Physical Sciences and Mathematics Commons^™

On The Frontlines - The Fishermen Of Ibrahim Hyderi, Muhammad Haris Aslam Khan

MSJ Capstone Projects

Climate change has become a matter of recent debate for much of the world. According to a report published by a German watch, a non-governmental organization, in 2019, Pakistan among the five countries at severe risk of climate change disasters.

During the last two decades, Pakistan saw more than 141 extreme climatic catastrophes. Only in 2016, more than 566 people died due to these conditions.

A report published by Asian Development Bank in 2017 indicates Pakistan’s climate change profile. It states that more than 1,600 people have lost their lives in the super flood of 2010 alone. A loss of …

Past Climate And Sea-Level Reconstruction Using Cave Deposits From Mallorca, Spain, Oana-Alexandra Dumitru

USF Tampa Graduate Theses and Dissertations

The potential impacts of the increasing temperature on the water resources, as well as the hazards associated with the sea-level rise in the low-elevation coastal zones of the Mediterranean Sea, makes this region vulnerable to current climate change due to global warming. Hence, accurate projections of the future hydroclimate scenarios in this area are crucial. Long-term information on climate and sea-level variability cannot be obtained by direct observations or using short instrumental records. However, various geological archives may provide valuable data that can be then used to assess the models used for future predictions.

This thesis presents results on past …

Comparative Assessment Of Downscaling Methods And Application Towards Analysis Of Climate Change Impact On Urban Regions, Markus Eichenbaum

Electronic Thesis and Dissertation Repository

Global climate models (GCM) are sophisticated numerical models used to make long term climate projections. However, the resolution of their output is too coarse for climate change related local impact studies on urban regional scales. Downscaling efforts are taken to address this and increase GCM projection resolution. Physical Scaling (SP) downscaling methodology attempts to incorporate the physical basis of dynamical downscaling efforts with the computational efficiency of statistical methods. In this study, North American Regional Reanalysis surface skin temperature and precipitation data for a 1°x1° region centered on Houston, TX are downscaled to a resolution of 500m via SP and …

A Numerical Investigation Of Sediment Dynamics In The Northern Gulf Of Mexico In Connection With Hurricanes, Fluid Mud, Climate Change, And Biogeochemical Cycling, Zhengchen Zang

LSU Doctoral Dissertations

Sediment transport and deposition in marginal seas is jointly controlled by many factors including hydrodynamics, fluvial inputs, and the characteristics of sediment particles. This dissertation study employs the coupled ocean-atmosphere-wave-and-sediment transport modeling system (COAWST) to investigate the mechanism of sediment transport in the northern Gulf of Mexico (nGoM) on different temporal scales, as well as its interaction with biogeochemical processes.

First of all, a three-way coupled (atmosphere-wave-ocean) hurricane model reproduced the hydro- and sediment dynamics during hurricane Gustav (2008). Intensive alongshore and offshore currents were simulated on the eastern/western sectors of hurricane track, respectively. High suspended sediment concentration (SSC) was …

Spatiotemporal Downscaling Rainfall Predictions Of North American Regional Climate Change Assessment Program For Entire Virginia, Zhaoyi Cai

Civil & Environmental Engineering Theses & Dissertations

This thesis developed a statistical downscaling approach, which consists of a series of linear regression equations, to spatiotemporally downscale the rainfall predictions from North American Regional Climate Change Assessment Program (NARCCAP) in accordance with the 15-min observed rainfall data at the rain gauges across the state of Virginia. NARCCAP has generated twelve different region-global climate models (RCM-GCMs) with a temporal resolution of 3 hr and a spatial resolution of 50 km over the entire America. Although it has been downscaled already, such resolutions are still too coarse to represent the rain gauges. This means that the RCM-GCMs’ predictions need to …

The Stability Of Temperate Lakes Under The Changing Climate, Aleksey Paltsev

Electronic Thesis and Dissertation Repository

There is a collective prediction among ecologists that climate change will enhance phytoplankton biomass in temperate lakes. Yet there is noteworthy variation in the structure and regulating functions of lakes to make this statement challengeable and, perhaps, inaccurate. To generate a common understanding on the trophic transition of lakes, I examined the interactive effects of climate change and landscape properties on phytoplankton biomass in 12,644 lakes located in relatively intact forested landscapes. Chlorophyll-a (Chl-a) concentration was used as a proxy for phytoplankton biomass. Chl-a concentration was obtained via analyzing Landsat satellite imagery data over a 28-year period (1984-2011) and using …

