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Title: 4D-Var Assimilation of Toms Ozone Measurements for the Prediction of Mid-Latitude Winter Storms.
Creator: Jang, Kun-Il, Zou, Xiaolei, Navon, Ionel M., Barcilon, Albert I., Krishnamurti, T. N., O'Brien, James J., Department of Earth, Ocean and Atmospheric Sciences, Florida State...
Show moreJang, Kun-Il, Zou, Xiaolei, Navon, Ionel M., Barcilon, Albert I., Krishnamurti, T. N., O'Brien, James J., Department of Earth, Ocean and Atmospheric Sciences, Florida State University
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Abstract/Description: In this study, two kinds of methodology are proposed for incorporating total column zone data from the Total Ozone Mapping Spectrometer (TOMS) into initial conditions of a mesoscale prediction model. The first methodology is based on the strong linear correlation between vertical mean potential vorticity (MPV) and TOMS ozone (O3). The second methodology assimilates the TOMS ozone observations directly by adding the ozone transport equation into the MM5 model and its adjoint. The three...
Show moreIn this study, two kinds of methodology are proposed for incorporating total column zone data from the Total Ozone Mapping Spectrometer (TOMS) into initial conditions of a mesoscale prediction model. The first methodology is based on the strong linear correlation between vertical mean potential vorticity (MPV) and TOMS ozone (O3). The second methodology assimilates the TOMS ozone observations directly by adding the ozone transport equation into the MM5 model and its adjoint. The three-dimensional ozone initial condition for the transport equation is estimated from the observed ozone. The proposed first approach of ozone assimilation is applied to two case studies. The first case is the notable Washington D. C. snow storm (to be called DCSTORM) that occurred between 24 - 25 January 2000 along the East Coast of the United States. The second case is an Atlantic Ocean winter storm that was observed between 14-16 February 1997 (to be called AOSTORM). It is found that adjustments in model initial conditions assimilating TOMS ozone-only data are confined to the upper levels and produced almost no impact to the prediction of the storm development. However, when TOMS ozone data are used together with radiosonde observations, a more rapid deepening of the sea level pressure of the simulated storm is observed than with radiosonde-only observations. The predicted motion of the DCSTORM is also altered, with a track closer to the coast. On the contrary, assimilation of only TOMS ozone data produces non-negligible adjustment of wind and temperature fields at all levels in the AOSTORM case. When compared with dropsonde observations, TOMS ozone data improves model forecasts of both temperature and moisture fields. Adjoint sensitivity studies indicate that the significant impact of TOMS ozone on cyclone prediction is expected if large TOMS ozone anomalies appear in a region where model error is grow.
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Date Issued: 2004
Identifier: FSU_migr_etd-3626
Format: Thesis

Title: Abundance of Bottlenose Dolphins (Tursiops Truncatus) in the Big Bend of Florida, St. Vincent Sound to Alligator Harbor.
Creator: Tyson, Reny Blue, Nowacek, Douglas, Dewar, William, Wells, Randy, Chanton, Jeffrey, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Mark-recapture surveys implementing photographic identification techniques were used to estimate the abundance of bottlenose dolphins in an area of the Big Bend of Florida, stretching from St. Vincent Sound to Alligator Harbor, in the summer of 2007 and winter of 2008. The current population size of individuals in this region is unknown as the most recent abundance estimates were calculated based on aerial surveys conducted in 1993. Recent large scale mortality events, together with an...
Show moreMark-recapture surveys implementing photographic identification techniques were used to estimate the abundance of bottlenose dolphins in an area of the Big Bend of Florida, stretching from St. Vincent Sound to Alligator Harbor, in the summer of 2007 and winter of 2008. The current population size of individuals in this region is unknown as the most recent abundance estimates were calculated based on aerial surveys conducted in 1993. Recent large scale mortality events, together with an increasing potential for human impacts in this area, warrant an updated and increased understanding of the abundance and stock structure of dolphins in this region. Because the region is large and recent work here suggests that at least two distinct communities exist in these waters, the region was divided into the two areas in which these communities appear to reside (St. Vincent Sound/Apalachicola Bay and St. George Sound/Alligator Harbor) and independent estimates of abundance were calculated for each area and each season. Closed-population models in the program CAPTURE were used to derive the estimates of abundance and the assumptions underlying each model were examined. The estimates calculated from the models selected as being the most appropriate for each data set were similar for each survey area for each season: in the St. Vincent Sound/Apalachicola Bay survey area 182 ± 58 animals inhabited the survey area in the summer and 178 ± 77 animals in the winter; in the St. George Sound/Alligator Harbor survey area 365 ± 164 animals inhabited the survey area in the summer and 359 ± 87 animals in the winter. Results from this study also provided further evidence that at least two communities reside in these waters as only 2.4% of animals captured during the study were captured in both survey areas. If indeed two communities exist in these waters, it appears that site-fidelity and/or residence patterns of individuals may differ between them; in the St. Vincent Sound/Apalachicola Bay survey area 49.6% of the total animals captured were captured more than once and 29.6% were captured both seasons, while in the St. George Sound/Alligator Harbor survey area 35.3% were captured more than once and 13.8% of animals were captured both seasons. In addition, it appears that the St. George Sound/Alligator Harbor survey area supports a greater number of transient animals than the St. Vincent Sound/Apalachicola survey area (46.1% of distinctive animals were seen only once versus 29.9% respectively). This may be due in part to this survey area being more accessible to the open waters of the Gulf of Mexico than the St. Vincent Sound/Apalachicola Bay survey area, which is more protected by barrier islands. The results provided here can be used by the National Marine Fisheries Service to aid in their stock-assessment process and help in the management of the animals in this region.
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Date Issued: 2008
Identifier: FSU_migr_etd-0323
Format: Thesis

Title: The Accuracy of the National Hurricane Center's United States Tropical Cyclone Landfall Forecasts in the Atlantic Basin (2004–2012).
Creator: Keclik, Alexandra, Department of Earth, Ocean and Atmospheric Sciences
Abstract/Description: This study examined the position, timing, and intensity of each National Hurricane Center's (NHC) Official Forecasts (OFCL) for Atlantic tropical storms and hurricanes that made landfall in the United States from 2004 to 2012. During that time period, one hundred and fifty tropical cyclones developed in the Atlantic basin. Thirty-two of the cyclones made landfall in the United States as tropical storms or hurricanes. Accurate predictions of the location, timing, and intensity of tropical...
Show moreThis study examined the position, timing, and intensity of each National Hurricane Center's (NHC) Official Forecasts (OFCL) for Atlantic tropical storms and hurricanes that made landfall in the United States from 2004 to 2012. During that time period, one hundred and fifty tropical cyclones developed in the Atlantic basin. Thirty-two of the cyclones made landfall in the United States as tropical storms or hurricanes. Accurate predictions of the location, timing, and intensity of tropical cyclone landfalls are important, so that people in a storm's track can prepare adequately for heavy to catastrophic wind, rain, and storm surge. The errors of each of the OFCL for Atlantic tropical storms and hurricanes that made landfall in the United States during 2004–2012 are acquired from the Best Track data set. The ELTOPO1 landmask is used to find the forecasted landfall point using sequential locations from the OFCL offshore and onshore points of each forecast. The great circle distance between the forecasted and actual landfall constitutes the location error. The official landfall time is subtracted from the forecasted landfall time to find the timing error, and the official landfall wind speed is subtracted from the closest to onshore wind speed to find intensity error. There is a trend of decreasing error in location, timing, and intensity forecasting with decreasing lead time. An improvement in tropical cyclone landfall forecasting is found from comparing the 2004–2012 Atlantic landfall forecast errors to those in a study of 1976-2000 forecasts.
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Date Issued: 2014
Identifier: FSU_migr_uhm-0324
Format: Thesis

Title: Accurate and Precise Determination of Low Concentration Iron, Arsenic, Selenium, Cadmium, and Other Trace Elements in Natural Samples by Octopole Collision/Reaction Cell (CRC) Equipped Quadrupole-ICP-Ms.
Creator: Dial, Angela, Landing, William M., Salters, Vincent J. M., Humayun, Munir, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: An improved method for accurate and precise determination of trace quantity dissolved metals and metalloids in natural samples by Octopole Collision/Reaction Cell (CRC) equipped Quadrupole-Inductively Coupled Plasma-Mass Spectrometry (Agilent® 7500cs) is reported. Our method is optimized for rapid analyses of small volume samples (~250 µL) in a variety of matrices containing HNO3 and/or HCl. The present study focuses on elements with ICP-MS plasma- and/or matrix based interferences, in...
Show moreAn improved method for accurate and precise determination of trace quantity dissolved metals and metalloids in natural samples by Octopole Collision/Reaction Cell (CRC) equipped Quadrupole-Inductively Coupled Plasma-Mass Spectrometry (Agilent® 7500cs) is reported. Our method is optimized for rapid analyses of small volume samples (~250 µL) in a variety of matrices containing HNO3 and/or HCl. The present study focuses on elements with ICP-MS plasma- and/or matrix based interferences, in particular 56Fe (40Ar16O+), 75As (40Ar35Cl+), 78Se (40Ar38Ar+), and 111Cd (95Mo16O+). We demonstrate efficient elimination of these polyatomic interferences via the use of CRC in Reaction Mode (RM; H2 gas) and in Collision-Reaction Mode (CRM; He gas). In addition, the efficiency of the instrument was evaluated under both hot plasma (RF power 1500 Watts) and cool plasma (600 W) conditions. The present method is optimized to analyze elements with large mass spectrometric interferences at sub parts per billion level concentrations in a variety of natural samples and matrix compositions. We report an average external precision of ≤ ~10% for minor (≤ 10 µg∙L-1) elements measured in a 1:100 dilution of NIST 1643e under two different plasma conditions and CRC operational modes. Our measured concentration values for elements like Fe (99.6 µg/L), Mg (8020 µg/L), Co (26.99 µg/L), Ni (62.54 µg/L), Cd (7.68 µg/L), Sb (59.6 µg/L), and Pb (19.82 µg/L) with a large dynamic spread in concentrations in NIST 1643e are within ±12% to ±2% of the accepted / published values.
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Date Issued: 2013
Identifier: FSU_migr_etd-7353
Format: Thesis

Title: Acoustic Ecology of the Bottlenose Dolphin (Tursiops Truncatus) in the Big Bend Region of Florida.
Creator: Rycyk, Athena, Nowacek, Douglas, Mann, David, Laurent, Louis St., Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: I examined the acoustic ecology of coastal bottlenose dolphins (Tursiops truncatus) in the Big Bend region of Florida and compared it to other populations of dolphins found in similar habitats. This region is one of the most acoustically pristine coastal environments in Florida, marked by little human activity. Historically this region's dolphin population has not been studied, leaving a gap in our knowledge of these animals. Acoustic recordings were collected as part of photo-identification...
Show moreI examined the acoustic ecology of coastal bottlenose dolphins (Tursiops truncatus) in the Big Bend region of Florida and compared it to other populations of dolphins found in similar habitats. This region is one of the most acoustically pristine coastal environments in Florida, marked by little human activity. Historically this region's dolphin population has not been studied, leaving a gap in our knowledge of these animals. Acoustic recordings were collected as part of photo-identification and habitat-use surveys, and then categorized into fall, winter, spring, and summer seasons. Whistle rates were highest in spring, even when normalized for group size. Echolocation rates were not different between seasons over both years, but individual years had differences. Interestingly, burst pulse sounds and pops rarely occurred. Bottlenose dolphins are not the only source of noise in their marine habitat, so to understand the acoustic environment of these animals, human- and fish-produced sounds were also considered. Remote autonomous acoustic recorders were deployed at eight sites in the Big Bend region and each location was found to have a unique soundscape with respect to dolphin, fish, snapping shrimp, and human-produced sound. Toadfish (Opsanus beta), sea catfish (Arius felis), and silver perch (Bairdiella chrysoura) were the only identifiable fish species to produce sound and caused notable increases in sound levels at low frequencies where they vocalized. There were twelve unidentifiable biological sounds; all exhibit properties of fish or invertebrate produced sounds. Locations exhibited different temporal peaks in fish sound production. Overall, human-produced noise was uncommon and only found in the form of boat noise, but when present it greatly increased sound levels, especially in low frequencies. Dolphin vocalizations were not found at all locations, however, the lack of dolphin vocalizations does not necessarily mean that dolphins were not present in these regions. This study confirmed that the region is relatively acoustically pristine.
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Date Issued: 2007
Identifier: FSU_migr_etd-1958
Format: Thesis

Title: Aerosol Iron Solubility: Observations from the Atlantic and Pacific Oceans.
Creator: Buck, Clifton Stryker, Landing, William M., Fuelberg, Henry, Burnett, William, Kostka, Joel, Dittmar, Thorsten, Department of Earth, Ocean and Atmospheric Sciences, Florida...
Show moreBuck, Clifton Stryker, Landing, William M., Fuelberg, Henry, Burnett, William, Kostka, Joel, Dittmar, Thorsten, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
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Abstract/Description: 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...
Show moreLarge 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.
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Date Issued: 2008
Identifier: FSU_migr_etd-2885
Format: Thesis

Title: African Easterly Waves and Their Relationship to Rainfall on a Daily Timescale.
Creator: Baum, Jeffrey D., Nicholson, Sharon E., Krishnamurti, T. N., Kim, Kwang-Yul, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: African Easterly Waves (AEWs) are mesoscale synoptic features that form in West Africa and propagate westward. The relationship of AEWs to rainfall in the region has been examined in previous studies but no scientific consensus has been reached. This relationship, however, has been found to be complex and to involve numerous feedback mechanisms such as the African Easterly Jet (AEJ) fluctuations. Other mechanisms like latent heat release and the temperature gradient at the surface between the...
Show moreAfrican Easterly Waves (AEWs) are mesoscale synoptic features that form in West Africa and propagate westward. The relationship of AEWs to rainfall in the region has been examined in previous studies but no scientific consensus has been reached. This relationship, however, has been found to be complex and to involve numerous feedback mechanisms such as the African Easterly Jet (AEJ) fluctuations. Other mechanisms like latent heat release and the temperature gradient at the surface between the dry Sahara Desert and the moist maritime region along the Gulf of Guinea also play a role in the relationship between rainfall and AEWs. This study will investigate the relationship of AEWs to rainfall through objective analysis of the waves and an EOF analysis of daily rainfall over a prescribed region. Two classification schemes along with statistical techniques were used to investigate the spatiotemporal variability of the relationship between African Easterly Waves (AEWs) and the rainfall over West Africa. Two varying methods were used because of the highly subjective manner of tracking AEWs. This study was limited to four wet years (1958 â1961) and four dry years (1982-1985) during the summer months of June, July, August and September. The first technique was a new three-step method designed by Dr. A. Fink that makes use of 700mb and 850mb streamline plots and band-pass filtered meridional wind data. The second method uses the vertical structure of the band-pass filtered meridional wind to identify wave passage. The methods were compared and contrasted with one another, and both were shown to be adequate for tracking AEWs. However, for examining the relationship of rainfall with AEWs the second method appropriately named the Vertical Profile Method (VPM) was found to be preferable. Using the VPM the difference between wave characteristics and rainfall variability were examined on a daily timescale. This involved creating daily rainfall datasets for four different quadrants over the Sahel and relating any changes in rainfall activity to the AEWs as they both propagated across the quadrants. The differences in AEW and rainfall characteristics were examined by making comparisons within two distinct time-frame perspectives. The first perspective examined differences between wet and dry years and the second perspective examined differences between the 1st two months (June-July) and the last two months (August-September). For each category the strength of the waves, number of waves, location of the north and south regime, rainfall distribution and rainfall amounts were compared. During the wet years (1958 -1961) the number of waves that propagated across West Africa averaged 59 waves per year using the Vertical Profile Method (VPM) and 49 using the Andreas Fink Method (AFM). The number of AEWs tracked during the dry years (1982-1985) averaged about 63 with the VPM and 54 with the AFM. The difference in the average number of AEWs between the methods was probably a result of the limitations of each method. More waves in the dry years supports previous conclusions that stronger but less frequent AEWs occur in wet years and weaker but more frequent AEWs occur in the dry years. Tracking of the AEWs also allowed for the separation of the AEWs into two distinct wave regimes north and south of the African Easterly Jet (AEJ). Throughout all eight years the separation became apparent as the summer progressed with the separation reaching a maximum. This coincides with the fluctuations in AEJ intensity, which also has a maximum in the month of August. Rainfall within the tracked AEWs was found to be bimodal with the region of maximum northerly flow containing the most rainfall. This region is ahead of the trough and is typically associated with squall line convective activity. The maximum region was the same for both wet and dry years and also for the two month season comparison. An EOF analysis of daily rainfall was completed for 1958 (wet year) and 1983 (dry year) to determine if any relationship to AEWs could be identified in the rainfall time series. The resulting eigenvalues show the influence of topography along the Guinea coast with positive values: however, no discernable link to AEWs was present. The power spectrum of the first two principle components did identify a significant peak at the same period associated with AEWs. This power spectrum analysis demonstrated that rainfall is linked to AEWs, but a more detailed dynamical investigation is needed.
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Date Issued: 2006
Identifier: FSU_migr_etd-1138
Format: Thesis

