Microwave satellite observations provide useful information about atmospheric temperature and water vapor. This insight could be used to improve hurricane forecasting through the assimilation of this data into Numerical Weather Prediction (NWP) models. Brightness temperature observations can be assimilated into NWP model by using a Radiative Transfer Model (RTM) to convert satellite data into conventional meteorological data. To determine if an RTM is useable in an environment such as a hurricane in which hydrometeors are present in large quantities, a comparison of RTM simulated to observed brightness temperatures is necessary. This comparison is a preliminary step in the overall process of data assimilation in the effort to improve hurricane forecasting. The Joint Center for Satellite Data Assimilation (JCSDA) Community Radiative Transfer Model (CRTM) is used to simulate two sets of brightness temperatures for channels 1–6 and 15 of the Advanced Microwave Sounding Unit–A (AMSU–A) within and around Hurricane Ivan. One simulation is run using dropsonde profiles as input and another simulation is run using model data from the Global Forecast System (GFS) to produce two sets of simulated brightness temperature data. The two simulated brightness temperature data sets are compared to actual AMSU–A observations of Hurricane Ivan as well as to each other. Brightness temperatures simulated using the more realistic atmospheric profiles of the dropsonde data compared more favorably with AMSU–A observation than did the GFS simulations, indicating the potential usefulness of the CRTM to produce surface-sensitive AMSU–A channel observations to improved hurricane forecast. / 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, 2012. / June 28, 2012. / AMSU-A, CRTM, dropsonde, Hurricane Ivan, simulated brightness temperatures / Includes bibliographical references. / Xiaolei Zou, Professor Directing Thesis; Mark A. Bourassa, Committee Member; Vasubandhu Misra, Committee Member.

Incorporation of lime amendments is an effective treatment to neutralize acidity, reduce soluble metals, and facilitate plant growth in mine wastes. In general, arsenic (As) solubility increases with increasing pH in As laden mine wastes. However, a number of laboratory and field studies have shown the decrease in As solubility with increase in pH. It has been hypothesized that reduction in soluble As was likely due to presence of amorphous oxides of iron, aluminum and manganese. Further, in experimental studies it has been seen that the total concentration of Fe+Al+Mn was approximately ten times higher in the mine wastes exhibiting decrease in soluble As. There was no correlation suggested with any single element. This study uses PHREEQC for geochemical modeling to investigate the factors and reaction pathways affecting changes in soluble-As concentrations upon liming acidic metalliferous mine wastes. The results indicate that a change in solubility of As upon liming is mainly affected by the presence of amorphous phases of aluminum. Iron and manganese oxides don't play a significant role. Managing contaminated sites (due to infiltration of NAPL) can be expensive, but multiphase models can be an effective tool to predict the subsurface behavior of contaminants and help reduce associated costs. One of the major deficiencies of such models is the prediction of the amount of residual non-aqueous phase liquids (NAPL). In order to accurately predict the behavior of residual NAPL, it is important to understand the formation of residual NAPL. The presence of residual NAPL in the vadose zone has been demonstrated by many researchers, but the conditions under which residual NAPL is formed are poorly understood. Traditionally permeability-saturation-pressure (k-s-p) relations have been used to demonstrate the formation of residual NAPL. Herein, we use electrical conductivity to investigate the process of formation of residual NAPL. Results from the experiments indicate formation of residual NAPL during drainage of NAPL from the system. Further, experimental studies ware undertaken to validate the model presented by Wipfler and van der Zee (2001) with experimental data set in which both oil and water pressure head are determined. Natural soil sample was used instead of Ottawa sand. Ottawa sand has a more uniform grain size than soils so this series of experiments tests the model in a more complex system. Another difference between previous studies and this experiment was the choice of NAPL. Oleic acid, which is a light NAPL was used herein instead of the dense NAPL used by Hofstee et al. (1997). Results from the experiments indicate that the model failed to predict the formation of the residual NAPL under the experimental conditions. / 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, 2011. / August 3, 2011. / Arsenic, conductivity, NAPL, PHREEQc, Vadose Zone / Includes bibliographical references. / Lynn Dudley, Professor Directing Dissertation; Ruby Krishnamurti, University Representative; Ming Ye, Committee Member; James F. Tull, Committee Member.

