography and a reference crust. Along the TR, the Azores hotspot has a maximum MBA axial gravity low of -100 mGal, suggesting localized crustal thickening, elevated mantle temperatures and/or low density mantle. The entire Azores plateau along the TR is associated with a large (~80 mGal) broad low. Dispersion of plume material along the TR, a distance in the range of 550 km, is likely minimized by the rift system's obliqueness, immature nature and hyper-slow spreading rate, as well as the presence of the Gloria Fracture Zone. Further, along-axis profiles along the TR suggest that MBA shows a strong dependence on the tectonic segmentation of the ridge axis. / A Thesis Submitted to the Department of Geological Sciences in Partial Fulfillment of the Requirements for the Degree of Master of Science. / Spring Semester, 2009. / March 6, 2009. / Lithosphere, Geochemical, Crust, Compositional, Oceanic, Continental, Volcanism, Tomographic / Includes bibliographical references. / Jennifer Georgen, Professor Co-Directing Thesis; Jim Tull, Professor Co-Directing Thesis; Vincent Salters, Committee Member; William Parker, Committee Member.

The Citronelle Formation is the most widely occurring, surficial geologic unit along the northeast Gulf of Mexico. It is a siliciclastic unit consisting primarily of sands and gravels with varying amounts of clay and minor amounts of mica and heavy minerals. Historically, the unit has been thought to be a fluvial deposit of Pliocene age. Evidence presented here suggests, at least in part, a marine origin. In some pits and exposures in southern Walton and Okaloosa Counties in western Florida, sediments that are referred to the Citronelle Formation contain well preserved Ophiomorpha, bivalve mollusk casts, shark teeth, terrestrial vertebrate fossils and other trace fossil remains. Various types of bedding, including cross bedding, occur. These apparent nearshore marine depositional facies are the focus of this investigation which will attempt to determine the paleo- environmental depositional regimes, age, and how this facies relates to the Cirtonelle Formation. Field work was conducted and data were gathered from exposures and outcrops within the study area. Stratigraphic sections were measured and described. Where feasible, sediment samples were collected for sieve analysis. Further sampling of trace fossils (Ophiomorpha) and body fossils was conducted for analysis. Cross-bedding orientation was recorded from one locality to determine predominant paleo-current direction. These data, when combined, support the hypothesis that these sediments that have been mapped as Citronelle Formation represent nearshore, marine facies. However, their placement in the Citronelle Formation still remains questionable due to the lithologic similarity of overlying and underlying units. / A Thesis submitted to the Department of Geological Sciences in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester, 2009. / April 7, 2009. / Granulometry, Siliciclastic, Ophiomorpha, Citronelle / Includes bibliographical references. / Sherwood W. Wise, Professor Directing Thesis; Anthony J. Arnold, Committee Member; Joseph F. Donoghue, Committee Member; Stephen J. Kish, Committee Member.

Ice and snow particles have a great, yet poorly understood impact on the Earth's climate system. One of the difficulties of studying snow particles is their irregular shape. While spheres and even oblate spheroids backscatter radiation in a consistent manner, irregularly shaped objects do not. Due to the complexities of snowflakes, they are often assumed to be spherical for both satellite retrieval and modeling purposes. This can introduce error in many studies. While there are several aggregate snowflake models in existence, many use spheres as a building block for the snowflake. This is inaccurate as most snowflakes are comprised of a combination of bullet rosettes, plates, columns, and dendritic snow crystals. Furthermore, most studies do not have constraints in place to make sure that snowflakes are of the correct size and density as observed from field studies. None of the theoretical models examined in this study analyze the single-scattering properties of the flakes. In order to improve upon previous models, this study creates an aggregate snowflake using 200 ìm and 400 ìm 6-bullet rosette crystals. These crystals and resultant flakes are required to follow established size-density relationships obtained from numerous field studies. In addition, the flakes must also be of similar fractal dimension determined from other case studies. The single-scattering properties of these flakes are then determined from the discrete dipole approximation. / A Thesis submitted to the Department of Meteorology in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester, 2010. / April 13, 2010. / dda, Extinction Coefficient, Scattering Coefficient, Absorption Coefficient / Includes bibliographical references. / Guosheng Liu, Professor Directing Thesis; Robert G. Ellingson, Committee Member; Paul Ruscher, Committee Member.