Abrupt Climate Transitions, Christine J. Ramadhin

Dissertations, Theses, and Capstone Projects

The Earth’s climate system displays a long history of nonlinear abrupt transitions which have resulted in significant ecosystem disruption and are recorded in the geologic data. Today significant anthropogenic changes are occurring in many Earth systems that seem to be pushing these toward critical thresholds. Thus, increasing the possibility of a transition to alternative states which can have unfavorable consequences. Therefore, it becomes compelling to forecast when and how these transitions will occur so that decision-makers can devise appropriate strategies to avoid or cope with the effects of a changeover to a new alternative state. However, due to the highly …

Wind Flow Dynamics Over Complex Terrain, Eric Kutter

Dissertations, Theses, and Capstone Projects

Understanding the exchange of energy, moisture, and trace gases between the terrestrial biosphere and the atmosphere over complex terrain is a fundamental goal in achieving a complete model of global or regional climate. Net ecosystem exchange (NEE) of carbon dioxide is often a crucial input into climate models, and is also used as a means of validating regional model outputs. Calculations obtained from eddy flux tower data provide some of the best quality sources of NEE values; however, the standard formulation of the eddy covariance method is incomplete in terrain that includes common features such as hills, forests, cities, or …

Mechanisms Of Ice Core Stable Isotope Variability In The Upper Kaskawulsh-Donjek Region, St. Elias Mountains, Yukon, Canada, Erin A. Mcconnell

Electronic Theses and Dissertations

I use instrumental and ice core records to examine drivers of observed isotope variability in the Upper Kaskawulsh-Donjek (UKD) region of the St. Elias Mountains, Yukon, Canada over the time frame of instrument-proxy overlap (mid-1900s to present). One of the drivers of post-depositional isotope signal alteration is the vertical percolation of meltwater from the glacier surface through shallow layers of snow, which causes a reduction in the amplitude of the isotope signal recorded in ice cores. I examine isotope signal preservation in two sites in the St. Elias Mountains: Eclipse Icefield and Icefield Divide. These sites are relatively close (~30 …

A Tale Of Two Bays: The Development And Applications Of The Saco And Casco Modeling Project, Stephen M. Moore

Electronic Theses and Dissertations

This thesis details the development and application of a finite-volume, hydrodynamic model of Saco and Casco Bays. The primary study conducted herein focused on coupling storm simulations with sea level rise (SLR) to identify vulnerabilities of the two bays. The February 1978 Northeaster and an April freshwater discharge event in 2007 following the Patriot’s Day Storm were modeled by utilizing the Finite-Volume Coastal Ocean Model (FVCOM). Both events were repeatedly simulated under SLR scenarios ranging from 0 to 7 ft. Modeled storm responses were identified from the 1978 blizzard simulations and were tracked across SLR scenarios. By comparing changes in …

Toward Improved Understanding Of Black And Brown Carbon Radiative Impacts Over South Asia, Apoorva Pandey

McKelvey School of Engineering Theses & Dissertations

Atmospheric aerosols directly affect the Earth’s radiative budget by absorbing and scattering solar radiation. Carbonaceous aerosols constitute 20-90% of the global aerosol mass burden and are recognized by the Intergovernmental Panel on Climate Change as important drivers of direct radiative forcing (DRF). Aerosol radiative impacts have been implicated in regional atmospheric warming in South Asia: changing Indian monsoon patterns, and accelerating melting of the Himalayan glaciers. There are systematic global discrepancies between estimates of aerosol absorption optical depths derived from observations and those from climate models. Over South Asia, models predict six times lower aerosol absorption than ground-based observations, leading …

Sedimentological And Geochemical Analysis Of Deep-Water Deposits In The Mojón De Hierro Formation At Arroyo Garrido, Tepuel-Genoa Basin, Patagonia, Argentina, Natalie Beatrice Mcnall