A new metric for identifying severe tornado (F3+) alleys is presented. Regions are distinguished by average F-scale values with a minimum of 15 severe tornado events within 200km. Five distinct "severe tornado alleys" are described across the United States: 1) the Carolinas, 2) "Dixie Alley," 3) Kansas and Oklahoma, 4) Iowa and Nebraska, and 5) Wisconsin, Illinois, Indiana and Michigan. These regions are evaluated using CFSR global reanalysis data to determine the presence of atmospheric variables relating to tornadogenesis (as described by prior work) in the pre-tornadic environments. Composite CFSR soundings and composite field charts are created for severe tornado events within each region. A robust comparison of pre-tornadic atmospheric conditions among regions is conducted using a Student t-test at 95% confidence.. An evaluation of the Sigtor parameter, a commonly used significant tornado forecast parameter developed by the Storm Prediction Center, is also conducted to identify regional variability. It is found that each region significantly differs at 95% confidence from each other in terms of many atmospheric variables from pre-tornadic environments, with the most significant differences existing between the two more eastern and two mid-western regions. SigTor values and the individual components, are calculated for severe tornado events and for every time-step for every grid-point within each region over a "peak severe tornado season" for U.S. severe tornadoes in order to compare the event cases to a background mean state. It is shown using linear correlations and covariances of the individual terms of the Sigtor parameter to the Sigtor value that not only is there discrepancy in Sigtor values between regions, but the different components of SigTor contribute to the value of Sigtor in different ways between regions. Some regions show background values of Sigtor terms to be favorable for tornadogenesis even when tornadoes have not occurred. Regional biases in presence of atmospheric variables preceding severe tornado events between regions are described. / A Thesis submitted to the Department of Earth, Ocean & Atmospheric Science in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2012. / September 14, 2012. / Alley, Tornado / Includes bibliographical references. / Eric Chassignet, Professor Co-Directing Thesis; Robert Hart, Professor Co-Directing Thesis; Mark Bourassa, Committee Member.

This study evaluates the characteristics and forecast accuracy of the Arctic Oscillation (AO) Index on an intraseasonal time scale. The Arctic Oscillation is a natural pattern of time varying sea-level pressure anomalies that is one of the leading modes of weather variability in the Northern Hemisphere. Sustained shifts in the AO Index can lead to pronounced and sudden changes in weather patterns that can have dramatic economic and social impacts. Previous studies have described characteristics and trends in the AO, but on seasonal and decadal time scales. Focusing on short time scales that can be depicted by Numerical Weather Prediction models, this study describes the AO's influence on surface temperature and the ability of the Global Forecast System (GFS) and Global Ensemble Forecast System (GEFS) numerical models to forecast changes in the AO index. Forecast performance is investigated over a range of atmospheric conditions from 2000-2011. Evaluation metrics include Probability of Detection, False Alarm Rate, and Critical Success Index. In addition, average forecast error is quantified through the use of absolute error calculations. Together, it is presented which evaluation techniques best enhance the AO Index forecast accuracy of the GFS and GEFS models, along with the expected forecast error that the models and methodologies provide. Results conclude that shorter period forecasts that utilize smoothing filters produce the best model performance with the least forecast error. The GFS and GEFS models have enhanced performance when the strength of the shift in the AO Index is sufficiently large (> 2 standard deviations). In addition, during the highly variable winter, forecast performance is largely diminished. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Sciencein partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2012. / August 7, 2012. / Arctic Oscillation, Cold air outbreaks, GFS Forecast / Includes bibliographical references. / Henry E. Fuelberg, Professor Directing Thesis; Robert E. Hart, Committee Member; Philip Sura, Committee Member.