The tectonic separation of Australia from Antarctica is a key constraint on the development of the Antarctic Circumpolar Current (ACC) during the Cenozoic. The ACC plays a critical role in global climate thermally isolating Antarctica and its initiation is hypothesized to have crossed a critical global climate boundary resulting in initial Antarctic ice sheet growth (Kennett, Houtz et al., 1975; Exon, Kennett, Malone et al., 2001). The relatively shallow Tasmanian Gateway is one of the few places in the Southern mid to high latitudes where fairly complete, carbonate-rich sequences can be drilled detailing development of the ACC. The upper Oligocene and Miocene sediments recovered by Ocean Drilling Program (ODP) Leg 189 are rare when compared to other Southern Ocean drilling sites in terms of biotic richness and continuous sedimentation through the Miocene (Exon, Kennett, Malone et al., 2001). The Miocene has been characterized as a warm interval with significant cooling taking place in the middle Miocene with the permanent emplacement of the East Antarctic Ice Sheet (EAIS) (Shackleton and Kennett, 1975). Evidence for periods of ice sheet growth and decay prior to the mid-Miocene permanent emplacement of the EAIS include deep-sea oxygen isotope records (Miller et al., 1987) correlated with major sequence boundaries (Haq et al., 1987) and glacimarine sediments deposited on the Antarctic margin (Cape Roberts Science Team, 1999; Roberts et al., 2003). Climatic conditions fluctuated in the early Miocene peaking in warmth at the mid-Miocene Climatic Optimum (~16Ma). A major shift in the stable isotope records at ~14 Ma marks a significant phase of ice growth on Antarctica (Kennett and Shackleton, 1975). This cooling trend continued and by the middle/late Miocene the development of oceanic fronts was well established in the Tasmanian and New Zealand sectors of the Southern Ocean (Exon, Kennett, Malone et al., 2001; Nelson and Cooke, 2001). This dissertation interprets the calcareous nannofossil assemblage data, coupled with robust age models, geochemical and sedimentological data, in order to reconstruct the paleoceanographic conditions in the Tasmanian Gateway during the Miocene. Comparisons between study sites in the Tasmanian Gateway, as well as with other Miocene sections, provides a detailed view of changing paleoceanographic conditions in the Tasmanian region as Australia and Antarctica continued to separate, the ACC and oceanic fronts in the Southern Ocean fully developed and ice volume on Antarctica waxed and waned. A robust calcareous nannofossil biostratigraphy was constructed at ODP Sites 1168, 1170-1172, despite the lack of key marker species from the Discoaster, Sphenolith and Triquetrorhabdulus genera. Diversity was typical of a temperate-water setting, though Site 1168 had higher diversity than the other three sites. Several alternative markers not employed by the Okada and Bukry (1980) zonal scheme were tested and allowed for further subdivision of the stratigraphic column, though not all Miocene calcareous nannofossil zones could be identified. Core disturbance and bioturbation did complicate the interpretation of the sedimentary history, particularly in the upper Miocene and across the Miocene/Pliocene boundary. The robustness of the calcareous nannofossil biostratigraphy was further tested by comparison to biomagnetostraphic data from foraminifers, diatoms, dinocysts, and radiolaria. Second-order bioevents, used to increase the zonal resolution, were compared and found to represent reliable bioevents in the Tasmanian region. Fluctuations in the relative abundances of Coccolithus pelagicus and Reticulofenestra perplexa indicate similar surface water conditions across the study area from ~ 8-12 Ma. Site 1172 is apparently warmer than the other sites beginning at ~ 8 Ma possibly caused by the inception of the proto-East Australia Current. Detailed analysis of calcareous nannofossil assemblage fluctuations across the Oligocene/Miocene boundary (O/M) at Site 1168 support the supposition that the Mi-1 event was a brief glacial associated with only a couple degrees of cooling (Zachos et al, 2001; Roberts et al., 2003) and accompanied by increased productivity (Pollard and DeConto, 2003). Biostratigraphy across the O/M boundary at other Leg 189 Sites indicates increased current activity by the ACC. Analysis of the sediments across the O/M boundary did not reveal any fluctuations at orbital frequencies. The bioturbated and disturbed nature of the cores across the O/M boundary at Site 1168 prevent further analysis at orbital time scales. Sediments recovered by ODP Leg 189 do provide sufficient resolution to create a detailed Southwest Pacific/Southern Ocean temperate-water Miocene calcareous nannofossil biostratigraphy and paleoecological reconstruction. / A Dissertation submitted to the Department of Geological Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Spring Semester, 2007. / March 26, 2007. / Biostratigraphy, ODP Leg 189, Quantitative Biostratigraphy, Oligocene/Miocene Boundary, Antarctic Circumpolar Current / Includes bibliographical references. / Sherwood W. Wise, Jr., Professor Directing Dissertation; Richard Iverson, Outside Committee Member; Neil Lundberg, Committee Member; Yang Wang, Committee Member; Joseph Donoghue, Committee Member.