Title: Algorithms for Advanced Tropical Cyclone Visualization.
Creator: Winterbottom, Henry R., Zou, Xiaolei, Erlebacher, Gordon, Bourassa, Mark A., Liu, Gousheng, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: With the events of recent years - especially in the Atlantic tropical basin, the need for additional forecast tools to aid in tropical cyclone (TC) prediction and understanding is apparent. A suite of algorithms to be used for 3-D TC visualization are presented. Utilizing the assets of the Amira visualization software, we present methods which constitute a real-time visualization routine of TC genesis, mesoscale, and TC centered features derived from the The Florida State University (FSU)...
Show moreWith the events of recent years - especially in the Atlantic tropical basin, the need for additional forecast tools to aid in tropical cyclone (TC) prediction and understanding is apparent. A suite of algorithms to be used for 3-D TC visualization are presented. Utilizing the assets of the Amira visualization software, we present methods which constitute a real-time visualization routine of TC genesis, mesoscale, and TC centered features derived from the The Florida State University (FSU) adaptation of the Pennsylvania State University (PSU) and National Center for Atmospheric Research (NCAR) Fifth Generation Mesoscale Model (MM5). However, the algorithms we develop are generic in that they can be applied to any gridded output from a forecast model. A method for the removal TC vorticity fields allowing an approximation of the environmental steering levels is also developed. The development and use of an adaptive wavenumber refinement filter (AWRF) has proven to outperform various alternative methods for TC vortex removal and thus the preservation of the environmental flow. Case study inter-comparisons are performed and illustrate that the AWRF provides the smallest mean track errors in future forecast position compared to those determined by the model's use of minimum sea level pressure (SLP) and vorticity maxima algorithm for TC center location. Discussions are also provided suggesting areas of needed improvement within the algorithm as illustrated by the case studies presented.
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Date Issued: 2006
Identifier: FSU_migr_etd-0929
Format: Thesis

Title: Altitude Effect on the Stable Isotope Chemistry of Tooth Enamel from Modern Herbivores in Tibet: Implications for Paleoclimate and Paleoelevation Reconstructions.
Creator: Kromhout, Elizabeth, Wang, Yang, Odom, A. Leroy, Parker, William, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: A total of 123 bulk and serial enamel samples were obtained from modern goats, horses and yaks from southern Tibet for C and O isotope analysis. The δ13C and δ18O values of tooth enamel were compared with the δ13C values of local vegetation and the δ18O values of local waters to examine the relationship between the isotopic composition of modern herbivores and their environment. The δ13C values of enamel samples from horses range from -11.2‰ to -13.9‰ with an average δ13C value of -12.7 ± 1.0...
Show moreA total of 123 bulk and serial enamel samples were obtained from modern goats, horses and yaks from southern Tibet for C and O isotope analysis. The δ13C and δ18O values of tooth enamel were compared with the δ13C values of local vegetation and the δ18O values of local waters to examine the relationship between the isotopic composition of modern herbivores and their environment. The δ13C values of enamel samples from horses range from -11.2‰ to -13.9‰ with an average δ13C value of -12.7 ± 1.0‰ (n=13). The δ13C values of yak tooth enamel range from -7.3‰ to -14.2‰, averaging -10.1±1.4‰ (n=84). The goat teeth have δ13C values ranging from -7.8‰ to -12.1‰, with a mean of -10.2 ± 1.2‰ (n=26). These enamel δ13C values indicate that these modern herbivores were feeding predominantly on C3 plants, consistent with the current dominance of C3 vegetation in the region. Some of the samples have δ13C values between -7.3 and -9‰. Although these higher δ13C values could suggest consumption of some C4 plants by the animals, the lack of significant seasonal δ13C variations within individual teeth indicates that these higher enamel δ13C values are more likely due to consumption of C3 plants experiencing water stress and/or some CAM plants. This suggests that the "cut-off" δ13C value for a pure C3 diet can be as high as -8‰ in water-stressed environments. The δ13C variations within and between species primarily reflect the variations in the δ13C values of the C3 plant foodstuffs consumed by the animals. The δ13C values of tooth enamel do not show a trend with increasing elevation. Oxygen isotopic compositions of tooth enamel varied widely within and between species. In contrast to the small intra-tooth δ13C variations within individual teeth, serial enamel samples display large intra-tooth δ18O variations, reflecting seasonal variations in the oxygen isotopic composition of meteoric water. The mean δ18O values of tooth enamel from goats showed a correlation with water δ18O values, suggesting that the δ18O of tooth enamel can be used as a proxy for the δ18O of meteoric water. Unfortunately, the oxygen isotopic compositions of water and tooth enamel do not show a clear trend with increasing elevation in the study area, suggesting that quantitative reconstruction of paleoelevation in this region using reconstructed δ18O values of paleo-meteoric water from fossil tooth enamel or other O-bearing minerals may not be warranted. For a given elevation/environment, horses have the lowest enamel δ18O values while goats display the highest enamel δ18O values among the three species studied. The large inter-species δ18O variations are due to differences in physiology and diet/drinking behavior of the animals. This confirms the importance of species-specific studies when interpreting δ18O data of fossil mammalian teeth in a stratigraphic sequence as a record of paleoclimate changes.
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Date Issued: 2007
Identifier: FSU_migr_etd-2868
Format: Thesis

Title: Analysis and Evolution of Balance in Unstable Barotropic Jets.
Creator: Smith, Travis Allen, Cunningham, Philip, Barcilon, Albert I., Krishnamurti, T. N., Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: The nature of balance in the atmosphere is of central importance to the dynamics of both the troposphere and the stratosphere, and unbalanced motions such as inertia-gravity waves play a significant role in many aspects of atmospheric behavior. In light of the importance of upper-tropospheric jets for the generation of inertia-gravity waves in the atmosphere, this study examines the evolution of unstable barotropic jets to assess the nature and evolution of balance in these features. This...
Show moreThe nature of balance in the atmosphere is of central importance to the dynamics of both the troposphere and the stratosphere, and unbalanced motions such as inertia-gravity waves play a significant role in many aspects of atmospheric behavior. In light of the importance of upper-tropospheric jets for the generation of inertia-gravity waves in the atmosphere, this study examines the evolution of unstable barotropic jets to assess the nature and evolution of balance in these features. This issue is explored using the simplest non-trivial dynamical framework in which balanced and unbalanced flows can coexist, namely the one-layer shallow water equations. In this study, numerical simulations of initially balanced zonal barotropic jets on an f plane are investigated for evidence of the breakdown of balance and the generation of inertia-gravity waves during the life cycles of the instabilities to these jets. In these simulations, the parameters of the basic-state jet (i.e., jet width and speed) are varied systematically in an attempt to elucidate the dependence of balance on the structure and dynamical evolution of the instability. The presence of unbalanced flow, either in numerical simulations or in atmospheric data, is typically inferred via various quantities that provide indirect measures of imbalance, such as the existence of strong ageostrophy, large Rossby and/or Lagrangian Rossby numbers, and large values of horizontal divergence and its material derivative. Along with evaluating these parameters in each simulation, a potential vorticity inversion method is employed to obtain the structure of balanced and unbalanced fields within each simulation. The diagnostic calculations are then compared to the potential vorticity inversion results. Contrasts and comparisons are presented for each of the simulations shown in this study. The simulations consist of an unstable barotropic wave ranging from small (i.e., O(10-1)) Rossby and Froude number to large (i.e., O(1)) Rossby and Froude number. For strong jets, neither the Rossby number nor the Froude number is small compared to unity therefore the applicability of traditional scale analysis is unclear (e.g. Haltiner and Williams, 1980) (i.e., the balance condition is no longer valid and a breakdown of balance should occur). In contrast, the results of the diagnostic calculations and potential vorticity inversions reveal that nonlinear balance is essentially valid for this particular jet profile, even though the Rossby and Froude numbers are O(1) for the strong barotropic jet. Significant inertia-gravity wave structures were not found in any of the cases shown here, which is consistent with the results obtained by several other investigators in their integrations of the shallow-water equations.
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Date Issued: 2004
Identifier: FSU_migr_etd-1666
Format: Thesis

Title: An Analysis of Climate Feedback Contributions to the Land/Sea Warming Contrast.
Creator: Albert, Oriene S., Cai, Ming, Sura, Phillip, Liu, Guosheng, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: The land/sea warming contrast being greater than unity is a well-known phenomenon in response to anthropogenic radiative forcing. The land/sea surface warming asymmetry is essentially a result of the differing surface and boundary layer properties over the land and ocean as well as the differing cloud feedbacks. In this study, we analyze the surface temperature response over the land and ocean, using the NCAR CCSM4, to a transient 1% yr-1 CO2 increase at the time of the doubling. The...
Show moreThe land/sea warming contrast being greater than unity is a well-known phenomenon in response to anthropogenic radiative forcing. The land/sea surface warming asymmetry is essentially a result of the differing surface and boundary layer properties over the land and ocean as well as the differing cloud feedbacks. In this study, we analyze the surface temperature response over the land and ocean, using the NCAR CCSM4, to a transient 1% yr-1 CO2 increase at the time of the doubling. The contributions of the external forcing (CO2) alone and various feedbacks are diagnosed using the Climate Feedback Response Analysis Method (CFRAM). This study found that the external forcing warms the land and ocean surfaces approximately the same, which suggests that the feedbacks are responsible for the warming contrast. Furthermore, this analysis confirms that the principal contributor to the above-unity land-to-sea warming ratio is the evaporation feedback; however, the results also indicate that the sensible heat flux feedback, which favors a greater warming for the ocean, has the largest land/sea warming difference. Consequently, the findings uniquely highlight the importance of other feedbacks in establishing the above-unity land-to-sea warming ratio. Specifically, the cloud and ocean dynamics/heat storage feedbacks are key contributors to the maintenance of the land/sea warming asymmetry. The results of this study provide a more holistic understanding of the climate feedbacks and their significance to the land and ocean temperature responses, when the climate is forced.
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Date Issued: 2014
Identifier: FSU_migr_etd-8929
Format: Thesis

Title: Analysis of Convective Transport of Biomass Burning Emissions in Southeast Asia.
Creator: Ahern, Kyle, Department of Earth, Ocean and Atmospheric Sciences
Abstract/Description: Biomass burning and anthropogenic emissions affect the composition of the atmosphere, thereby impacting global climate and health. Deep convective processes can loft emissions from the boundary layer into the upper troposphere or lower stratosphere (UTLS). Strong upper-level winds can potentially transport the emissions over long distances. This study focused on the deep convective transport of biomass burning emissions near the Strait of Malacca during summer. The Weather Research and...
Show moreBiomass burning and anthropogenic emissions affect the composition of the atmosphere, thereby impacting global climate and health. Deep convective processes can loft emissions from the boundary layer into the upper troposphere or lower stratosphere (UTLS). Strong upper-level winds can potentially transport the emissions over long distances. This study focused on the deep convective transport of biomass burning emissions near the Strait of Malacca during summer. The Weather Research and Forecasting (WRF) and Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT_4) models were used to investigate deep convection and the transport of emissions from fires in the region. Fire data from the Moderate-resolution Imaging Spectroradiometer (MODIS) sensors onboard the Aqua and Terra satellites provided locations of fire emissions. These fire datasets were obtained from the University of Maryland's Fire Information for Resource Management System (FIRMS). To investigate the deep convective processes thoroughly, this study used high resolution modeling (4 km grid spacing) to resolve the convection explicitly. Explicit resolution allows the thunderstorms to be simulated more realistically than would parameterization, thus making it ideal for this research. Results showed that deep convection occurring in the Strait of Malacca is driven primarily by diurnal heating patterns and the region's topography. Convection in the region is frequent and scattered, but follows a cyclic diurnal pattern: convection over land during daytime and over the Strait during nighttime. When emissions from fires encounter areas of deep convection, they are quickly lofted to the UTLS where winds then transport them elsewhere.
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Date Issued: 2013
Identifier: FSU_migr_uhm-0216
Format: Thesis

Title: An Analysis of Cyclogenesis for Mid-Latitude and Tropical Storms Using the Petterssen-Sutcliffe Development Equation.
Creator: Hession, William M., Ruscher, Paul, Fuelberg, Henry, Krishnamurti, T. N., Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: In this study, the Petterssen-Sutcliffe development equation is used to examine cyclogenesis. In the past, several other methods have been used to study cyclogenesis and calculate vertical motion, such as the kinematic and adiabatic methods, quasi-geostrophic theory as well as the approaches derived from them. However, there is little documentation on the application of the historical Petterssen-Sutcliffe method, and hence the motivation for this study. The forcing terms of the Petterssen...
Show moreIn this study, the Petterssen-Sutcliffe development equation is used to examine cyclogenesis. In the past, several other methods have been used to study cyclogenesis and calculate vertical motion, such as the kinematic and adiabatic methods, quasi-geostrophic theory as well as the approaches derived from them. However, there is little documentation on the application of the historical Petterssen-Sutcliffe method, and hence the motivation for this study. The forcing terms of the Petterssen-Sutcliffe development equation are calculated using GEMPAK software. These forcing terms include vorticity advection, temperature advection, stability, and diabatic heating. Two mid-latitude storms and two tropical systems were analyzed to see if this method could recognize cyclogenesis in both baroclinic and barotropic environments. The first mid-latitude storm occurred in late January 2000. It formed off the coast of the Carolinas and traveled up the East Coast over the Atlantic Ocean. The second storm spent its life cycle over land in the Mid-Atlantic and New England regions during March 1999. Both tropical systems originated in the Gulf of Mexico: Hurricane Earl (1998) and Hurricane Gordon (2000). This method of analysis was shown to have general success in identifying cyclogenesis of mid-latitude cyclones and somewhat limited success with tropical storms. It is hoped that this method will benefit both educational and operational environments where students and forecasters can use this additional analysis to supplement their understanding of the atmosphere.
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Date Issued: 2004
Identifier: FSU_migr_etd-4069
Format: Thesis

Title: Analysis of Extreme Events in the PUMA Model.
Creator: Christophersen, Jonathan, Sura, Philip, Ellingson, Robert, Ahlquist, Jon, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: This study investigates the changes in skewness and kurtosis of five atmospheric variables due to a change in the forcing of a primitive equation global circulation model. First, the average, variance, skewness, and kurtosis are calculated at each grid point of a 100 year time series from the Portable University Model of the Atmosphere (PUMA) model. Global and zonally averaged plots of the first four statistical moments are shown for each variable, which we denote as our control run. The same...
Show moreThis study investigates the changes in skewness and kurtosis of five atmospheric variables due to a change in the forcing of a primitive equation global circulation model. First, the average, variance, skewness, and kurtosis are calculated at each grid point of a 100 year time series from the Portable University Model of the Atmosphere (PUMA) model. Global and zonally averaged plots of the first four statistical moments are shown for each variable, which we denote as our control run. The same technique was then done on the same variables under different temperature forcings: an idealized "global warming" environment and "global cooling" environment. Finally, the average, variance, skewness, and kurtosis fields from both the warming and cooling runs were subtracted from the control run to demonstrate the differences in the statical fields. From this we determine that the primitive equations do in fact contribute to the non-Gaussianity seen in the real atmosphere. Also there appears to be a connection to strong non-Gaussianinity due to a stronger equator-pole temperature gradient.
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Date Issued: 2013
Identifier: FSU_migr_etd-8539
Format: Thesis