The following study examines the spatiotemporal response of the local scale and large scale environment to tropical cyclone (TC) passage. The research presented here is broken up into three chapters that can be separated into two parts. Given that the analysis of the environmental response to TC passage heavily relies upon the use of atmospheric reanalysis datasets, the first half of this dissertation (Chapter 2) will examine the fidelity of TC intensity, position, and intensity life cycle within five reanalyses to determine what reanalyses can be used for when studying TCs. The results of this analysis show an underestimation of reanalysis TC intensity beyond what can be attributed to the coarse grid resolution of reanalyses. Moreover, the mean life cycle of normalized TC intensity within reanalyses exhibits an underestimation of pre-peak intensification rates as well as a delay in the timing of peak TC intensity relative to the Best Track. Significant discrepancies between reanalysis and Best-Track TC position are noted to exist particularly in regions that are observation deficient. Of the five reanalyses examined, the NCEP Climate Forecast System Reanalysis (CFSR) and JMA 25-yr Japanese Reanalysis (JRA-25) have the most robust representation of TCs particularly within the North Atlantic (NATL) and Western North Pacific (WPAC). The second half of this study examines the local scale (Chapter 3) and large scale (Chapter 4) impacts of WPAC TCs upon their environment using storm-relative composites. On local scales, TCs are found to cool sea surface temperatures (SSTs) for at least a month following TC passage. The feedbacks from the SST cold wake combined with an initial net flux divergence of energy from the column yields a significant cooling and drying of the atmosphere that is strongest in the lower troposphere. Restoration of the environment is eventually achieved through a return of SSTs to climatology and a net flux convergence of potential energy aloft. The large scale response of the environment is primarily associated with an anomalous drying of the lower and middle tropospheric atmospheric environment to the west and southwest of the TC. The drying appears to be caused by upper level convergence resulting from the interaction of the TC outflow with its environment. On the western side of the TC, both the upper level flow from the anticyclone of the Asian monsoon and the increasing inertial stability with latitude due to the meridional gradient of planetary vorticity limit the ventilation to the west of the TC yielding upper level convergence and subsidence. The area of anomalous drying to the southwest is associated with the convergent upper level flow from the right exit region of the anticyclonically curved equatorward outflow jet of the TC. Lastly, the meridional transport of total energy by TCs results in a substantial cross hemispheric export of dry static energy nearly 4000 km southwards as result of the upper level outflow jet of the TC. The meridional dry static energy transports by TCs appear to comprise a substantial portion of the total atmospheric dry static energy transports at the equator during late summer and early fall. In their totality, these results suggest that TCs may significantly impact their environment both on long temporal scales and large spatial scales with potentially significant aggregate climate impacts in the WPAC given the high frequency of TC occurrence. / 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, 2012. / September 27, 2012. / climate, large scale environment, local scale environment, meridional energy transports, reanalysis tropical cyclone representation, tropical cyclones / Includes bibliographical references. / Robert E. Hart, Professor Directing Thesis; William Dewar, University Representative; Robert G. Ellingson, Committee Member; Ming Cai, Committee Member; Allan J. Clarke, Committee Member.