A method for estimating deep, depth independent current variability is described. The procedure uses XBT derived dynamic heights to remove the near surface signal from altimetric sea surface height (SSH). The difference between SSH and dynamic height is operationally defined as barotropic height (BRT). Currents are obtained from BRT slopes using the geostrophic balance. The method requires the variability below the deepest XBT measurement to be small. Results are restricted to temporal variability, as geoid uncertainties in the SSH data render absolute current estimations impossible. The technique is originally developed for use in the Atlantic Western Boundary Current (WBC). Comprehensive verification of the methodology requires simultaneous SSH, XBT and current meter measurements. There are no available Atlantic data sets that meet these requisites. The alternative is to use synthetic data from the CLIPPER Atlantic model (1=6o resolution). Correlation (r) between estimated and modelled near bottom velocities in WBC areas of interest vary from 0.7 to 0.8. Further tests are conducted with observed data from the Shikoku Basin boundary current in southern Japan, where the method is capable of reproducing the directly measured near bottom current variability (r = 0:6). The procedure is also tested using north Pacific (5o ¡ 55oN) data from the OCCAM model. Correlations between model derived and BRT estimated velocities are around r = 0:7 for the Shikoku Basin northern boundary and for the Pacific WBC. Values reach r = 0:9 in large areas of the basin's interior, specially over smooth topography. The above method is used to generate time series of the barotropic variability in two areas of the Atlantic Western Boundary. One site is located at 38oN, inshore of the Gulf Stream. The other is at 8oS, off the Brazilian coast. Both series are a approximately 6 years long. Empirical Orthogonal Function analysis results conducted on SSH and sea surface temperature data are used to confirm the feasibility of applying the method in the chosen South Atlantic area. Currents are compared to scatterometer derived local along-shore wind stress and basin wide wind stress curl. In both areas, current variability is significantly correlated to basin averaged wind stress curl and and also to local along-shore wind stress. The relationship between currents and wind curl is coherent with the WBC response to interior Sverdrup flow. We propose that local wind stress exerts control over the flow by divergence of the Ekman flow at the coast. In the north, the variability is dominated by interannual oscillations of the wind curl. The effects of the local stress are secondary and have annual frequency. Both wind stress curl and along-shore wind are significantly correlated to the currents on the southern site, but the local effect appears to be the dominant forcing. The main observed results are confirmed by data from a numerical model with 1=6o horizontal resolution. / A Dissertation Submitted to the Department of Oceanography in Partial FulfiLlment of the Requirements for the Degree of Doctor of Philosophy. / Spring Semester, 2004. / November 7, 2003. / TOPEX, Atlantic, Western Boundary, Variability / Includes bibliographical references. / Georges L. Weatherly, Professor Directing Thesis; Steven L. Blumsack, Outside Committee Member; William M. Landing, Committee Member; Doron Nof, Committee Member; James O'Brien, Committee Member; Kevin Speer, Committee Member.

The variations in the sea breeze are examined both diurnally and interannually along the panhandle of Florida during the boreal summer season. A climatology of sea breeze cross sections is calculated eight times daily between the years 1979 and 2001 to examine diurnal differences. The cross sections are created using very high resolution dynamically downscaled analyses from the NCEP-DOE (R2) and the ECMWF ERA-40 for the southeast U.S. The high resolution downscaled product is validated with other independent observations to show fidelity. Results from these diurnal analyses show that the sea breeze and precipitation peak at 4:00 p.m. The interannual variability of the sea breeze is examined with respect to the Atlantic Warm Pool (AWP). Composites consisting of Climate Prediction Center (CPC) precipitation observations are created based on the size of the AWP. These composites show that the strongest low-frequency signal is a negative anomaly along the panhandle. Therefore, model composite cross sections are primarily along the 30.5°N latitude. The cause of the negative anomaly is related to the subtropical high, which undergoes an eastward shift and a decrease in intensity for large AWP years. These changes in the subtropical high lead to a more cyclonic large-scale low-level flow for large AWP years as Sverdrup vorticity balance indicates. This study finds that this synoptic flow pattern will suppress the sea breeze circulation and lessen precipitation amounts over the panhandle region. / 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. / April 28, 2011. / Bermuda High, Atlantic Warm Pool, Sverdrup Vorticity Balance, interannual variations / Includes bibliographical references. / Vasubandhu Misra, Professor Directing Thesis; James J. O’Brien, Professor Co-Directing Thesis; Henry Fuelberg, Committee Member; Mark Bourassa, Committee Member.