Title: An Analysis of Global Atmospheric Non-Gaussian Extreme Events.
Creator: Perron, Maxime, Sura, Philip, Ahlquist, Jon, Hart, Robert, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Statistics of extreme events in weather and climate (e.g. rare floods or strong wind storms) are commonly based on the assumption of Gaussian statistics. Sixty-two years of National Centers for Environmental Prediction / National Center for Atmospheric Research (NCEP / NCAR) Reanalysis I data and thirty-one years of National Centers for Environmental Prediction / Department of Energy (NCEP / DOE) Reanalysis II data are analyzed to determine if this assumption is true. The mean and variance of...
Show moreStatistics of extreme events in weather and climate (e.g. rare floods or strong wind storms) are commonly based on the assumption of Gaussian statistics. Sixty-two years of National Centers for Environmental Prediction / National Center for Atmospheric Research (NCEP / NCAR) Reanalysis I data and thirty-one years of National Centers for Environmental Prediction / Department of Energy (NCEP / DOE) Reanalysis II data are analyzed to determine if this assumption is true. The mean and variance of several atmospheric variables are calculated. Furthermore, the higher statistical moments — skewness and kurtosis — are calculated for geopotential height, relative vorticity, and the meridional and zonal wind components. Zonal averages of these higher statistical moments are also analyzed. It is found that statistically significant deviations from Gaussianity are found for every variable in the atmosphere on the synoptic to global scales. This empirical analysis is linked to particular atmospheric phenomena such as tropical cyclones, sudden stratospheric warming events, and the concept of rectifica- tion. In essence, there are fundamental forcing asymmetries in the atmospheric equa- tions of motion that lead to the existence of non-Gaussian distributions. Additionally, the relationship between skewness and kurtosis and the existence of power-law tails in non-Gaussian systems is examined.
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Date Issued: 2010
Identifier: FSU_migr_etd-2018
Format: Thesis

Title: An Analysis of Temporal and Spatial Variations of Surface Albedo over Africa.
Creator: States, Julie, Nicholson, Sharon E., Ahlquist, Jon E., Liu, Guosheng, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Surface albedo is defined as the ratio of the reflected to the incident solar radiation on the earth's surface. Some general circulation model simulations indicate that an increase in albedo due to desertification and deforestation may lead to reduction in precipitation and evapotranspiration. The monthly mean of an earlier surface albedo dataset and MODIS are used to examine the surface albedo spatial and temporal variations of Africa. In order to study surface albedo temporal variations the...
Show moreSurface albedo is defined as the ratio of the reflected to the incident solar radiation on the earth's surface. Some general circulation model simulations indicate that an increase in albedo due to desertification and deforestation may lead to reduction in precipitation and evapotranspiration. The monthly mean of an earlier surface albedo dataset and MODIS are used to examine the surface albedo spatial and temporal variations of Africa. In order to study surface albedo temporal variations the African continent is divided into three regions: northern, equatorial and southern. Even though every month is analyzed, only the four months of February, April, July and November are discussed. In the northern region both the earlier dataset and MODIS the surface albedo showed the largest annual range in surface albedo in the semi-arid and arid areas. It is in these areas where the Meteosat surface albedo values were highest. While MODIS also showed a similar annual range in these areas, however this range was over a much smaller area. The spatial variations in surface albedo in the northern region depict the geographical features of the region. Also in the semi-arid and arid areas of the northern region is where the two datasets most differed. The largest differences between the datasets occur in February, which is during the dry season. It is in these areas where the largest surface albedo values were found and these areas are near or are west of major dust sources. In the southern region as was the case in the northern region the semi-arid and arid areas had the largest annual ranges. In the southern region the actual surface albedo for the semi-arid and arid region are lower than the surface albedo in the northern region for the same areas. The two datasets differ the most in the semi-arid and arid areas. To further understand the temporal and spatial variations of surface albedo, two land cover classification schemes were examined. MODIS uses the International Geosphere-Biosphere Programme 17-land cover scheme. A second land cover dataset was created from White/UNESCO vegetation map to be used with the earlier surface albedo dataset. In some areas the maximum albedo occur in the wet season while in other areas maximum albedo occur in the dry season. In the areas where maximum albedo occurs in the wet season, vegetation tended to be the major factor in determining surface albedo. In Charney's classic 1975 paper he theorized that a reduction in vegetation would lead to an increase in surface albedo, which in turn would lead to a reduction in precipitation. In this for a majority of the vegetation groups minima in surface albedo and NDVI occur at the same time of year. These findings do not support Charney's theory that a reduction in vegetation will lead to an increase in surface albedo. Surface albedo may be influenced by an increase in reflective surfaces. One of the objectives of understanding the spatial and temporal variations in surface albedo is to compare model calculated surface albedo to satellite derived surface albedo. A Comparison of Biosphere-Atmosphere Transfer Scheme, Land Surface Model to Advanced Very High Resolution Radiometer lead to the parameterized albedo in the Community Land Model version 2 to be adjusted. As satellite instrumentation improves so must the land surface process of general circulation models. This study shows that the parameterized surface albedo in Community Land Model version 2 still may not correctly represent the semi-arid and arid regions of Africa. The parameterized vegetation and soil albedo values are still too low.
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Date Issued: 2005
Identifier: FSU_migr_etd-1574
Format: Thesis

Title: An Analysis of the Extratropical Flow Response to Recurving Atlantic Tropical Cyclones.
Creator: Brannan, Allison, Department of Earth, Ocean and Atmospheric Sciences
Abstract/Description: There is a significant frequency of Atlantic tropical cyclones that complete extratropical transition and recurve in the mid-latitudes. Using a climatological approach, this study will analyze the extratropical flow response to recurving Atlantic tropical cyclones and compare the results to those from the Western North Pacific, as examined by Archambault et al. (2013). This investigation includes 54 recurving Atlantic tropical cyclones occurring between 2007 and 2013. The extratropical flow...
Show moreThere is a significant frequency of Atlantic tropical cyclones that complete extratropical transition and recurve in the mid-latitudes. Using a climatological approach, this study will analyze the extratropical flow response to recurving Atlantic tropical cyclones and compare the results to those from the Western North Pacific, as examined by Archambault et al. (2013). This investigation includes 54 recurving Atlantic tropical cyclones occurring between 2007 and 2013. The extratropical flow response will be quantified using potential vorticity. Characteristics of tropical cyclones, the extratropical jet stream, and the dynamical "phasing" of their interaction will be examined to determine the features that lead to significantly amplified extratropical flow. Results show the extratropical flow to be insensitive to the wind speed, latitude, and month of recurvature. However, there is an association between low mean sea level pressure and a larger amplification of flow. Finally, tropical cyclones recurving on the east side of the nearest trough are shown to have "favorable phasing," which yields amplification of the extratropical flow.
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Date Issued: 2015
Identifier: FSU_migr_uhm-0538
Format: Thesis

Title: An Analysis of the Impacts of Western North Pacific Tropical Cyclones on Their Local and Large Scale Environment.
Creator: Schenkel, Benjamin A. (Benjamin Alan), Hart, Robert E., Dewar, William, Ellingson, Robert G., Cai, Ming, Clarke, Allan J., Department of Earth, Ocean and Atmospheric Sciences,...
Show moreSchenkel, Benjamin A. (Benjamin Alan), Hart, Robert E., Dewar, William, Ellingson, Robert G., Cai, Ming, Clarke, Allan J., Department of Earth, Ocean and Atmospheric Sciences, Florida State University
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Abstract/Description: 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...
Show moreThe 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.
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Date Issued: 2012
Identifier: FSU_migr_etd-5430
Format: Thesis

Title: Anatomy of Oligocene-Miocene Debris Flows and Slumps from Demerara Rise: Implications for Margin Destruction.
Creator: Ingram, Wesley, Wise, Sherwood W., Arnold, Anthony J., Froelich, Philip, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Calcareous nannofossils and stable isotopes were analyzed to determine the timing and causes of extensive Miocene debris flows and Oligocene slumps recovered by Ocean Drilling Program (ODP), cruise Leg 207 to Demerara Rise along French Guiana and Suriname. Five modes of emplacement are considered for the Oligocene and Miocene failures. These hypotheses include canyon incision and infilling, clathrate dissociation, sediment loading, current activity, and seismic triggering. Calcareous...
Show moreCalcareous nannofossils and stable isotopes were analyzed to determine the timing and causes of extensive Miocene debris flows and Oligocene slumps recovered by Ocean Drilling Program (ODP), cruise Leg 207 to Demerara Rise along French Guiana and Suriname. Five modes of emplacement are considered for the Oligocene and Miocene failures. These hypotheses include canyon incision and infilling, clathrate dissociation, sediment loading, current activity, and seismic triggering. Calcareous nannofossil ages of the Miocene debris flows at Hole 1261A down to 351 mbsf indicate that the debris flow(s) were emplaced within the time period of Subzone NN11b (7.2 – 5.5 Ma). Hence, nannofossil biostratigraphy provides a time interval of 1.7 m.y. Compared to previous drilling along the New Jersey Transect these results indicate the mass wasted deposits here are fundamentally different, i.e., not the result of canyon incision and infilling. Instead, this study suggests that the emplacement of the Miocene debris flows resulted from high mass accumulation rates combined with a seismic trigger. Paleocurrent reorganization and/or sea-level changes best account for the Oligocene slumps.
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Date Issued: 2005
Identifier: FSU_migr_etd-3869
Format: Thesis

Title: Annual to Interannual Barotropic Variability in the Atlantic Western Boundary.
Creator: Montengro, Alvaro, Weatherly, Georges L., Blumsack, Steven L., Landing, William M., Nof, Doron, O'Brien, James, Speer, Kevin, Department of Earth, Ocean and Atmospheric Sciences...
Show moreMontengro, Alvaro, Weatherly, Georges L., Blumsack, Steven L., Landing, William M., Nof, Doron, O'Brien, James, Speer, Kevin, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
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Abstract/Description: 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...
Show moreA 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.
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Date Issued: 2004
Identifier: FSU_migr_etd-2333
Format: Thesis

Title: Application of Organic Geochemical Proxies in the Environment.
Creator: Das, Oindrila, Wang, Yang, Chanton, Jeff, Odom, A. Leroy, Kish, Stephen A., Hsieh, Yuch Ping, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: This dissertation research has used stable and radioactive isotope techniques to address several important issues in paleoclimate and paleoecoloical research which includes the reliability of using stable carbon isotope composition of black carbon or charcoal to reconstruct paleovegetation, the utility of organic geochemical proxies as paleo-storm indicators, and the reliability of radiocarbon dating of both organic and inorganic carbon in coastal dune lake sediments. The results are below: ...
Show moreThis dissertation research has used stable and radioactive isotope techniques to address several important issues in paleoclimate and paleoecoloical research which includes the reliability of using stable carbon isotope composition of black carbon or charcoal to reconstruct paleovegetation, the utility of organic geochemical proxies as paleo-storm indicators, and the reliability of radiocarbon dating of both organic and inorganic carbon in coastal dune lake sediments. The results are below: (i) C4 and C3 grasses were subjected to burning in the laboratory to determine whether there was any significant fractionation of carbon (C) isotopes between plant material and corresponding ash and smoke produced from burning. The results show that smoke produced from C4 grasses is generally depleted in 13C relative to the original plant, but the magnitude of the 13C depletion varies with species from less than 0.5 / to a maximum of 7.2 /. Ash derived from C4 grasses, on the other hand, is either depleted (by 0.1 to 3.5 /) or slightly enriched (<1 >/) in 13C relative to the original grass depending on species. In contrast, both smoke and ash produced from C3 plants do not show any significant deviation in ï¤13C from that of the original plant material. Our data also show that the C isotope fractionation between ash and smoke and the original plant material depends not only on plant species and plant type but also on burning temperature. The weight percentage of C in ash and smoke decreases with increasing burning time in the temperature range 400-7000C. Multi-elemental thermo analysis of ash, smoke and original plant material reveal distinctly different chemical characteristics for these materials. Ash is preferentially enriched in compounds with higher thermal stability whereas smoke contains a wide spectrum of compounds with different stability in comparison with the original plant material. C4 grass appears to be more thermally stable than C3 grass. These results have important implications for paleoecological or ecological studies based on 13C signatures of black C or charcoal. (ii) Late Holocene paleoclimate records from coastal regions are important for understanding long-term variability of hurricane activity. Here we present a nearly 4000-year record of severe storms and environmental changes based on organic geochemical proxies (OGPs) preserved in sediment cores from two coastal dune lakes in northwest Florida. The OGPs data show that there are significant variations in δ13C, δ15N, C%, N% and C/N with depth, reflecting changes in lake environment that affected the processes delivering water/sediment to the lake as well as biological productivity within the lake. Analysis of modern organic materials in the lakes and their surrounding areas shows that the major sources of sedimentary organic matter in the lake are aquatic and terrestrial C3 vegetation. C4 grasses, although can be found in the mostly forest watershed, do not contribute significantly to the sedimentary organic matter in the lake. Thus, the positive C and N isotopic shifts, concurrent with negative shifts in C/N ratios, most likely indicate shifts to a marine-like environment in coastal lakes following the influx of marine water/nutrients and marine biota associated with major storm events. Some of these isotopic shifts observed in the sediment cores correspond to visible sand layers presumably representing overwash deposits associated with severe storm events. Radiocarbon dating of bulk sediment organic matter, wood fragments and shells indicates that the sediment in these cores was deposited over the last 3-4 thousand years. Assuming the radiocarbon dates are reliable, Eastern Lake data suggest that the recurrence interval of severe storms (i.e., large enough to cause seawater flooding of the lakes) is approximately 83 years over the last 2900 years, whereas Western lake data suggest an average recurrence interval of 87 years in the past 3900 years. iii) Our preliminary radiocarbon data from two coastal lakes in NW Florida show that DOM in these lakes has modern 14C signatures while POM is depleted in 14C compared to the DOM. The positive ï14C values of DOM are due to the influence of the "bomb" radiocarbon and indicate that DOM in these lakes during the time of our sampling were originated primarily from organic matter photosynthesized in recent decades. The variable radiocarbon ages of POM and DOM in the lakes at different times reflect the heterogeneity in the sources of organic carbon. Our data also reveal inconsistencies in radiocarbon ages derived from bulk sediment organic matter. Radiocarbon ages of sediment organic matter are relatively older than contemporaneous shell or wood samples found in the sediment cores. Because bulk sediment organic matter is a mixture of organic matter from both aquatic and terrestrial sources, influx of old or dead organic carbon from different old organic matter deposits or soils due to erosion by runoff is most likely the cause of radiocarbon deficiencies in the lake sediments, resulting in radiocarbon ages of bulk sediment organic matter being older and erroneous. On the other hand, our limited 14C dates on shells seem to be more or less consistent with the dates of wood fragments in the same core, suggesting that these carbonate shells may have been formed in 14C equilibrium with the atmosphere and therefore may serve a reliable and useful substrate for radiocarbon dating when wood fragments cannot be found. Analysis of additional samples is required to investigate and quantify the reservoir effect on organic and inorganic carbon in coastal lakes.
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Date Issued: 2012
Identifier: FSU_migr_etd-6905
Format: Thesis