The U.S. Air Force's 45th Weather Squadron (45WS) seeks improved forecasts of lightning cessation at the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) in Florida. The 45WS currently keeps lightning advisories active longer than necessary to ensure the safety of personnel and facilities. This paper describes the use of lightning and dual-polarimetric radar data to develop lightning cessation guidance for east central Florida. Since the dual-polarimetric radar at Patrick Air Force Base in Florida was delayed in becoming operational, we chose central Oklahoma as the domain for the first phase of study because dual-polarimetric data already were available. Pulse thunderstorms in Oklahoma during the warm seasons of 2010 and 2011were chosen to represent the types of warm season (April-July) thunderstorms commonly observed at KSC/CCAFS. Total lightning data were obtained by combining data from the Oklahoma Lightning Mapping Array and the National Lightning Detection Network (NLDN). Storms were tracked using the Warning Decision Support System - Integrated Information software (WDSS-II). The tracking produced time series of radar-derived and lightning parameters. Trends in conventional reflectivity (ZH), as well as various dual-polarimetric parameters at three temperatures crucial to storm electrification (i.e., 0oC, -10oC, -20oC), were analyzed for 30 storms in Oklahoma near the end of their lightning activity. Results from the Oklahoma storms were used to develop numerous potential cessation algorithms. The second phase of study focused on 30 independent storms in Florida during the early 2012 warm season when dual-polarimetric data became available at NWS Melbourne and NWS Tampa. The algorithms developed from the storms in Oklahoma were tested on storms in Florida. Total lightning data for Florida storms were obtained by combining data from the Lightning Detection and Ranging network at CCAFS and the NLDN. WDSS-II again was used extensively. We created a new evaluation methodology that considers the average time of successful cancellations, the average time of premature cancellations, the number of hits, and the average timing of each event. Premature cancellations are weighed most heavily (negatively) because they are the most dangerous situation. An overall score was calculated for each of the 39 cessation algorithms. Results reveal that the best performing cessation algorithm in Florida utilizes ZH > 40 dBZ and the presence of graupel (PID = 12 from WDSS-II) at -10oC. One waits 10 min after these thresholds are no longer met before ending an advisory. This procedure did not prematurely end a lightning advisory for any of the 30 Florida storms. The average cancellation time after lightning actually occurred was 12.5 min. This is a considerable time savings over the 45WS' most conservative wait-time of 30 min, providing substantial economic benefits without sacrificing safety. This study shows the importance and utility of using graupel to improve lightning cessation guidance for storms near KSC/CCAFS. However, the results are tentative, and the procedure must be tested and refined on a much larger dataset. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Sciencein partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2012. / August 9, 2012. / Includes bibliographical references. / Henry E. Fuelberg, Professor Directing Thesis; Sharon Nicholson, Committee Member; Philip Sura, Committee Member.

Deep-sea meiofauna along the continental rise off the west coast of North America are nearly unstudied. To begin to remedy this situation, I sampled each of four regions (off Oregon and off northern, central, and southern California) for meiofaunal major taxa (i.e., nematodes, copepods, ostracods, and kinorhynchs) and for environmental factors in the band between 2700 and 3700 m depth. The abundances in each region fit well with those from previous reports from the Pacific. For each meiofaunal major taxon, abundance was greatest off central California. Food, as measured by chlorophyll a concentration in the sediment, was the best explanatory variable except for the ostracods, for which abundance was best explained by the proportion of mud in the sediment. Unexpectedly, only copepod abundance decreased significantly with depth in the 1000-m wide band studied. My assessment of multivariate similarity revealed that the Bray-Curtis similarity in meiofaunal major taxa between samples was no less than 89% despite as much as 1500 km of separation, so the basic composition of the meiofauna along the rise in this depth band varies little. Despite the overall similarity, I found groups composed of samples that were not significantly different from each other but were significantly different from all other samples. The groups were formed primarily on differences among samples in abundance and were best explained by variations in the amount of food in the sediment. / 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, 2012. / October 4, 2012. / Abundance, Deep sea, Meiofauna, Pacific / Includes bibliographical references. / David Thistle, Professor Directing Thesis; William M. Landing, Committee Member; Ian MacDonald, Committee Member.

Indications of climatic warming are expected to be greatest over high latitudes and high altitudes, the regions where the cyrosphere is present. Mountain glaciers, in particular, can be an early detector for man-induced climate change, and it is a representative indicator for the surface energy balance for remote polar or high altitude locations. Previous research has shown the surface energy budget over a snow surface can either over-estimate or severely under-estimate the radiation processes. This is due to the complexities of the snow surface including high but variable albedo, low thermal conductivity, low roughness length, and maintaining the ability to store water for long periods of time. For this study, the surface energy balance over Barrow, Alaska will be modeled using the O/FSU 1-D Coupled Atmosphere-Plant-Soils Model and compared against observations over a snow pack for twenty-seven events from 2004 though 2010. Different formulations for albedo over snow surfaces will be used to determine optimal radiation budget and boundary layer structure calculations. Results from this study have implications on climate research and future land surface models. / 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, 2012. / June 12, 2012. / snow surface, surface energy balance / Includes bibliographical references. / Paul Ruscher, Professor Directing Thesis; Alejandro Gallard, Committee Member; Guosheng Liu, Committee Member; Sharon Nicholson, Committee Member.