Large portions of the world ocean are less productive than they should be based on their nutrient concentrations. Dubbed high-nutrient low-chlorophyll (HNLC) regions, primary productivity in these areas may be limited by any number of factors including high zooplankton grazing rates as well as light and silicon limitation but, in general, iron (Fe) appears to most often be the factor limiting production. With approximately 30% of the world ocean comprised of Fe-limited HNLC waters, it is clear that the input of Fe to these waters, and its subsequent bioavailability, has an important role in stimulating primary productivity and lowering pCO2 possibly moderating the rise of atmospheric CO2 concentrations and therefore could influence the planet's climate. The work described in this dissertation represents an effort to characterize the elemental solubility, including Fe, of marine aerosols. The research was conducted on four oceanographic research cruises in the North Atlantic and Pacific Oceans. In total, over 170 aerosol samples were collected in both total and size-fractionated samples. Precipitation events were sampled when possible to characterize the wet deposition of marine aerosols. The data will constrain estimates of aerosol Fe deposition to HNLC regions and improve models of the global carbon cycle. Elemental solubilities were measured using both seawater and ultrapure deionized water leaching methods under trace metal clean conditions. Leaching of the aerosol samples was conducted using a rapid exposure, small volume technique. Ultrapure deionized water leaches were analyzed directly by high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS), a relatively simple analysis technique. Soluble Fe in seawater leaches was analyzed by HR-ICP-MS following column extraction. Additionally, soluble aerosol Fe(II) was measured on four of the cruises. The sampling and analytical methods will be discussed in this dissertation and the results compared with similar studies of aerosol chemistry. The relationship between seawater and deionized water leaching was investigated to evaluate the applicability of the relatively simple ultrapure water technique to prediction of aerosol solubility in seawater. Elemental solubility behavior was analyzed within the context of a host of potential controlling factors including aerosol acidity, source region, and elemental composition among others. The results from these research cruises suggest that aerosol Fe solubility is relatively consistent globally. The solubility of aerosol Fe in deionized water was calculated to be ~12% and ~9% in filtered surface seawater. Aerosol Fe solubility percentage showed no significant correlation with the concentration of acidic aerosol species. The episodic nature of dust events was apparent from the highly variable measured concentrations of aerosol material and no apparent first order relationship existed between the concentration of crustal aerosol species (i.e. Fe) and their respective concentrations in the surface ocean. A robust relationship was found between the concentrations of the ultrapure deionized water and seawater soluble aerosol Fe and a predictive power law equation was derived. / A Dissertation submitted to the Department of Oceanography in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Summer Semester, 2008. / June 4, 2008. / Aerosol Solubility, Mineral Dust, Atlantic Ocean, Pacific Ocean, Aluminum, Iron / Includes bibliographical references. / William M. Landing, Professor Directing Dissertation; Henry Fuelberg, Outside Committee Member; William Burnett, Committee Member; Joel Kostka, Committee Member; Thorsten Dittmar, Committee Member.

This study addresses the issue of global and regional cloud cover forecasts. Using a suite of global models, the multimodel superensemble forecasts are constructed for total cloud coverage and layered (low, middle, and high) cloud coverage out to 7 days (168 hours). The experiments were conducted on a 1° latitude by 1° longitude spatial grid at a 24 hour temporal resolution. The multimodel superensemble carries a training and a forecast phase. Several training periods were used to determine an optimal training phase. The total period of this study includes October 2006 through February 2007. Clouds from the International Satellite Cloud Climatology Project (ISCCP) were used for training and cloud validations. The metrics for the forecast evaluation include the root mean square errors, spatial correlations, and equitable threat scores. The results show a significant improvement (~25%) of the multimodel superensemble forecasts compared to those from the member models forecasts, as well as their ensemble mean for the global and regional domains. / A Thesis submitted to the Department of Meteorology in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester, 2010. / April 20, 2010. / Cloud Forecasting, Superensemble / Includes bibliographical references. / T. N. Krishnamurti, Professor Co-Directing Thesis; Paul Ruscher, Professor Co-Directing Thesis; Guosheng Liu, Committee Member; Vasu Misra, Committee Member.