Title: Applications of Calcareous Nannofossils and Stable Isotopes to Cenozoic Paleoceanography: Examples from the Eastern Equatorial Pacific, Western Equatorial Atlantic and Southern Indian Oceans.
Creator: Jiang, Shijun, Wise, Sherwood W., Iverson, Richard L., Arnold, Anthony J., Donoghue, Joseph F., Wang, Yang, Department of Earth, Ocean and Atmospheric Sciences, Florida State...
Show moreJiang, Shijun, Wise, Sherwood W., Iverson, Richard L., Arnold, Anthony J., Donoghue, Joseph F., Wang, Yang, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
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Abstract/Description: This dissertation is a collection of five calcareous nannofossil and one stable isotope studies on materials from Ocean Drilling Program (ODP) Legs 183 (Site 1135), 206 (Site 1256), and 207 (Site 1259) that target two important paleoceanographic events: 1) the middle/late Miocene carbonate crash, and 2) the Paleocene/Eocene Thermal Maximum (PETM). Site 1256 nannofossil biostratigraphy in Chapter 1 refined the author's shore-based shipboard Quaternary-middle-Miocene nannofossil biostratigraphy...
Show moreThis dissertation is a collection of five calcareous nannofossil and one stable isotope studies on materials from Ocean Drilling Program (ODP) Legs 183 (Site 1135), 206 (Site 1256), and 207 (Site 1259) that target two important paleoceanographic events: 1) the middle/late Miocene carbonate crash, and 2) the Paleocene/Eocene Thermal Maximum (PETM). Site 1256 nannofossil biostratigraphy in Chapter 1 refined the author's shore-based shipboard Quaternary-middle-Miocene nannofossil biostratigraphy with 16 zones/combined zones recognized based on 28 nannofossil datums. This chapter provides a chronologic framework for the age calibration of the first occurrence (7.18 Ma) and last occurrence (6.32 Ma) of Reticulofenestra rotaria, calculation of linear sedimentation rates, age determination of basalt basement (~14.5 Ma), and the recognition of the "carbonate crash" paleoceanographic event at the middle/late Miocene boundary. Reworked nannofossils and lithologic changes also allow a reading of a three-episode redepositional history (4.7, 8.3, and 10.7 Ma, respectively) in the eastern Pacific. The detailed examination of the Site 1256 material also yielded well-preserved Discoaster stellulus, for which only the distal view had been depicted in the original description. In Chapter 2, a redescription and re-illustration of both sides of this asterolith is provided. This should prevent misidentification of specimens in proximal view, thereby raising its potential application for middle-late Miocene biostratigraphy. Based on the above age model, in Chapter 3 stable oxygen and carbon isotopes were used for the first time to explore the late/middle Miocene "carbonate crash". This carbonate transition is a widespread (eastern and central equatorial Pacific, Indian, South Atlantic, and the Caribbean), sharp decrease in carbonate mass-accumulation rates, which has previously been considered only a dissolution event. The positive correlation (R2 = 0.75) between d13C and CaCO3 mass accumulation rates during 5-14 Ma at ODP Site 1256 clearly demonstrates that carbonate accumulation is mainly biologically controlled. The coincidence of the carbonate crash with negative excursions in d13C and d18O values suggests a causative mechanism related to surface-water productivity, as a result of surface-water warming and reduced upwelling. Based on these observations, one could speculate that the major middle/late Miocene sea-level drop may have caused the complete closure of the Indonesian Seaway, resulting in a piling-up of surface warm water in the west Pacific. The eastward spread of this nutrient-poor water then would have warmed sea-surface temperatures and reduced upwelling in the central and eastern Pacific, thereby creating a prolonged "El Nino" scenario and reducing biological productivity of phytoplankton. The reduction in carbonate supply to the deep waters consequently caused a rapid shoaling of the carbonate compensation depth, thereby triggering the carbonate crash. The PETM was a catastrophic, rapid greenhouse-forced global warming event ~55 m.y. ago that triggered an abrupt turnover in ocean chemistry and circulation as well as biota. Chapter 4 represents a quantitative study of the response of nannoplankton to the PETM at Demerara Rise, equatorial Atlantic (Site 1259). Toweius, Fasciculithus, and Chiasmolithus sharply decrease at the onset of the PETM, whereas Chiasmolithus, Markalius cf. M. apertus, and Neochiasmolithus thrive immediately after the event, which also signals the successive first appearances of Discoaster araneus, Rhomboaster, and Tribrachiatus. Two main environmental factors were extracted by correspondence analysis of relative abundance data. The time series of the two factors shows that during the PETM, 1) environmental stress (most likely from changes in seawater pH) increased and may well have also induced the evolution of ephemeral nannofossil "excursion taxa"; and 2) surface-water productivity increased at this site presumably due to higher runoff from continental areas. The local phytoplankton opportunist, Markalius cf. M. apertus, is described as a new species in Chapter 5, which will be published under the name Coccolithus bownii. Results presented in Chapter 6 from Site 1135 on the Kerguelen Plateau, Southern Ocean suggest that nannoplankton responded differently to the PETM at southern high latitudes. The onset of the carbon isotope excursion occurs within an 18-cm interval (instead of 1-2 cm as observed in most deep-sea sections) before the peak is reached, displaying a linear mixing curve. This indicates that the release of light carbon was a gradual, single injection, instead of multiple pulses as suggested in previous work, and that this sequence is highly expanded as a result of high sedimentation rates at this relatively shallow oceanic site. This is evidenced by the high numbers of dissolution-susceptible holococcoliths (Zygrhablithus bijugatus) preserved throughout the sequence. Although r- and K-selected specialists exponentially increase in abundance at the onset, Chiasmolithus abruptly drops but then rapidly recovers, whereas Discoaster and Fasciculithus show opposite trends, indicating that in high latitudes, surface-water oligotrophy prevailed at the carbon isotope excursion (CIE) onset but mesotrophic conditions dominated the CIE recovery. These observations confirm previous results from ODP Site 690 on Maud Rise. The intensive dissolution of susceptible holococcoliths and the poor preservation of the assemblages are believed to have been caused by the effects of corrosion caused by the methane release. The different responses of nannoplankton to the PETM and the contrasts evident in previous work from the open ocean vs the continental margins further demonstrate that the response to the PETM can be influenced by local differences in geologic setting and oceanographic conditions.
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Date Issued: 2007
Identifier: FSU_migr_etd-3512
Format: Thesis

Title: Are Subterranean Estuaries a Source of Chromophoric Dissolved Organic Matter (CDOM) to the Coastal Ocean?: A Case Study in the Northern Gulf of Mexico.
Creator: Suryaputra, I Gusti Ngurah Agung, Huettel, Markus, Dittmar, Thorsten, Burnett, William, Chanton, Jeffrey, Department of Earth, Ocean and Atmospheric Sciences, Florida State...
Show moreSuryaputra, I Gusti Ngurah Agung, Huettel, Markus, Dittmar, Thorsten, Burnett, William, Chanton, Jeffrey, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
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Abstract/Description: Submarine groundwater discharge (SGD) is a major pathway for nutrient transport in coastal marine systems. There are indications that SGD may also release large amounts of dissolved organic matter (DOM) to the coastal ocean and thus impact coastal ecosystem functioning. DOM is usually quantified as dissolved organic carbon (DOC), which requires discrete sampling. Therefore, detailed time series on tidally-driven SGD cannot easily be obtained for DOC. The chromophoric component of DOM (CDOM)...
Show moreSubmarine groundwater discharge (SGD) is a major pathway for nutrient transport in coastal marine systems. There are indications that SGD may also release large amounts of dissolved organic matter (DOM) to the coastal ocean and thus impact coastal ecosystem functioning. DOM is usually quantified as dissolved organic carbon (DOC), which requires discrete sampling. Therefore, detailed time series on tidally-driven SGD cannot easily be obtained for DOC. The chromophoric component of DOM (CDOM) can be monitored via specific fluorescence in high temporal resolution and in situ. Here we hypothesize that SGD is a significant source of CDOM to the coastal ocean, impacting optical properties and biogeochemical cycles of coastal waters. In this context we also evaluated the possibility of using CDOM as a proxy for DOC in a subterranean estuary. To test our hypothesis, a case study was performed in a shallow bay in the Northern Gulf of Mexico. CDOM was continuously monitored in situ for approximately three weeks in a groundwater well on a beach and 300 m offshore in the adjacent bay. The radon isotope 222Rn was also continuously measured as a conservative tracer for submarine groundwater in the bay. Discrete samples for DOC analysis and associated variables were collected to cover one tidal cycle (15 hours). In a simple SGD model, CDOM concentrations in the bay were predicted by multiplying 222Rn concentrations in the bay (as a measure for SGD) with CDOM concentrations in the well (as the groundwater endmember). This was done for each hour during the entire sampling period. If a lag-time of one hour between groundwater and bay was considered, the predicted CDOM significantly correlated (p<0.01) with the measured CDOM in the bay. Independent statistical tests, including chlorophyll a, salinity and water level data, confirm this finding and demonstrate that CDOM in the bay is mainly driven by freshwater SGD. More detailed analysis of the time series data show that short-term time series of 24 hours or less can lead to erroneous results in estimating SGD. CDOM and DOC significantly correlated for the groundwater endmember, and CDOM could thus be transformed into DOC concentrations. It was estimated that at least 0.6 Mega-mole DOC are delivered to the entire Gulf Coast of Florida in a day via SGD which is similar in order of magnitude as riverine fluxes.
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Date Issued: 2009
Identifier: FSU_migr_etd-1496
Format: Thesis

Title: Assessing Storm Severity Using Lightning and Radar Information.
Creator: Rudlosky, Scott D., Fuelberg, Henry E., Stallins, J. Anthony, Clayson, Carol Ann, Hart, Robert E., Liu, Guosheng, Department of Earth, Ocean and Atmospheric Sciences, Florida...
Show moreRudlosky, Scott D., Fuelberg, Henry E., Stallins, J. Anthony, Clayson, Carol Ann, Hart, Robert E., Liu, Guosheng, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
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Abstract/Description: 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...
Show moreLightning 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.
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Date Issued: 2011
Identifier: FSU_migr_etd-1929
Format: Thesis

Title: Assessing the Potential Impact of Gifts Data to Severe Convective Precipitation Prediction.
Creator: Yorsaner, Mark Evan, Zou, Xiaolei, Hart, Robert, Ruscher, Paul, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: A two-phase study of the potential impact of Geosynchronous Imaging Fourier Transfer Spectrometer (GIFTS) radiance data to the prediction of strong convective events was developed. In the first phase of the project, a statistical analysis of six runs of the Fifth Generation Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5), version 3, was performed. These runs incorporate different size domains, numbers of vertical levels, numbers of nesting domains,...
Show moreA two-phase study of the potential impact of Geosynchronous Imaging Fourier Transfer Spectrometer (GIFTS) radiance data to the prediction of strong convective events was developed. In the first phase of the project, a statistical analysis of six runs of the Fifth Generation Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model (MM5), version 3, was performed. These runs incorporate different size domains, numbers of vertical levels, numbers of nesting domains, and physical schemes. Using high-resolution National Center for Environmental Prediction (NCEP) Stage IV precipitation estimates, mesonet data, and radar reflectivity, it was determined that of all runs, one was chosen as being most appropriate for simulating GIFTS radiance. This run incorporates the simple ice microphysical scheme, the Grell cumulus scheme, the Blackadar planetary boundary layer scheme, and a simple atmospheric radiation scheme. Furthermore, this run was nested, with the mother domain (12-km resolution) of size 163 x 127 x 54 and the nested domain (4-km resolution) of size 103 x 127 x 54. In the second phase of the project, two sensitivity studies were carried out. In the first sensitivity study, the sensitivity of simulated GIFTS radiance to temperature and water vapor were examined. The 14 most sensitive channels within the GIFTS spectral range, out of 3,073, were chosen for further analysis. Through an analysis of an MM5 grid point that had relatively minimal cloud cover, it was determined that the most sensitive atmospheric layers at eight channels are in the lower troposphere (temperature) and lower to mid-troposphere (water vapor). At the other six, the most sensitive region is in the mid- to upper troposphere. The layers of maximum sensitivity are consistent with peaks of the weighting functions of these channels. The second sensitivity study examined the sensitivity of convective precipitation forecasts to the initial conditions of temperature and water vapor. The purpose of this study was to "bridge" the results of the first sensitivity study to the MM5 quantitative precipitation forecast (QPF) results. It was found that the most sensitive region is over the Central Plains of the United States and that the convective QPF is most sensitive to both water vapor content and temperature in the low-levels of the troposphere. Furthermore, temperature is deemed more sensitive to convective QPFs than water vapor. The results from these sensitivity tests, when linked together, demonstrate that GIFTS radiance at the eight wavenumbers most sensitive in the lower troposphere may be more effective to improve QPF than higher wavenumber radiance and that temperature in the Central Plains is the key meteorological variable to which the convective QPF is most sensitive. In a future four-dimensional variational data assimilation (4D-Var) study, simulated and real atmospheric observations from various sources will be assimilated into the MM5, with the GIFTS model representing the observation operator. Through this current study, a better sense of the utility of data from GIFTS to the forecasting of convective precipitation is ascertained, which would help streamline the 4D-Var study.
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Date Issued: 2005
Identifier: FSU_migr_etd-0856
Format: Thesis

Title: Assessing Uncertainty in Simulated Atmospheric Transport and Dispersion Using a WRF-3DVAR Cycling Multiphysics Ensemble.
Creator: Riggi, Antonio Giuseppe, Fuelberg, Henry, Hart, Robert, Ahlquist, Jon, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: This study examines the degree of uncertainty that occurs in atmospheric transport and dispersion (ATD) modeling due to using different parameterizations of physical processes such as shortwave and longwave radiative processes, precipitation formation, and atmosphere-surface interactions. An ensemble approach is taken to examine how this one aspect of meteorological model uncertainty affects subsequent ATD simulations. Differences in these Weather Research and Forecasting (WRF) physics...
Show moreThis study examines the degree of uncertainty that occurs in atmospheric transport and dispersion (ATD) modeling due to using different parameterizations of physical processes such as shortwave and longwave radiative processes, precipitation formation, and atmosphere-surface interactions. An ensemble approach is taken to examine how this one aspect of meteorological model uncertainty affects subsequent ATD simulations. Differences in these Weather Research and Forecasting (WRF) physics configuration strategies are investigated through their effects on offline HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) ATD simulations of three October 2010 tracer releases conducted in a region of complex terrain. The WRF model consists of three nested domains, with the innermost (highest resolution) domain having a horizontal grid spacing of 2 km. A twenty member ensemble of input meteorological data for the ATD simulations is generated through 6 h WRF cycling runs that employ three-dimensional variational data assimilation (3DVAR) on the outer two domains, but not on the innermost domain. Each of the twenty members uses a different combination of WRF physics parameterizations. Characteristics of several aspects of the 3DVAR system are presented. Single observation tests reveal increments that reflect physical balances imposed during the data assimilation process. Consistent RMS error reduction by 3DVAR improves the quality of information provided at the lateral boundaries of the innermost domain (∆x = 2 km). RMS errors of 10-meteruandvwinds are generally reduced by 0.4-0.5 m s−1, and RMS errors of 2-meter temperature are reduced by 1.5-3 K throughout the cycling runs. Considerable spread in PBL height, a key ATD variable, is produced in the innermost domain, especially during the daytime hours (σ = 141-200 m). HYSPLIT dispersion simulations using the ensemble members show a wide spread of ground-level concentration fields, as well as varying degrees of vertical transport, that are a consequence of the choice of model physics configurations, with plume areas sometimes varying by over 1000 km2. Verification metrics quantitatively illustrate the concentrations at the ground truth field study measurement stations that can be obtained by varying the model physics parameterizations. Ensemble-based probabilities provide a useful method of describing the likelihood that a given concentration will be exceeded.
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Date Issued: 2013
Identifier: FSU_migr_etd-8628
Format: Thesis

Title: Assessment of Groundwater Discharge to Lake Barco via Radon Tracing.
Creator: Stringer, Christina Elaine, Burnett, William C., Chanton, Jeffrey P., Sturges, Wilton, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Groundwater-surface water interactions in lakes have been gaining attention in recent years as scientists have recognized the potential significance that groundwater has as a source of nutrients and contaminants to aquatic ecosystems. Such interactions need to be understood in order for us to protect important ecosystems and quantify nutrient loading into lakes. This project set out to test the idea that good estimates could be made of groundwater inputs into Florida lakes using a simple...
Show moreGroundwater-surface water interactions in lakes have been gaining attention in recent years as scientists have recognized the potential significance that groundwater has as a source of nutrients and contaminants to aquatic ecosystems. Such interactions need to be understood in order for us to protect important ecosystems and quantify nutrient loading into lakes. This project set out to test the idea that good estimates could be made of groundwater inputs into Florida lakes using a simple geochemical tracer technique. We hypothesize that a relatively small number of measurements would be sufficient to provide a reasonably good (a factor of 2) estimate of groundwater discharge. Naturally occurring 222Rn makes an ideal tracer because it exists in enriched concentrations in groundwater relative to surface water. We used Lake Barco, a small seepage lake in the Katherine Ordway Preserve, for a detailed pilot study in order to test this hypothesis. The preserve is located about 34 km east of Gainesville, Florida and makes an excellent research site because it is maintained in a pristine state as it is closed off to public access. Two intensive samplings were completed, one in the "dry" season (March 2002) and one in the "wet" season (August 2003). In addition, periodic sampling trips were made to the lake every few weeks to evaluate the spatial and temporal patterns of radon distribution. A 222Rn mass balance was constructed for the lake to evaluate radon fluxes. Once the 222Rn fluxes were determined, groundwater inputs were estimated by dividing these fluxes by the concentration of radon in the water seeping into the lake. The radon concentration is estimated by sediment equilibration experiments using grab samples of sediment and radon activity measurements from monitor wells. We also constructed a traditional hydrologic water budget for Lake Barco. All hydrological variables were either measured or estimated and substituted into a water balance equation, which was then solved for the net groundwater flow term. These estimates were then compared to those from the 222Rn model. Our 222Rn measurements show little discernible spatial variation of radon inventories in the lake on any given day of sampling. Inventories measured at five different stations during the two different intensive sampling trips were all within ±13% of the mean value for each sampling. This amount of variation is considered insignificant, as the estimated analytical variation for the radon measurements is ±10%. We also found that we can estimate the lake inventory at any one station by collecting triplicate samples approximately one meter over the bottom at a single central sampling station. However, our results did display significant temporal variability, responding to rainfall trends that can influence the recharge rates. So, in a lake the size of Lake Barco (12 ha), reasonable groundwater discharge estimates at any given time can be made by triplicate analysis of radon in near-bottom waters and collection and processing of a few sediment samples. The estimations of groundwater discharge to the lake over the period of our study were, on average, 13,000 m3/month and 18,000 m3/month for the radon model and hydrologic budget, respectively. The water balance based estimate might be somewhat low due to differences in hydrogeologic movement under such dry conditions or the large error associated with budget estimations. Considering the large uncertainties in estimating groundwater flow via a hydrologic budget, agreement within a factor of two is considered satisfactory.
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Date Issued: 2004
Identifier: FSU_migr_etd-0395
Format: Thesis