Theses and Dissertations

The Earth has had multiple Phanerozoic glacial intervals but the Late Paleozoic Ice Age (LPIA) was its longest and most extensive, lasting from the Late Devonian (~372 Ma) until the Late Permian (~254 Ma). The LPIA is the last complete climate shift from a greenhouse to icehouse and back to a greenhouse state and the only one to occur on a biologically complex Earth. Therefore, it provides perspectives on deep-time climatic transitions, the parameters controlling them, and the Earth’s physical, chemical and biological responses to such climate changes. Research on mid to high-latitude deposits in Gondwana provides evidence that the …

Change In The Leading Mode Of North America's Wintertime Stationary Eddies, Yu-Tang Chien

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Extreme winter weather events in North America have become more frequent and increasingly destructive. This phenomenon was linked to a jet stream pattern that generates abnormally warm conditions in the west and cold conditions in the east, referred to as the North American Winter Dipole. Studies have shown that the Dipole may have amplified and this amplification could be linked to global warming. By analyzing the atmospheric and oceanic data worldwide, the wintertime circulation in the Northern Hemisphere shows signs of a persistent change after the 1980s. In the first part of this study, we examine how the ocean has …

Intermittent Turbulent Exchanges And Their Role In Vineyard Evapotranspiration, Sebastian Alexander Los

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Vineyards are often grown in semi-arid climates, such as California’s central valley, where water resources can be limited. Summer weather conditions result in high water use by these plants. For wine grapes, a high-value commodity, there are known benefits to fruit quality in irrigating grapevines with slightly below optimum for the plant. Growers would like to be able to precisely irrigate without overusing water or overstressing the vines. This calls for improving ways to monitor vineyard water use by estimating the combined soil evaporation and plant transpiration known as evapotranspiration (ET). A computer model developed by the USDA called the …

Spatio-Temporal Analysis Of Tree Ring Chronology And Precipitation, Ruizhe Yin

Graduate Theses and Dissertations

Tree ring chronology data is known to reflect regional climate due to the strong impact of rainfall and temperature. Therefore, tree ring data can be used to reconstruct historical climate in order to understand how climate changed in the past and make prediction about the future behavior of the climate. For simplicity, this research only considers the influence of precipitation on tree ring growth within the New England area. A total of 94 measurement sites are used to record tree ring width over 881 years and corresponding precipitation data are given at some locations for 121 years. We developed a …

A Tropospheric Water Vapour Climatology And Trends Derived From Vibrational Raman Lidar Measurements Over Switzerland, Shannon Hicks-Jalali

Electronic Thesis and Dissertation Repository

Water vapour is the most effective atmospheric greenhouse gas in terms of warming the atmosphere. Water vapour can magnify the temperature increase that CO₂ would cause alone by 2-3 times. As such, it is critical to monitor changes in water vapour abundance to better understand its role in atmospheric change. I have used 10 years of lidar and radiosonde measurements from the MeteoSwiss research station in Payerne, Switzerland to calibrate the lidar, improve its water vapour retrievals, and finally calculate a lidar water vapour climatology and trend analysis.

Calculating trends with a lidar requires rigorous calibration. Therefore, my first …

An Estimation Of Lower Tropospheric Mixing Derived From Inverse Modeling Of Boundary Layer Water Vapor Isotopologues On Graciosa Island, Azores, Jacquelyn M. Delp

Earth and Planetary Sciences ETDs

Recent studies have shown water vapor isotopologues to be sensitive tracers of mixing processes that govern low-cloud feedback in climate models. In this study, we develop an inverse model (MBL Mix inverse model) that uses one year of isotope and humidity observations from Graciosa Island, Azores to estimate mixing for four seasons. We show the dry end-member of the model, the lower free troposphere (LFT), can be represented using Rayleigh fractionation. Isotope observations from Graciosa Island are compared to other field locations to discuss controls on isotopic variability other than mixing. Output from the MBL Mix inverse model shows the …

Evaluating Future Reservoir Storage In The Rio Grande Using Normalized Climate Projections And A Water Balance Model, Nolan T. Townsend

Earth and Planetary Sciences ETDs

We develop and implement new tools for assessing the future of surface water supplies in downstream reaches of the Rio Grande, for which Elephant Butte Reservoir is the major storage reservoir. First, a normalization procedure is developed to adjust natural Rio Grande streamflows simulated by dynamical models in downstream reaches. The normalization accounts for upstream anthropogenic impairments to flow that are not considered in the model, thereby yielding downstream flows closer to observed values and more appropriate for use in assessments of future flows in downstream reaches. The normalization is applied to assess the potential effects of climate change on …