Anthropogenic emissions are transported both locally and globally. Depending on the magnitude of the transport, the emissions can have varying impacts on air quality and atmospheric chemistry. Transport occurs most efficiently if emissions are lofted to the middle or upper troposphere. Major mechanisms producing vertical transport are the warm conveyor belt (WCB) of middle latitude cyclones and deep convection that may be embedded within. Global chemical transport models appear to adequately simulate large-scale WCB transport, but the convection is parameterized which does not capture the fine-scale transport due to deep convection. This study uses the WRF-Chem chemical transport model to simulate a middle latitude cyclone in East Asia at three different horizontal resolutions (45, 15, and 5 km grid spacing). The cyclone contains a typical WCB with an embedded squall line and passes through an area of large surface CO concentrations. We use model output from WRF-Chem to compare differences between the large-scale transport of the WCB (the 45 km simulation) and the smaller-scale transport due to convection (the 15 km simulation). Forward trajectories are calculated from WRF-Chem output using HYSPLIT. At 45 km grid spacing, the WCB exhibits gradual ascent, lofting surface CO to 6 - 7 km. Upon reaching the warm front, the WCB and associated CO turn eastward and diffuse over the Pacific Ocean. Convective transport at 5 km resolution with explicitly resolved convection occurs very rapidly, with surface CO lofted to altitudes greater than 10 km in 1 h or less. As the surface CO reaches the tropopause it spreads horizontally both eastward and westward with little diffusion. The coarse 45 km spaced domain also contained a short wave trough and an extensive area of convection, not related to the cyclone, that were responsible for slowly lifting considerable CO to the upper troposphere. We also compute CO mass fluxes to compare the differences in vertical transport due to the different grid spacings. In the domain with explicit convection, upward CO fluxes exceed 100,000 t when the squall line is at peak intensity, while fluxes from the two coarser resolutions are an order of magnitude smaller. Specific areas of interest were defined to examine the role of convective transport within the entire 5 km domain. Convection encompasses only a small portion of the domain, but is responsible for ~ 40% of the upward CO transport. These results indicate that fine-scale resolution is critically important when examining the transport of surface emissions in areas of deep convection. / 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, 2012. / October 24, 2012. / Model, WRF / Includes bibliographical references. / Henry Fuelberg, Professor Directing Thesis; Guosheng Liu, Committee Member; Robert Hart, Committee Member.

Wildfires have a great impact throughout the atmosphere, particularly in the surface and boundary layers. The magnitude of heat flux and turbulence generated by the spread of these fires is relatively large and has scarcely been quantifiable. Six experimental burns were conducted in short grass fuels at an agricultural and range field station in Georgia to examine the production of turbulence and other thermal processes in the surface layer in the presence of these small, yet intense wind-driven fires. Burn plots were prepared and arrays of instrument-equipped towers were created in different configurations depending on the type of fire to be set. This study focuses on two of them for which comprehensive atmospheric surface layer data were collected: two head fires burning simultaneously and a fire with a fuel reduction treatment. The generation of turbulent kinetic energy and kinematic heat flux is examined and quantified, and changes in the ambient flow are found upon the passage of these fires, along with quick returns to ambient conditions in the surface layer. Also, comparisons were made between the results found in this study and the results found in previous experimental burns of a similar nature. Possible applications are examined, including the determination of plume boundary thresholds and characteristics and the development of a potential plume detection algorithm. / A Thesis submitted to the Department of Earth, Ocean, and Atmospheric Sciencein partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester, 2012. / September 4, 2012. / fire behavior, grassland, meteorology, surface layer, turbulence / Includes bibliographical references. / Paul H. Ruscher, Professor Directing Thesis; Robert G. Ellingson, Committee Member; Robert E. Hart, Committee Member.