Title: Assessment of Mercury (II) Species Bioavailability Using a Bioluminescent Bacterial Biosensor.
Creator: Barrocas, Paulo Rubens Guimarães, Landing, William M., Reeves, Robert H., Proctor, Lita M., Kostka, Joel E., Chanton, Jeffrey P., Department of Earth, Ocean and Atmospheric...
Show moreBarrocas, Paulo Rubens Guimarães, Landing, William M., Reeves, Robert H., Proctor, Lita M., Kostka, Joel E., Chanton, Jeffrey P., Department of Earth, Ocean and Atmospheric Sciences, Florida State University
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Abstract/Description: The objective of this research was to investigate the bioavailability of various Hg(II) species in laboratory and natural solutions using a bioluminescent bacterial biosensor. The Hg(II) bacterial biosensor is a genetically engineered E. coli strain, which produces firefly luciferase in proportion to its exposure to bioavailable Hg(II). The amount of luciferase inside the cells is assessed through its bioluminescent reaction with luciferin. A new analytical protocol for the use of bacterial...
Show moreThe objective of this research was to investigate the bioavailability of various Hg(II) species in laboratory and natural solutions using a bioluminescent bacterial biosensor. The Hg(II) bacterial biosensor is a genetically engineered E. coli strain, which produces firefly luciferase in proportion to its exposure to bioavailable Hg(II). The amount of luciferase inside the cells is assessed through its bioluminescent reaction with luciferin. A new analytical protocol for the use of bacterial bioassays to study the bioavailability of trace elements and relate it to their modeled chemical speciation was developed. The biosensor showed high specificity for Hg(II) and good reproducibility. The detection limit of the method (0.7 pM) is superior to most of the other reported Hg(II) biosensors and adequate to analyze mercury bioavailability at natural levels. The feasibility of using this new biosensor method to analyze natural samples was assessed. An approach for estimating conditional equilibrium constants for the complexation of Hg(II) by natural ligands is presented. The influence of inorganic and organic ligands on the Hg(II) speciation and bioavailability was investigated. Chloride titration results suggested that neutral HgCl20 and Hg(OH)20 complexes were more bioavailable than anionic Hg(II) chloride complexes. The addition of EDTA decreased the biosensor's response in both synthetic solutions and natural samples. This reduction was proportional to the total EDTA concentration. Kinetic experiments were performed to evaluate the Hg(II) uptake process by the bacterial biosensor. The experimental data agreed with the ultrasensitive kinetic model proposed for the Mer R protein response to Hg(II). The half-saturation constant for the enzymatic reaction was estimated. The Hg biosensor response displayed non-linear increases to both increasing exposure times and Hg(II) concentrations. According to the kinetic results, both non-linear behaviors are probably due to the saturation of the mer operon/Mer R protein with Hg(II). The analysis of the biosensor cells for their total Hg(II) concentration during a kinetic assay revealed no evidence for saturation of the Hg(II) uptake process. The kinetic results agree with the titration data and support the hypothesis that the diffusion of neutral Hg(II) complexes is an important Hg(II) uptake mechanism for bacterial cells.
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Date Issued: 2004
Identifier: FSU_migr_etd-1114
Format: Thesis

Title: Assimilation of Airs Radiance Observations into a Mesoscale Model: Adjoint Development, Quality Control, and Assimilation Results.
Creator: Carrier, Matthew J. (Matthew James), Zou, Xiaolei, Van Engelen, Robert A., Hart, Robert, Bourassa, Mark A., Liu, Guosheng, Department of Earth, Ocean and Atmospheric Sciences,...
Show moreCarrier, Matthew J. (Matthew James), Zou, Xiaolei, Van Engelen, Robert A., Hart, Robert, Bourassa, Mark A., Liu, Guosheng, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
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Abstract/Description: Radiance data obtained from NASA's Advanced Infrared Sounder (AIRS) is used in an attempt to improve the mesoscale prediction of temperature and moisture using one- and four-dimensional variational data assimilation (1D/4D-Var). The joint National Center for Atmospheric Research and Pennsylvania State University fifth-generation mesoscale model (MM5) along with the Stand-alone AIRS Radiative Transfer Algorithm (SARTA) is selected for this project. This work aims to utilize AIRS "clear-channel...
Show moreRadiance data obtained from NASA's Advanced Infrared Sounder (AIRS) is used in an attempt to improve the mesoscale prediction of temperature and moisture using one- and four-dimensional variational data assimilation (1D/4D-Var). The joint National Center for Atmospheric Research and Pennsylvania State University fifth-generation mesoscale model (MM5) along with the Stand-alone AIRS Radiative Transfer Algorithm (SARTA) is selected for this project. This work aims to utilize AIRS "clear-channel" radiances to enhance the first-guess analysis regarding the temperature and moisture content as a precursor to improving short-term precipitation forecasts. The adjoint operator for SARTA has been derived and linked to the MM5 adjoint modeling system; a "clear-channel" identification scheme, which is compatible with SARTA, has been developed and verified; and a set of one-dimensional variational data assimilation (1D-Var) experiments have been done in order to determine the impact of AIRS channels on the vertical profiles of temperature and moisture. Lastly, a preliminary 4D-Var experiment is carried out to determine the impact of a limited number of clear-channel AIRS radiances on the prediction of temperature and moisture. An adjoint-sensitivity based forecast verification technique is used to compare the 4D-Var forecast results to a control forecast.
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Date Issued: 2008
Identifier: FSU_migr_etd-4155
Format: Thesis

Title: Assimilation of GPS Radio Occultation Observations.
Creator: Shao, Hui, Zou, Xiaolei, Navon, Ionel M., Liu, Guosheng, Ray, Peter S., Krishnamurti, T. N., Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Unlike conventional and satellite observations, the Global Positioning System (GPS) radio occultation (RO) techniques provide all-weather, high-vertical-resolution observations that require no calibration. In this dissertation, the assimilation of GPS RO data is studied using the National Centers for Environmental prediction (NCEP) three dimensional variational analysis system. Three GPS data assimilation choices are considered and compared. A set of GPS bending angle assimilation (BA)...
Show moreUnlike conventional and satellite observations, the Global Positioning System (GPS) radio occultation (RO) techniques provide all-weather, high-vertical-resolution observations that require no calibration. In this dissertation, the assimilation of GPS RO data is studied using the National Centers for Environmental prediction (NCEP) three dimensional variational analysis system. Three GPS data assimilation choices are considered and compared. A set of GPS bending angle assimilation (BA) experiments is first carried out and sensitivity of BA results to the observational weighting, the quality of the background fields, the variation of the gravity, and the vertical resolution of the GPS data are investigated. The GPS local refractivity assimilation (REF) is then conducted and compared with BA. Although REF is computationally cheaper than BA, the bias and root mean square errors of the background fields are more significantly reduced by BA than REF. Differences between GPS refractivity and bending angle assimilations are larger in thick-layered cloud systems (e.g., convective clouds in the mid-latitudes and cumulus clouds in the tropics) than in thin clouds and clear sky, which are found to be associated with the strength of horizontal gradient of the atmospheric refractivity. Aiming at achieving both accuracy and computational efficiency, a new observation operator that simulates the GPS excess phase delay is proposed and tested for GPS RO data assimilation. Using the excess phase delay, the along-track refractivity and refractivity gradient information can be included while the computational cost is kept low. Numerical results from the forward simulation and data assimilation using the excess phase delay (PHA) are compared with those of REF. PHA tends to produce a warmer and wetter model atmosphere, with finer structures and larger radii of influence than REF. Compared to GPS observations, simulations and analyses produced by PHA are more accurate than those of REF. It is also pointed out that under the assumption of the spherical symmetry of the local refractivity, the observation operator for the excess phase delay simplifies into a point scheme in which only a vertical profile of model refractivity is required.
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Date Issued: 2005
Identifier: FSU_migr_etd-0301
Format: Thesis

Title: Assimilation of Hyperspectral Satellite Radiance Observations within Tropical Cyclones.
Creator: Lin, Haidao, Zou, Xiaolei, Niu, Xufeng, Ellingson, Robert G., Liu, Guosheng, Hart, Robert, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: The availability of high resolution temperature and water vapor data is critical for the study of mesoscale scale weather phenomena (e.g., convective initiations, and tropical cyclones). As hyperspectral infrared sounders, the Atmospheric Infrared Sounder (AIRS) and Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) could provide high resolution atmospheric profiles by measuring radiations in many thousands of different channels. This work focuses on the assessment of the potential...
Show moreThe availability of high resolution temperature and water vapor data is critical for the study of mesoscale scale weather phenomena (e.g., convective initiations, and tropical cyclones). As hyperspectral infrared sounders, the Atmospheric Infrared Sounder (AIRS) and Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) could provide high resolution atmospheric profiles by measuring radiations in many thousands of different channels. This work focuses on the assessment of the potential values of satellite hyperspectral radiance data on the study of convective initiations (CI) and the assimilation of AIRS radiance observations within tropical storms. First, the potential capability of hyperspectral infrared measurements (GIFTS) to provide convective precipitation forecasts has been studied and assessed. Using both the observed and the model-predicted profiles as input to the GIFTS radiative transfer model (RTM), it is shown that the simulated GIFTS radiance could capture the high vertical and temporal variability of the real and modeled atmosphere prior to a convective initiation, as well as the differences between observations and model forecasts. This study suggests the potential for hyperspectral infrared radiance data to make an important contribution to the improvement of the forecast skill of convective precipitation. Second, as the first step toward applying AIRS data to tropical cyclone (TC) prediction, a set of dropsonde profiles during Hurricane Rita (2005) is used to simulate AIRS radiance data and to assess the ability of AIRS data in capturing the vertical variability within TCs through one-dimensional variational (1D-Var) twin experiments. The AIRS observation errors and background errors are first estimated. Five sets of 1D-Var twin experiments are then performed using different combinations of AIRS channels. Finally, results from these 1D-Var experiments are analyzed. Major findings are: (1) AIRS radiance data contain useful information about the vertical variability of the temperature and water vapor within hurricanes; (2) assimilation of AIRS radiances significantly reduced errors in background temperature in the lower troposphere and relative humidity in the upper troposphere; (3) the near-real time (NRT) channel set provided by NOAA/NESDIS seems sufficient for capturing the vertical variability of the atmosphere in the upper troposphere of TCs, but not in the lower troposphere; and (4) the channels with weighting functions peak within the layer between 500-700 hPa could provide useful information to the atmospheric state below 700 hPa. A channel selection method is proposed to capture most vertical variability of temperature and water vapor within TCs contained in AIRS data. Finally, AIRS radiance data within TCs have been assimilated in the 1D-Var experiments with comparisons of the retrieval temperature and water vapor profiles with co-located Global Positioning System (GPS) radio occultation (RO) soundings and dropsonde profiles. The comparisons of AIRS 1D-Var retrieval profiles with GPS RO sounding show that AIRS data can greatly improve the analysis of temperature and water vapor profiles within TCs. The comparisons of retrieval profiles with dropsonde data during Hurricane Rita, however, showed some discrepancies partly due to the difference of these two measurements and the uncertainties of the AIRS errors.
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Date Issued: 2010
Identifier: FSU_migr_etd-1326
Format: Thesis

Title: Assimilation of Lightning Data Using a Nudging Method Involving Low-Level Warming.
Creator: Marchand, Max R., Fuelberg, Henry, Ahlquist, Jon, Hart, Robert, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: This study presents a new method for assimilating lightning data into numerical models that is suitable for cloud-resolving scales (e.g., 3 km). The study utilized data from the Earth Networks Total Lightning Network at 9 km grid spacing to mimic the resolution of the Geostationary Lightning Mapper (GLM) that will be on the upcoming GOES-R satellites. The assimilation procedure was developed using the Weather Research and Forecasting (WRF) numerical model. The method (denoted MU) warms the...
Show moreThis study presents a new method for assimilating lightning data into numerical models that is suitable for cloud-resolving scales (e.g., 3 km). The study utilized data from the Earth Networks Total Lightning Network at 9 km grid spacing to mimic the resolution of the Geostationary Lightning Mapper (GLM) that will be on the upcoming GOES-R satellites. The assimilation procedure was developed using the Weather Research and Forecasting (WRF) numerical model. The method (denoted MU) warms the most unstable low levels of the atmosphere at locations where lightning was observed but deep convection was not simulated based on the absence of graupel. Simulation results utilizing the new method are compared with a control simulation and a simulation employing the lightning assimilation method (FO) developed by Alexandre Fierro and colleagues. Unlike MU, the FO method increases relative humidity according to a nudging function dependent on the intensity of observed lightning and simulated graupel mixing ratio. Simulations are performed across the Central and Eastern United States for three separate severe storm cases during 2011. These cases exhibit a wide range of weather patterns and thunderstorm organization. When comparing simulation results with hourly NCEP stage IV radar and gauge precipitation observations, both the MU and FO assimilation methods produce an improved simulated precipitation field during the assimilation period and a short time afterwards based on subjective comparison and objective statistical scores. The assimilation methods commonly improve equitable threat scores by more than 0.1 and 50% during the assimilation period. Differing degrees of improvement from the assimilation methods depend on the weather pattern, with the MU method generally performing better in the simulation of isolated thunderstorms and other weakly forced deep convection. Biases in the precipitation, moisture, and temperature fields of the simulations also are examined and sometimes differ considerably between assimilation schemes. Based on performance and bias, the newly developed MU method is shown to be a viable alternative to the FO method, exhibiting utility in producing and locating thunderstorms where observed and providing a better analysis at low computational cost.
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Date Issued: 2013
Identifier: FSU_migr_etd-7490
Format: Thesis

Title: Atlantic Reconnaissance Vortex Message Climatology and Composites and Their Use in Characterizing Eyewall Cycles.
Creator: Piech, David J., Hart, Robert, Clayson, Carol Anne, Fuelberg, Henry, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: There has been great energy focused on tropical cyclone intensity forecasting over the past thirty years. Toward the goal of providing more accurate intensity forecasts, the role of the environment of a tropical storm has been studied at great length over the past few years while the storm itself has not. There remains considerable work left toward understanding how the tropical cyclone structure itself can be used to aid intensity forecasting. One step toward this goal for the Atlantic is by...
Show moreThere has been great energy focused on tropical cyclone intensity forecasting over the past thirty years. Toward the goal of providing more accurate intensity forecasts, the role of the environment of a tropical storm has been studied at great length over the past few years while the storm itself has not. There remains considerable work left toward understanding how the tropical cyclone structure itself can be used to aid intensity forecasting. One step toward this goal for the Atlantic is by dissecting a climatology of reconnaissance vortex message reports from the Atlantic basin between 1989 and 2005. Such an analysis will permit the comparison of tropical cyclone core structure measurements to know future intensity change. This vortex message data, which is collected from dropsondes and radar during flights into tropical disturbances, includes eye size, pressure, eye temperature, eye dewpoint, maximum flight level winds and other pertinent information. The number of occurrences for each vortex message characteristic as well as frequency plots of eye type, Julian day, latitude, longitude, temperature, dewpoint, and intensity change as a function of mean sea level pressure (MSLP) and eye size were created. The composite mean eyewall cycle was analyzed, along with the cycles of concentric eyewalls and elliptical eyewalls. Based on this vortex message climatology and analysis, an eyewall phase diagram was developed that graphically shows the evolution of a storm. These eyewall phase diagrams show how eyewall cycles evolve in time using mean MSLP, mean eye size, concentric eyewall frequency, and elliptical eyewall frequency data. Case studies include analysis of a storm undergoing an eyewall replacement cycle (Rita 2005), a rapidly weakening storm (Charley 2004), and a rapidly intensifying storm (Wilma 2005). It was discovered in this study that core storm data collected from vortex data messages could be used to confirm theories on tropical cyclone intensity. Preliminary attempts at simple forecasts comparing eye characteristics and future intensity change were done. Indeed, short-term forecasts of intensity change should utilize storm-specific structure, beginning with an analysis of that structure in intensification versus weakening events. Further work involving pattern matching trajectories and trajectory segments to forecast future storm trajectory in the eyewall phase diagram may lead to helpful analog tropical cyclone intensity forecast guidance.
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Date Issued: 2007
Identifier: FSU_migr_etd-0888
Format: Thesis

Title: Atmospheric Mercury Input to the Pensacola Bay Watershed.
Creator: Cleveland, Sara D., Landing, William M., Froelich, Philip, Huettel, Markus, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: By sampling individual rain events over a 1-year period at three sites situated around a known point source of atmospheric mercury, we have attempted to quantify its influence on local mercury deposition. A suite of trace elements was also analyzed on these rain event samples. A multi-element analytical program was set up using a Thermo-Finnigan "Element" ICP-MS. We identified 46 elements that are significantly enriched in rain samples relative to the method blank, including the alkali metals...
Show moreBy sampling individual rain events over a 1-year period at three sites situated around a known point source of atmospheric mercury, we have attempted to quantify its influence on local mercury deposition. A suite of trace elements was also analyzed on these rain event samples. A multi-element analytical program was set up using a Thermo-Finnigan "Element" ICP-MS. We identified 46 elements that are significantly enriched in rain samples relative to the method blank, including the alkali metals and alkaline earth elements, all three rows of the transition metals, and the rare earth elements. The total mercury concentrations in the rainwater samples ranged from 2-40 ng/L. The volume weighted mean rainfall mercury concentrations ranged from 9.2-9.8 ng/L, and there were no significant differences in the rainfall Hg deposition between the three sites. Principal component factor analysis (PCFA) was used to evaluate co-variance between mercury and trace element deposition. PCFA showed a strong crustal factor, a strong sea-salt factor, a mysterious "P" factor and a strong mercury factor. The mercury factor linked mercury with Bi, Ga, Pb, Sb and V. Plume dispersion modeling and air-mass back trajectory analysis have been conducted for each rain event. The goal of this research was to use mercury and trace element relationships in an effort to identify, and quantify, the impacts from various emission sources in the region on rainfall chemistry. We calculated the annual integrated percent of mercury associated with coal burning ranging between 15-47%. Using models to estimate the impact of local deposition we found that less than 1% of the mercury we measured is from the known point source.
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Date Issued: 2006
Identifier: FSU_migr_etd-3582
Format: Thesis

Title: Atmospheric Power-Law Behavior: A Look into Southeastern US Daily Temperature Extremes.
Creator: Duncan, James Bean, Sura, Philip, Wu, Zhaohua, Bourassa, Mark, Stefanova, Lydia, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Extreme events are phenomena which occupy the tail-end of a distributions PDF. While atmospheric phenomena are decidedly non-Gaussian, the exact shape of these tails of a distribution are relatively unknown. From stochastic theory, it is noted that tails or extremes may be predicted by the behavior of power-law distribution. While prior research for the empirical search for power-laws has been heavily qualitative in nature, this study aims at the quantitative and statistical fitting and...
Show moreExtreme events are phenomena which occupy the tail-end of a distributions PDF. While atmospheric phenomena are decidedly non-Gaussian, the exact shape of these tails of a distribution are relatively unknown. From stochastic theory, it is noted that tails or extremes may be predicted by the behavior of power-law distribution. While prior research for the empirical search for power-laws has been heavily qualitative in nature, this study aims at the quantitative and statistical fitting and analysis of power-laws across the southeastern United States with respect to daily maximum and minimum temperatures. Utilizing a power-law fitting algorithm, we may fit power-law distributions to the PDFs of atmospheric maximum and minimum temperatures. After statistical analysis, we may note the universal significance of these power-law tails throughout the southeastern United States within regions of non-Gaussianity. Further, we analyze varying behavior of these significant power-laws within the distribution's PDF. From this, we may note and observe the behavior of these extremes events in relation to weather and climatic cycles.
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Date Issued: 2013
Identifier: FSU_migr_etd-7362
Format: Thesis

Title: Attributing Contributions to the Seasonal Cycle of Anthropogenic Warming in a Simple Radiative- Convective Global Energy Balance Model.
Creator: Sejas, Sergio A., Cai, Ming, Ellingson, Robert G., Wu, Zhaohua, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: A simple one-dimensional seasonal atmosphere-ocean energy balance model is used to study the seasonal and latitudinal response of the model climate to a doubling of the CO2 concentration. A new climate feedback analysis method, formulated in Lu and Cai (2009a), is used to isolate contributions (partial temperature changes) of the external forcing alone and subsequent feedbacks to the total temperature change experienced by the model climate. In this study, the relative importance of the...
Show moreA simple one-dimensional seasonal atmosphere-ocean energy balance model is used to study the seasonal and latitudinal response of the model climate to a doubling of the CO2 concentration. A new climate feedback analysis method, formulated in Lu and Cai (2009a), is used to isolate contributions (partial temperature changes) of the external forcing alone and subsequent feedbacks to the total temperature change experienced by the model climate. In this study, the relative importance of the external forcing alone (the CO2 doubling), surface ice-albedo feedback, water vapor feedback, changes in poleward heat transport, changes in vertical sensible heat flux, and changes in heat storage are analyzed. The partial temperature change due to the water vapor feedback is substantially the largest contributor to the globally averaged surface warming. The ice-albedo feedback plays a smaller role, but also significantly contributes to the overall warming of the surface. The most important negative feedback, counteracting the surface warming, is the change in the vertical sensible heat flux. However, though the water vapor feedback is most responsible for the overall surface warming, it is not the feedback most responsible for the seasonal and spatial pattern of the surface warming. The climate of this model indicates that there is a surface polar warming amplification, with a maximum occurring in late summer/early fall. The feedback most responsible for this polar warming amplification and seasonal pattern in this model is the surface ice-albedo feedback, which is largest at high latitudes in summer.
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Date Issued: 2011
Identifier: FSU_migr_etd-0278
Format: Thesis

Title: Balanced and Unbalanced Flow in Primitive Equation Model Simulations of Baroclinic Wave Life Cycles.
Creator: Hayes, Philip Doyle, Cunningham, Philip, Reasor, Paul, Krishnamurti, T. N., Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Simulations of baroclinic wave life cycles are performed in order to illustrate the wave evolution of a cyclone and diagnose possible unbalanced flow associated with the destabilization of an upper-level jet. Development of the baroclinic wave is observed using the multilevel primitive equation Weather Research and Forecasting (WRF) model. A baroclinic system is produced with an initially balanced, zonal baroclinic jet on an f-plane, whereby the geometry of the dynamic tropopause is specified...
Show moreSimulations of baroclinic wave life cycles are performed in order to illustrate the wave evolution of a cyclone and diagnose possible unbalanced flow associated with the destabilization of an upper-level jet. Development of the baroclinic wave is observed using the multilevel primitive equation Weather Research and Forecasting (WRF) model. A baroclinic system is produced with an initially balanced, zonal baroclinic jet on an f-plane, whereby the geometry of the dynamic tropopause is specified. The change in geometry will result in different initial jet profiles. For each jet profile two numerical simulations comprised of different diffusion parameters are integrated to show the effect that the diffusion has on the simulation. The first simulation consists of a combination of weak horizontal and strong vertical diffusion, while the second simulation includes only strong horizontal diffusion, and is considered to be more consistent with real atmosphere characteristics. For each simulation, the nonlinear stage of the life cycle resembles a cyclonic wave-breaking system. Simulations where the vertical diffusion is strong tend to produce events of secondary cyclogenesis, which are not observed in the case of strong horizontal diffusion. Therefore, these secondary events are in all probability results of numerical instabilities at the triple point of the baroclinic system. The simulations with strong horizontal diffusion produce a crisper version of the baroclinic wave evolution cycle with sharper temperature gradients and deeper surface lows than the strong vertical diffusion case. Diagnostic calculations of the horizontal divergence and the residual of the nonlinear balance equation are shown in order to identify areas of unbalanced flow and subsequent inertia-gravity waves. Banded structures in the horizontal divergence field at the level of maximum wind speed suggest that the unbalanced flow is closely related to the upper level jet streak and possibly generated through geostrophic adjustment processes. The simulations with strong vertical diffusion contain less numerical noise and provide a clearer insight into the possible existence of inertia-gravity waves. A breakdown into the three main components of the residual of the nonlinear balance equation is shown in order to asses the contribution of each term towards the production of unbalanced flow, and indicates that the Laplacian term was the dominant factor as it was an order of magnitude stronger than the Jacobian and vorticity terms.
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Date Issued: 2005
Identifier: FSU_migr_etd-4192
Format: Thesis

Title: The Bering Strait and the Southern Ocean Winds' Grip on the World Climate.
Creator: De Boer, Agatha M., Nof, Doron, Hunter, Christopher, Burnett, William, Clarke, Alan J., Speer, Kevin, Weatherly, Georges L., Department of Earth, Ocean and Atmospheric Sciences,...
Show moreDe Boer, Agatha M., Nof, Doron, Hunter, Christopher, Burnett, William, Clarke, Alan J., Speer, Kevin, Weatherly, Georges L., Department of Earth, Ocean and Atmospheric Sciences, Florida State University
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Abstract/Description: The Bering Strait's Grip On The World Climate: The Holocene interglacial period of the last 10,000 years and the penultimate interglacial ~125,000 years ago have been characterized by distinctly stable climates. During the intervening glacial period, climate records are marked by rapid large-amplitude oscillations, general known as Dansgaard-Oeschger events. These millennial-scale cycles are generally believed to be a result of freshwater anomalies in the North-Atlantic, followed by a...
Show moreThe Bering Strait's Grip On The World Climate: The Holocene interglacial period of the last 10,000 years and the penultimate interglacial ~125,000 years ago have been characterized by distinctly stable climates. During the intervening glacial period, climate records are marked by rapid large-amplitude oscillations, general known as Dansgaard-Oeschger events. These millennial-scale cycles are generally believed to be a result of freshwater anomalies in the North-Atlantic, followed by a reorganization of the thermohaline circulation. Here, we propose that such long lasting instabilities in the thermohaline circulation are only possible during glacial periods when the Bering Strait (BS) is closed. A semi-global analytical ocean model (which includes both wind and thermohaline processes) is used to show that, during interglacial periods (when the BS is open) perturbations in North Atlantic Deep Water (NADW) formation are rapidly damped out because of a novel BS freshwater feedback mechanism. This new feedback mechanism is due to the strong winds in the Southern Ocean (SO) which, with an open BS, quickly [O(10)years)] flush any low salinity anomalies out of the Atlantic and into the Pacific Ocean. During glacial periods, the stabilizing feedback is prevented by the closure of the BS which traps the anomalies within the Atlantic, causing long lasting perturbations. The sensitivity of the mean stable state to steady changes in the external forcing, namely the wind or the precipitation field, is also tested. A relevant example is a prolonged increase in precipitation due to anthropogenic warming, (predicted by global circulation models). We find that both stronger winds (especially the SO Winds) and a decrease in precipitation over the North Atlantic (NA) will lead to a new (stable) enhanced overturning. Conversely, weaker winds or increased precipitation will reduce the overturning to a slower stable state. The Island Wind-Bouyancy Paradox: In reent years, a variety of studies have suggested that the meridional overturning circulation is at least partially controlled by the Southern Ocean winds. The paraadoxical implication is that a link exists between the surface bouyancy flux to the ocean (which is needed for the density transfor4matio between surface and deep water) and the wind. These forcings have traditionally been viewed as independent drivers of the ocean circulation. Here, the paradox is formally stated in the framework of a gigantic island that lies between latitude bands free of continents (such as the land mass of the Americas). The choice of such an island on a sphere was made because it enables one to obtain analytical solutions and it circumvents the need to calculate the torque exerted on zonal sills adjacent to the island tips (e.g., the Bering Strait). The torque calculation is notoriously difficult and is avoided here by the clockwise integration which goes twice through the western boundary of the island (in opposite directions) eliminating any unknown pressure torques. The derived wind-driven overturning is shown to be consistent with Godfrey's Island Rule when the rule is extended to include the sinking or upwelling adjacent to the island. In addition, the consideration of vertical exchange in the Island Rule eliminates the need to make the level-of-no-motion assumption. The paradox is resolved quanlitatively, using salinity and temperature mixed dynamical-box models and a temperature slab model, and quantitatively, employing a numerical model. We show that in all cases the ocean stratification and thermocline depth adjust themselves to allow the overturning imposed by the wind. The salinity and temperature box model suggests that stronger southern winds will tend to weaken the virtical and horizontal salinity stratfication so that it is esier for the conversion of deep to surface water (and vice versa) to take place. A temperature slab model (i.e., y-dependent)offers a more detailed picture;stronger southern winds flatten the meridional temperature profile and shift it northwards (so that it lags the atmospheric temperature). The (process orientated) numericl model is adapted to include a thermodynamic parameterization for the surface heat and freshwater fluxes. In response to stronger southern winds, the thermocline thickens in the north, releases more heat to the atmosphere and, therefore, converts more surface to deep water.
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Date Issued: 2003
Identifier: FSU_migr_etd-0336
Format: Thesis

Title: The Biochemical Composition of Naupii Derived from Stored Non-Diapause and Diapause Copepod Eggs and the Biology of Diapausing Eggs.
Creator: Sedlacek, Christopher, Marcus, Nancy, Keller, Laura, Thistle, David, Huettel, Markus, Kostka, Joel, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Mariculture of fish is needed to support our ever growing global population. Copepods are a natural and beneficial source of first feed for many marine fish species, but it can be difficult to hatch enough when the fish are ready to feed. Therefore, storage of copepod eggs for use at a later date increases the potential of nauplii to be used as a commercial food source. There are two types of eggs produced by copepods: diapause and non-diapause (or subitaneous). However, little is known about...
Show moreMariculture of fish is needed to support our ever growing global population. Copepods are a natural and beneficial source of first feed for many marine fish species, but it can be difficult to hatch enough when the fish are ready to feed. Therefore, storage of copepod eggs for use at a later date increases the potential of nauplii to be used as a commercial food source. There are two types of eggs produced by copepods: diapause and non-diapause (or subitaneous). However, little is known about diapause or the effects and duration of storage, either under cold or warm temperature conditions, on the biochemical composition of nauplii. Little is also known about the development of embryos that enter diapause. Diapause requires a refractory period before development of the embryo continues. The refractory period can last for several months regardless of environmental conditions. I studied the effects of both cold storage and cold storage with the addition of antibiotics on non-diapause eggs of the copepod Acartia tonsa and duration of storage for diapause eggs produced by Centropages hamatus and compared those results to nauplii derived from non-diapause eggs. The organic components analyzed to determine if potential changes were occurring during storage were lipids, fatty acids, proteins, free amino acids, and carbohydrates as well as the percent hatch of the eggs and the dry weight of the resultant nauplii. To understand diapause, we utilized two stains, one to determine the number of nuclei present and another to determine intracellular pH of the diapausing eggs. Acartia tonsa eggs stored for up to15 days at 1°C did not indicate any change in the biochemical make-up of the resulting nauplii. The only change we observed was in the viability of the eggs, which decreased at a steady rate over time. The viability of the eggs quickly approached zero percent hatch beyond 15 days. The addition of the antibiotic oxytetracyclin at a 10% concentration did not change the naupliar biochemistry and did not increase viability over the storage time. Centropages hamatus eggs maintained a high level of viability over the course of 13 months of storage under anoxic conditions. The nauplii derived from the diapause eggs stored at 25°C had similar biochemical components regardless of the length of the storage period. My study indicates that storage of A. tonsa and C. hamatus may not affect the nutritional value of the nauplii for aquaculture purposes. We also determined that the embryos of C. hamatus stopped developing after ~7 cleavages. The diapausing embryos also maintained an intracellular pH similar to the surrounding water and acidified when beginning to develop. This is the first time the intracellular pH and only the third time the nuclei of a copepod diapausing egg has been determined. This information could allow future researchers to interrupt diapause and induce the eggs to hatch before the end of the refractory period.
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Date Issued: 2008
Identifier: FSU_migr_etd-0283
Format: Thesis

Title: Biogeochemical Cycling of Carbon, Phosphorus, and Trace Metals.
Creator: Stern, Jennifer Claire, Wang, Yang, Salters, Vincent J.M., Chanton, Jeffrey, Odom, A. Leroy, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Carbon isotopes were used as tracers in the Florida Everglades to investigate the sources and sinks of dissolved organic carbon in natural and constructed wetlands and provide a way to monitor ecosystem restoration efforts. Stable carbon isotopes were used to determine the source of DOC and POC, and in a basic mass balance model to calculate turnover times of DOC in small constructed wetland cells. Radiocarbon was used to distinguish "old" DOC derived from historic peats from "new" DOC...
Show moreCarbon isotopes were used as tracers in the Florida Everglades to investigate the sources and sinks of dissolved organic carbon in natural and constructed wetlands and provide a way to monitor ecosystem restoration efforts. Stable carbon isotopes were used to determine the source of DOC and POC, and in a basic mass balance model to calculate turnover times of DOC in small constructed wetland cells. Radiocarbon was used to distinguish "old" DOC derived from historic peats from "new" DOC derived from modern primary production. Our study suggests that Ä14C measurements can be a useful indicator of the progress of ecosystem restoration in the Everglades. The oxygen isotope of phosphate (P) can also serve as an isotopic tracer in wetlands. Initial method development to use the oxygen isotope of phosphate extracted from natural waters is presented here. Preliminary data indicates that microbial recycling is a major means by which P stays in the water column despite reducing anthropogenic contributions. Stable carbon isotopes were also used to quantify the percent of methane oxidized within Tallahassee landfill soils. Carbon isotope and oxidation data collected over almost 9 months of monitoring methane emissions from landfill surfaces with and without a "biocover" is examined. These measurements, combined with measurements of methane flux, can help monitor the efficiency of various treatments in reducing methane emissions to the atmosphere by enhancing oxidation of methane by methanogenic bacteria. The presence or absence of DOC in the water column can determine whether trace metals will be present as a nutrient or as a toxicant. A novel method coupling capillary electrophoresis with ICP-MS was used to separate metal species and calculate binding constants of rare earth elements and Th, Hf, and Zr with humic substances at a range of pH and ionic strength of 0.1. Equilibrium dialysis ligand exchange was performed to validate the CE-ICP-MS method. Conditional stability constants of tetravalent metal-HA complexes are several orders of magnitude higher than lanthanide-HA complexes. Because thorium is often used as a proxy for the tetravalent actinides, Th-HA binding constants are useful in the study of sequestration of actinides in nuclear repository settings.
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Date Issued: 2005
Identifier: FSU_migr_etd-1561
Format: Thesis

Title: Biostratigraphy and Comparison of Paleocene to Lower Eocene Calcareous Nannofossils from Broken Ridge and Ninety-East Ridge: Ocean Drilling Program Leg 121, Sites 752 and 758.
Creator: Millen, Hana Terese, Wise, Sherwood, Wang, Yang, Parker, William, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Ocean Drilling Program Site 752 on Broken Ridge in the Indian Ocean recovered an expanded section containing Paleocene and lower Eocene calcareous nannofossils. Qualitative counts show a diverse, high-latitude assemblage of primarily moderately preserved and abundant nannofossils. The assemblage was deposited in the high southern latitudes before Broken Ridge rifted off of the Kerguelen Plateau in the middle Eocene. Minor modifications allowed Okada and Bukry's 1980 low-latitude zonation to...
Show moreOcean Drilling Program Site 752 on Broken Ridge in the Indian Ocean recovered an expanded section containing Paleocene and lower Eocene calcareous nannofossils. Qualitative counts show a diverse, high-latitude assemblage of primarily moderately preserved and abundant nannofossils. The assemblage was deposited in the high southern latitudes before Broken Ridge rifted off of the Kerguelen Plateau in the middle Eocene. Minor modifications allowed Okada and Bukry's 1980 low-latitude zonation to be utilized at this site for Zones CP1a through CP10. Various markers such as the first occurrence of Discoaster diastypus and Tribrachiatus bramlettei, or the last occurrence of Fasciculithus sp., were used in past studies to determine the Paleocene/Eocene boundary. At this high-latitude site, both D. diastypus and T. bramlettei are rare or absent, so the last occurrence of Fasciculithus sp. was used to approximate the boundary. Ocean Drilling Program Site 758 cored the northern Ninety-East Ridge in the Indian Ocean. Ninety-East Ridge is a hotspot trace formed from the northward movement of the Indo-Australian Plate. This site contains a more condensed section in which much of the lower Paleocene and all of the lower Eocene are absent. A more generically diverse, but still high-latitude assemblage of nannofossils is examined in this study. First seen in Zone CP6, a large variety of Discoaster okadai is present at Site 758. Figures are presented to show the variation in morphology of this species in the Indian Ocean. Much research has been done to associate Paleogene nannofossil genera with different paleoceonographic conditions. Both Sites 752 and 758 show a shift from primarily small, cool-water, eutrophic species near the K/T boundary (such as Prinsius martinii, Prinsius dimorphosus, or Cruciplacolithus primus) to warm-water, oligotrophic species (such as Sphenolithus, Discoaster, or Zygrhablithus bijugatus). This trend is seen in Principal Component Analysis and is more obvious at Site 752 due to the presence of a complete lower Paleocene section and lower Eocene nannofossils.
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Date Issued: 2012
Identifier: FSU_migr_etd-5039
Format: Thesis

Title: Biostratigraphy and Paleoecology of the Calvert Formation, Eastern Maryland.
Creator: Jemison, Kelly, Wise, Sherwood, Tull, James, Burnett, William, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: ABSTRACT High-resolution biostratigraphic data were collected from two cores drilled in 2007 and 2009 by the United States Geological Survey at the South Dover Bridge (SDB) and the Cambridge-Dorchester (Cam-Dor) Airport in eastern Maryland. The objectives of this study are to assess the down-core diatom abundances in order to build on a biostratigraphic framework that has been established for the Miocene Calvert Formation (Chesapeake Group) of the Atlantic Coastal Plain. Samples were prepared...
Show moreABSTRACT High-resolution biostratigraphic data were collected from two cores drilled in 2007 and 2009 by the United States Geological Survey at the South Dover Bridge (SDB) and the Cambridge-Dorchester (Cam-Dor) Airport in eastern Maryland. The objectives of this study are to assess the down-core diatom abundances in order to build on a biostratigraphic framework that has been established for the Miocene Calvert Formation (Chesapeake Group) of the Atlantic Coastal Plain. Samples were prepared using a strewn mounting method and examined via light microscopy for relative abundances. The Shannon diversity index was used to measure the species richness throughout the cores, and hierarchical cluster analysis was used to group the diatoms to determine the degree of similarity between species and to determine whether other relationships between species and depths could be measured. The biostratigraphy was used to infer paleoecology, climatic trends, and sea-level fluctuations as well as to correlate between the two cores. Existing calcareous nannofossil zonations were used to provide age control for the South Dover Bridge core based on a modified version of the East Coast Diatom Zonation (ECDZ) of Andrews (1976). Using this zonal scheme, both cores were assigned relative ages throughout the sampled section. Five zones were identified in the SDB core (ranging from Middle Burdigalian to Middle Serravalian) and four at the Cam-Dor site (Upper Burdigalian to Middle Serravalian). The Cam-Dor core penetrated a thicker section. The first occurrences of marker diatom species and the presence of an unconformity at both sites were used to correlate between the two sections. The diatom assemblages present are indicative a shallow-marine shelf environment that experienced fluctuations in sea level and were influenced by high energy events.
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Date Issued: 2012
Identifier: FSU_migr_etd-4926
Format: Thesis

Title: Boundary Layer Structure in Landfalling Tropical Cyclones.
Creator: Maxham, William D., Ruscher, Paul, Hart, Robert, Krishnamurti, T. N., Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: This study examines the changes in boundary layer of landfalling tropical cyclones. Several storms which made landfall near surface observation platforms capable of high resolution data storage were examined. These records were subjected to spectral methods to explore the characteristics of the changing boundary layer turbulence. These results were compared to recent observations of boundary layer roll features noted in some landfalling storms. Spectra were also used for determining...
Show moreThis study examines the changes in boundary layer of landfalling tropical cyclones. Several storms which made landfall near surface observation platforms capable of high resolution data storage were examined. These records were subjected to spectral methods to explore the characteristics of the changing boundary layer turbulence. These results were compared to recent observations of boundary layer roll features noted in some landfalling storms. Spectra were also used for determining turbulence dissipation rates in the storms. It was determined that only the highest resolution datasets available with a sampling rate of 5 Hz were adequate to explore the small scale features of the flow and to accurately describe the turbulence dissipation rates.
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Date Issued: 2004
Identifier: FSU_migr_etd-2653
Format: Thesis

Title: Broadband Solar Irradiances Measured on Fixed and Stabilized Platforms: Comparison of Observations and Their Uncertainties.
Creator: McDowall, Gregory, Ellingson, Robert, Ruscher, Paul H., Liu, Guosheng, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Over the past 40 years radiative transfer models have consistently under-predicted the amount of solar absorption by clouds. Estimates of the size of this discrepancy at the beginning of its discovery were ~10 W/m^2, but in 1995 jumped to 40-100 W/m^2, which ARESE I was formed to resolve. ARESE I being inconclusive, ARESE II was conducted and further studies brought the estimates back to ~10 W/m^2. Part of the problem lies with the difficulty of obtaining accurate measurements of the absorbed...
Show moreOver the past 40 years radiative transfer models have consistently under-predicted the amount of solar absorption by clouds. Estimates of the size of this discrepancy at the beginning of its discovery were ~10 W/m^2, but in 1995 jumped to 40-100 W/m^2, which ARESE I was formed to resolve. ARESE I being inconclusive, ARESE II was conducted and further studies brought the estimates back to ~10 W/m^2. Part of the problem lies with the difficulty of obtaining accurate measurements of the absorbed solar insolation as well as constructing models that represent real atmospheric conditions. So after ARESE II was completed an experiment was performed to test the effectiveness of a new technique-the stabilized platform. A pyranomter mounted on a stabilized platform, which kept the instrument on board the Proteus aircraft in the earth's horizontal plane, was used to measure the solar flux. Another pyranomter, mounted on a standard fixed platform, was also aboard the Proteus. Since the observations of the fixed platform have to be corrected for the movements and deformation of the aircraft, there is an additional source of uncertainty. Thus the aim of this study was to determine the flux and absorption uncertainties observed from the fixed and stabilized platforms. The fixed platform flux uncertainties, at 4.4-14.8 W/m^2, were ~1.8 times those of the stabilized platform which were 3.8-8.2 W/m^2. However, the fixed flux uncertainties were not so great as to invalidate the pre-ARESE I and ARESE I studies
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Date Issued: 2006
Identifier: FSU_migr_etd-2573
Format: Thesis

Title: Caffeine as an Anthropogenic Source Indicator in Freshwater and Marine Systems.
Creator: Peeler, Kelly Ann, Chanton, Jeffrey, Opsahl, Steven, Burnett, William, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Bacteria serve as traditional indicators of water quality. In the past decade, methods have been developed to explore the use of more human specific indicators. One of these suggested indicators is caffeine. Caffeine is widely consumed in populated areas and has already been proven as a successful indicator in freshwater systems. This project aimed to modify the caffeine extraction method to obtain ng/L detection limits and prove its usefulness as a tracer in marine systems. Optimal...
Show moreBacteria serve as traditional indicators of water quality. In the past decade, methods have been developed to explore the use of more human specific indicators. One of these suggested indicators is caffeine. Caffeine is widely consumed in populated areas and has already been proven as a successful indicator in freshwater systems. This project aimed to modify the caffeine extraction method to obtain ng/L detection limits and prove its usefulness as a tracer in marine systems. Optimal extractions were performed with solid phase extraction using traditional C-18 sorbent columns. Extracts were then run on a GC/MS. Freshwater samples were examined in this project to determine a background level of caffeine in relatively isolated areas. Analysis of samples from creeks in southwest Georgia did not detect caffeine. An isolated wetland sample did contain caffeine and led to the identification of a natural local source of caffeine, the Yaupon Holly. Samples were also collected along the Ochlockonee river system. Some of its tributaries known to have treated wastewater effluent were also sampled. Samples from these tributaries contained measurable caffeine, but caffeine was not found in the main stem. The marine system sampled was Sarasota Bay, Florida. There was no interference of salts in marine samples to compromise the method. Caffeine concentrations were found to be highest along the mainland side of the bay, where septic systems were suspected sources of contamination. Caffeine had an inverse relationship with salinity and conductivity and positive correlations with nutrient concentrations. Fecal coliforms correlated well with caffeine, but not with the more resilient enterococcus bacterium. Samples of groundwater were analyzed and proved a definite source of caffeine to this system. A degradation experiment found that in a natural sample of marine water exposed to sunlight, caffeine has a half-life of approximately 30 days. However, for samples kept in the dark the half-life increases to 71 days, and samples refrigerated at a constant 4oC and in the dark have a half-life of 178 days.
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Date Issued: 2004
Identifier: FSU_migr_etd-2056
Format: Thesis

Title: Calcareous Nannofossil Biostratigraphy, Evolution, and Taxonomy in Two Problematic Intervals: The Oligocene (ODP Leg 199) and Turonian (ODP Leg 207).
Creator: Blair, Stacie Ann, Wise, Sherwood W., Burnett, William, Parker, William C., Wang, Yang, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Calcareous nannofossils are used as biostratigraphic indicators integral for age control in both petroleum industry and academic settings. The Oligocene and Late Cretaceous are especially problematic for nannofossil biostratigraphers due to low diversity and species' concepts of gradually evolving lineages (Oligocene) and an absence of carbonate-rich deep-water sections (Upper Cretaceous). Sediments from Ocean Drilling Program (ODP) Leg 199 (eastern Equatorial Pacific) and Leg 207 (Demerara...
Show moreCalcareous nannofossils are used as biostratigraphic indicators integral for age control in both petroleum industry and academic settings. The Oligocene and Late Cretaceous are especially problematic for nannofossil biostratigraphers due to low diversity and species' concepts of gradually evolving lineages (Oligocene) and an absence of carbonate-rich deep-water sections (Upper Cretaceous). Sediments from Ocean Drilling Program (ODP) Leg 199 (eastern Equatorial Pacific) and Leg 207 (Demerara Rise) provide a unique opportunity to analyze nannofossil bioevents from complete, nearly continuous sections Oligocene and Upper Cretaceous in age. Chapter two analyzes calcareous nannofossil bioevents across the Oligocene-Miocene transition. Established nannofossil biostratigraphies for the Oligocene-Miocene transition exist; however, sections in which nannofossil bioevents can be finely tuned to the Geomagnetic Polarity Time Scale are rare. Ocean Drilling Program Leg 199, Site 1218, located in the eastern Equatorial Pacific recovered a near continuous Oligocene-Miocene boundary section with complete magnetostratigraphic and orbitally-paced stable-carbon and 'oxygen isotope records. This study examines calcareous nannofossils from ODP Site 1218 at 30-cm intervals across the Oligocene-Miocene transition. Seventeen nannofossil datum events between 24.65 and 21.69 Ma are identified and calibrated to the Site 1218 chronostratigraphic age model. Sphenolithus delphix is still the most precise nannofossil datum for the Oligocene/Miocene boundary; its top calibrated just ~30-ky below the Aquitanian Stage base at Site 1218 (23.06 Ma). Two robust acme events of Sphenolithus conicus (22.87-23.57 Ma) and Triquetrorhabdulus carinatus (22.26-22.87 Ma) also characterize the Oligocene-Miocene transition and are interpreted here to result from fluctuations in nutrient input across the Mi-1 cooling event. In addition, nannofossil preservation exhibits a strong correlation with the 400-ky and larger 1.2-Myr eccentricity and obliquity cycles. Chapters three and four analyze calcareous nannofossils from a rare Middle Cenomanian-Upper Turonian section from ODP Leg 207, Site 1260 (Demerara Rise, South America). This study observes 56 nannofossil bioevents spanning the Middle Cenomanian to uppermost Turonian providing a high-resolution calcareous nannofossil framework for this Upper Cretaceous interval: six Middle Cenomanian bioevents, 10 Upper Cenomanian bioevents, 14 Lower Turonian bioevents, 18 Middle Turonian bioevents, and 8 Upper Turonian bioevents. Thirty-two of these 56 nannofossil bioevents have been previously described in the literature. Nannofossil bioevents were calibrated to the 2008 timescale of Ogg et al. (2008) utilizing carbon isotopes (Cenomanian-Turonian transition) and two nannofossil datums from 'traditional' nannofossil schemes (E. rarus, M. furcatus). Calcareous nannofossil assemblages from Site 1260 show evidence for dynamic surface-water conditions in response to the global Oceanic Anoxic Event 2, most notably, a pronounced nannfossil assemblage shift from a Placozygus howei-dominated assemblage in the Upper Cenomanian to a Zeugrhabodtus moulladei-dominated assemblage in the lowermost Turonian. The acme of Zeugrhabdotus moulladei at the onset of OAE 2 supports evidence for an increase in surface-water paleoproductivity during this anoxic event. This study also examines four Turonian nannofossil lineages: Stoverius-Cylindralithus, Radiolithus-Eprolithus-Lithastrinus, Quadrum, and Rhomboaster-Liliasterites-Marthasterites. Three of these lineages show gradation between evolving genera, a phenomenon not commonly observed in calcareous nannofossils. Evidence of iterative evolution was shown in the Turonian Rhomboaster-Liliasterites-Marthasterites lineage, equivalent to the evolutionary history of the Paleogene Rhomboaster-Tribrachiatus lineage. Nine new species of calcareous nannofossils are described from these lineages: 'Cylindralithus' antarius, Liliasterites arkellii, Liliasterites salfeldii, 'Lithastrinus' novenarius, Quadrum kathetos, Quadrum trikathetos, Quadrum dodrans, Quadrum tricuspis, and Rhomboaster demerarensis. These forms evolved during a transition from compact, dense nannofossil morphotypes to elongated, sleeker nannofossil morphotypes, possibly in response to changing paleoceanographic conditions during two brief cooling intervals in the Middle Turonian.
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Date Issued: 2011
Identifier: FSU_migr_etd-7099
Format: Thesis

Title: Calcareous Nannoplankton as Paleoceanographic and Biostratigraphic Proxies: Examples from the Mid-Cretaceous Equatorial Atlantic (ODP Leg 207) and Pleistocene of the Antarctic Peninsula (NBP0602A) and North Atlantic (IODP Exp. 306).
Creator: Kulhanek, Denise Kay, Wise, Sherwood W., Froelich, Philip N., Parker, William C., Wang, Yang, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: This dissertation is a collection of three projects utilizing calcareous nannoplankton as biostratigraphic and paleoceanographic indicators. The materials studied come from three locations: 1) Ocean Drilling Program (ODP) Leg 207 (Site 1258) on Demerara Rise; 2) SHALDRIL II Cruise NBP0602A (Site 9) in the James Ross Basin, Western Weddell Sea; and 3) Integrated Ocean Drilling Program (IODP) Expedition 306 (Site U1313) in the North Atlantic. After an introductory chapter, Chapter 2 details the...
Show moreThis dissertation is a collection of three projects utilizing calcareous nannoplankton as biostratigraphic and paleoceanographic indicators. The materials studied come from three locations: 1) Ocean Drilling Program (ODP) Leg 207 (Site 1258) on Demerara Rise; 2) SHALDRIL II Cruise NBP0602A (Site 9) in the James Ross Basin, Western Weddell Sea; and 3) Integrated Ocean Drilling Program (IODP) Expedition 306 (Site U1313) in the North Atlantic. After an introductory chapter, Chapter 2 details the results from Site 1258, drilled during ODP Leg 207 on Demerara Rise off the northern coast of South America. This cruise recovered organic-rich Albian sediments that contain abundant, moderately to well preserved calcareous nannofossils. Biostratigraphic analysis shows the section primarily spans Roth's (1978) middle to late Albian Zone NC9. An unconformity separates these sediments from overlying uppermost Albian laminated shales from Zone NC10. The presence of Seribiscutum primitivum within the Albian section represents the first known occurrences of this species at such low latitudes, as Demerara Rise was located within 15º of the equator during the mid-Cretaceous. This species exhibits a bipolar distribution and is considered a cool-water, high-latitude species. Its presence on Demerara Rise indicates cooler water incursions either through changes in surface circulation or upwelling conditions during the opening of the Equatorial Atlantic. Chapter 3 details the results of a study of calcareous nannofossils in clasts obtained during the SHALDRIL II NBP0602A cruise to the Antarctic Peninsula. Site NBP0602A-9, drilled during the SHALDRIL II cruise of the RV/IB Nathaniel B. Palmer, includes two holes located in the northern James Ross Basin in the western Weddell Sea, very close to the eastern margin of the Antarctic Peninsula. Sediment from both holes consists of very dark grey, pebbly, sandy mud, grading to very dark greenish grey, pebbly, silty mud in the lower 2.5 m of the second hole. In addition to abundant pebbles found throughout the cores, both holes contain numerous sedimentary clasts. Biostratigraphic analysis of diatom assemblages from the glaciomarine muds yielded rare to few, poorly preserved diatoms that suggest the sediment is late Pleistocene in age. The sedimentary clasts, on the other hand, are nearly barren of diatoms, but contain rare, moderately to well preserved calcareous nannofossils. The clasts contain three distinct assemblages. Two clasts are assigned an early Maastrichtian age based on the presence of Biscutum magnum and Nephrolithus corystus, whereas one clast is of late Maastrichtian age based on the presence of Nephrolithus frequens. These samples also contain other characteristic Late Cretaceous species, including Biscutum notaculum, Cribrosphaerella daniae, Eiffellithus gorkae, Kamptnerius magnificus, and Prediscosphaera bukryi. Two samples contain an early Paleocene assemblage dominated by Hornibrookina teuriensis. The Maastrichtian assemblages are similar to those found in the López de Bertodano Formation on Seymour and Snow Hill Islands, making it the likely source area for the Cretaceous clast material. Although no calcareous nannofossils have been reported from Paleocene formations on these islands, the occurrence of calcareous foraminifers suggests other calcareous plankton may be present; thus, the Paleocene clasts likely also originated from the Seymour Island area. The fourth chapter presents results from a Pleistocene study of calcareous nannoplankton assemblages spanning 480-355 ka at IODP Site U1313. This site was a reoccupation of Deep Sea Drilling Project Site 607, drilled on the western flank of the Mid-Atlantic Ridge. This location is near the region of steepest sea-surface temperature gradients during the last glacial maximum, and is also on the southern margin of the ice-rafted debris (IRD) belt, making it an ideal location to study paleoclimate. Calcareous nannoplankton assemblages from Marine Isotope Stage (MIS) 12-10 record changes in surface-water conditions over this interval. The assemblage is dominated by family Noelaerhabdaceae, and spans a single biostratigraphic event, the last occurrence of Pseudoemiliania, dated to 427 ka at this site. Most species indicate paleoecological preferences similar to those found in the literature, although Gephyrocapsa oceanica is more abundant during MIS 12, even though it is thought to prefer warmer waters. Similarly, Helicosphaera, another warm-water taxon, is also more abundant during MIS 12. Both prefer higher nutrient conditions that occur during the glacial stage. The first factor of a CABFAC factor analysis explained nearly 92% of the variability in the assemblage. This factor is dominated by G. oceanica, and the varimax factor scores correlate well with the alkenone-based temperature record, suggesting that the distribution of G. oceanica at Site U1313 is controlled by temperature. The N ratio, based on the ratio of lower photic zone dweller Florisphaera profunda to upwelling indicators, shows deep stratification during much of MIS 12, usually associated with an increase in IRD and freshwater proxies indicating the presence of icebergs in the area. Finally, most productivity indicators suggest higher productivity during MIS 12, in contrast to the nannofossil accumulation rate (NAR), which was lower during that time. Other phytoplankton groups may have increased productivity during MIS 12, although further work is needed to explain why the abundance of alkenones indicates higher productivity in the calcareous nannoplankton when the NAR does not.
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Date Issued: 2009
Identifier: FSU_migr_etd-2965
Format: Thesis

Title: Carbon Exchange Variability over Amazon Basin Using Coupled Hydrometeorological-Mixed Layer PBL-CO2 Assimilation Modeling System Forced by Satellite-Derived Surface Radiation & Precipitation.
Creator: Grose, Andrew, Smith, Eric A., Ruscher, Paul H., Elsner, James B., Fuelberg, Henry E., Clayson, Carol A., Department of Earth, Ocean and Atmospheric Sciences, Florida State...
Show moreGrose, Andrew, Smith, Eric A., Ruscher, Paul H., Elsner, James B., Fuelberg, Henry E., Clayson, Carol A., Department of Earth, Ocean and Atmospheric Sciences, Florida State University
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Abstract/Description: With the aid of a 3-part modeling system forced by various satellite-remote sensed atmospheric inputs controlled by cloudiness, this study: (1) describes the space-time variations of surface net CO2 flux exchange over the large scale Amazon basin, (2) determines the key factors controlling these variations, and ultimately (3) determines the optimal spatial configuration of a network of tower observing posts, which if deployed, could capture in area-wide averages the main variant properties of...
Show moreWith the aid of a 3-part modeling system forced by various satellite-remote sensed atmospheric inputs controlled by cloudiness, this study: (1) describes the space-time variations of surface net CO2 flux exchange over the large scale Amazon basin, (2) determines the key factors controlling these variations, and ultimately (3) determines the optimal spatial configuration of a network of tower observing posts, which if deployed, could capture in area-wide averages the main variant properties of the Amazon basin's surface net carbon flux on an absolute basis. The philosophy guiding this research is that whereas a sufficiently detailed model can do very well in capturing the space-time gradients of carbon flux exchange and thus the relative source-sink properties of the Amazonian landscape, current modeling knowledge does not allow an adequate model determination of absolute source-sink properties. Direct observations are needed to obtain meaningful absolute accuracies of the source-sink properties, properties that are highly sensitive to environmental and bio-physiological factors that effectively produce a heterogeneous fabric of source and sink magnitudes across the basin at any given instant of time. However, for the Amazon basin, and as a general rule of thumb in carbon budget monitoring over a large expanse, there seems to be never enough observation posts to eliminate the systematic bias problem -- nor are those that do exist sited according to a network strategy that optimizes their collective ability to eliminate such a bias problem. A hydrometeorological model coupled to a mixed layer (ML) model of the planetary boundary layer (PBL) then equipped with a set of three CO2 assimilation models, and finally forced by high resolution satellite-retrieved incoming surface radiation fluxes and rainfall, forms a detailed carbon flux exchange modeling system linked to satellite inputs, that achieves the desired research objectives. The forcing of the model by remotely sensed solar/infrared radiative flux and rainrate variables, which exert dominant influences on the surface carbon budget and whose variant properties are determined by the position and diurnal timing of cloudiness, is an essential element of the modeling system. This is because one of the greatest shortcomings in prognostic modeling is the ability to reproduce real clouds, particularly convective clouds, in the right place at the right time. In understanding how environmental and bio-physiological factors exert their respective controls on carbon flux exchange variability, the underlying variables are classified into four categories: (1) meteorological factors; (2) radiation factors; (3) water cycle factors; and (4) bio-physiological factors. The three different CO2 assimilation models are investigated to achieve optimal performance insofar as obtaining validated surface carbon, heat, and moisture fluxes in the framework of the Florida State University (FSU) hydrometeorological model -- developed over the last decade by E.A. Smith & H.J. Cooper. Of the three carbon models examined, the one selected for the final net CO2 flux calculations was developed by G. Bonan, beginning with his Ph.D. dissertation research and now included in a land surface model (LSM) facility at NCAR. This carbon scheme contains a respiration component consistent with its photosynthetic component and physically couples the CO2, sensible, and latent heat fluxes through stomatal resistance. Test calculations of net ecosystem productivity (NEP) show that it is essential to model canopy-boundary layer interactions in order to reproduce observed morning CO2 effluxes measured at various forest sites located within Brazil and operated as part of the Large Scale Biosphere-Atmosphere Research Programme for Amazônia (LBA) -- specifically the LBA tower sites at Manaus and Jaru. This is because under typical conditions of a stable nocturnal PBL, the forest canopy remains stagnant, allowing carbon concentrations to become elevated until after sunrise when PBL stability flips and CO2 is rapidly vented into the atmosphere. In the PBL model developed for the study, CO2 concentrations and the concomitant fluxes are determined for five layers in and above the forest canopy following the progression of the ML during the daytime and the nocturnal boundary layer at night, which are treated as separate components of the diurnal PBL. It is important to point out that canopy heat capacity must be accounted for in the hydrometeorological modeling (an oft-overlooked factor in LSM modeling), to prevent sensible heat fluxes from being systematically overestimated. Values of observed canopy heat storage (needed in the development of the heat capacity scheme) are found using observed differences between net incoming radiation and sensible-latent heat fluxes, or observed total residual energy. Calibration and validation of CO2, sensible, and latent fluxes at the three LBA tower sites are accomplished using modeled total residual energy at the forest sites and modified photosynthesis parameters at the pasture site. Application of the modeling system over the large-scale Amazon basin shows that while vegetation type is the most important factor controlling area-wide CO2 fluxes, incoming surface solar radiation and ambient temperature (both directly responsive to the cloud field) are the primary factors producing spatial and temporal variability of CO2 fluxes at a given location. Modeled CO2 fluxes show mean monthly uptake values in the range of 1-3 mmol m-2 s-1. Due to the superimposed annual and daily march of the solar elevation angle, diurnal progressions of large coherent expanses of CO2 efflux over forest areas, progressing from SE to NW in December and from NE to SW in June, are an essential variational mode in the surface carbon budget. Inspection of area-wide modeled fluxes near the tower sites reveals that the systematic use of ECMWF-analyzed winds and temperatures in forcing the modeling system creates instances of spurious nocturnal stability that produce larger morning efflux magnitudes than observations suggest. Finally, CO2 fluxes at some 20,000 forest grid points within the Amazônia region and for eight months of model output, are analyzed to determine the optimal sampling configuration vis-à-vis capturing in area-wide averages, the space-time variability of net CO2 flux. These results lead to the conclusion that flux observations from five strategically placed towers, measuring in conjunction with the existing three LBA towers at Manaus and Jaru, would be sufficient in baselining area-wide net CO2 fluxes needed for an understanding of carbon sequestration within the Amazon basin on an absolute scale.
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Date Issued: 2004
Identifier: FSU_migr_etd-3949
Format: Thesis

Title: Characteristics and GFS Forecast Accuracy of Intraseasonal Shifts in the Arctic Oscillation Index.
Creator: Visco, Travis Connor, Fuelberg, Henry E., Hart, Robert E., Sura, Philip, Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: 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...
Show moreThis 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.
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Date Issued: 2012
Identifier: FSU_migr_etd-5453
Format: Thesis

Title: Characteristics of Decaying Storms during Lightning Cessation at Kennedy Space Center and Cape Canaveral Air Force Station.
Creator: Anderson, Holly Alison, Fuelberg, Henry E., Ruscher, Paul H., Hart, Robert E., Department of Earth, Ocean and Atmospheric Sciences, Florida State University
Abstract/Description: Improved knowledge of thunderstorm behavior near the end of its lifecycle is essential to improving the prediction of lightning cessation. This study documents the characteristics of decaying storms near the end of their lightning activity at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). Total lightning data were obtained by combining information from the Lightning Detection and Ranging (LDAR) network with the Cloud-to-Ground-Surveillance System (CGLSS) and the...
Show moreImproved knowledge of thunderstorm behavior near the end of its lifecycle is essential to improving the prediction of lightning cessation. This study documents the characteristics of decaying storms near the end of their lightning activity at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). Total lightning data were obtained by combining information from the Lightning Detection and Ranging (LDAR) network with the Cloud-to-Ground-Surveillance System (CGLSS) and the National Lightning Detection Network (NLDN). The lightning data were used in conjunction with WSR-88D radar data and Rapid Update Cycle (RUC) model analyses. The study focuses on a dataset of 116 isolated unicellular and multicellular storms during the warm-seasons (May-September) of 2000-2005. Twenty of the 116 storms were tracked through lightning cessation using the K-Means storm clustering and tracking algorithm within the Warning Decision Support System – Integrated Information (WDSS-II). This tracking yielded time-series of radar-derived, RUC-derived, and lightning parameters. Flash characteristics of the 116 storms showed trends during storm growth and dissipation; however, none exhibited clear relationships with the final flash. Although most storms experienced gradually decaying flash rates until cessation, two other cessation behaviors also were observed, making flash activity an unreliable indicator of cessation. Trends in composite reflectivity, reflectivity at three temperatures crucial to storm electrification (i.e., 0°C, -10°C, -20°C), storm thickness of 30 dBZ above -10°C, and vertical gradients of reflectivity were analyzed for 20 storms during the 8 min period prior to cessation to determine if any indicated imminent cessation. Results showed substantial variability in the decaying storms. Although these parameters decreased in most storms during the 8 min period, some increased. Distributions of the parameters at the last flash also were considered, but no clearly preferred value was evident at the last flash. Neither the inversion of lightning initiation criteria (e.g., 40 dBZ at -10°C) nor the descent of 45 dBZ below -10°C were found to be a useful indicator of cessation. Previously-documented lightning "bubbles" of LDAR sources were observed and were consistent with pulses in the intensifying updrafts. The last lightning "bubble" signatures were found to precede lightning cessation by ~35 min.
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Date Issued: 2010
Identifier: FSU_migr_etd-0197
Format: Thesis

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