An Estimation Of Lower Tropospheric Mixing Derived From Inverse Modeling Of Boundary Layer Water Vapor Isotopologues On Graciosa Island, Azores, Jacquelyn M. Delp

Earth and Planetary Sciences ETDs

Recent studies have shown water vapor isotopologues to be sensitive tracers of mixing processes that govern low-cloud feedback in climate models. In this study, we develop an inverse model (MBL Mix inverse model) that uses one year of isotope and humidity observations from Graciosa Island, Azores to estimate mixing for four seasons. We show the dry end-member of the model, the lower free troposphere (LFT), can be represented using Rayleigh fractionation. Isotope observations from Graciosa Island are compared to other field locations to discuss controls on isotopic variability other than mixing. Output from the MBL Mix inverse model shows the …

Sources And Chemical Stability Of Soil Organic Carbon Along A Salinity Gradient And A Chronosequence Of Created Brackish Marshes In Coastal Louisiana, Megan L. Kelsall

LSU Master's Theses

Tidal marshes have been recognized for providing a number of important ecological services including soil carbon sequestration. However, the loss of tidal marsh habitat due to climate change and anthropogenic stressors exposes previously stored soil organic carbon (SOC) to oxidation. The vulnerability of SOC to oxidation depends on its chemical stability and environmental conditions limiting decomposition. Labile organic carbon (LC), decomposes quickly unless abiotic conditions limit decomposition. Recalcitrant organic carbon (RC) decomposes slower and is stored for longer time periods. Predicting long-term storage of SOC is complicated by the potential for multiple SOC sources, differences in chemical stability, and variation …

The Evolution Of The El Niño-Southern Oscillation And Tropical Pacific Climate Across The Last Deglaciation, Ryan Hunter Glaubke

OES Theses and Dissertations

The El Niño – Southern Oscillation (ENSO) is the largest interannual component of Earth’s climate system, capable of exerting significant influence over global climate patterns that affect communities around the globe. Nevertheless, a comprehensive understanding of the ENSO system and its relationship to tropical Pacific climate dynamics remains unclear. Although new paleoceanographic proxies have shown promise in in their ability to constrain past ENSO change, little is known about how ENSO varied in response to millennial-scale climate events over the last 25,000 years. Here, I present new records of tropical Pacific mean state and ENSO variability over the last 25,000 …

Hourly Precipitation Climatology Of The Southeast United States, Vincent Brown

LSU Doctoral Dissertations

Precipitation changes are one of the most important potential outcomes of a warming climate because of how essential it is to society and ecosystems. Sub-daily precipitation time series provide more information on precipitation characteristics, particularly frequency, intensity, and duration compared to daily data. In a series of four peer-reviewed manuscripts, this research investigates sub-daily precipitation characteristics from a climatological perspective. The first study introduces a climatology of hourly precipitation for four first-order weather stations across Louisiana, explores possible changes in the hourly precipitation distribution, and links winter Gulf of Mexico sea surface temperatures to the frequency of hours with precipitation. …

Spatiotemporal Impact Of Snow On Underwater Photosynthetically Active Radiation In Taylor Valley, East Antarctica, Madeline E. Myers

LSU Master's Theses

The role of snow on underwater photosynthetically active radiation (UW PAR) in the McMurdo Dry Valleys (MDVs) has been understudied due to lack of a detailed snowfall record. Research has shown that a relationship between snow cover and UW PAR exists, but the extent has never been evaluated in great detail. Although annual snowfall values in the MDVs are low (3 to 50 mm water equivalent annually), trends of increasing snowfall on the continent under future warming conditions could lead to an increased role for snow in regulating UW PAR (and associated primary productivity). Here, I discuss evidence from the …

The Long-Run Effects Of Tropical Cyclones On Infant Mortality, Isabel Miranda

Master's Theses

In the United States alone, each tropical cyclone causes an average of $14.6 billion worth of damages. In addition to the destruction of physical infrastructure, natural disasters also negatively impact human capital formation. These losses are often more difficult to observe, and therefore, are over looked when quantifying the true costs of natural disasters. One particular effect is an increase in infant mortality rates, an important indicator of a country’s general socioeconomic level. This paper utilizes a model created by Anttila-Hughes and Hsiang, that takes advantage of annual variation in tropical cyclones using annual spatial average maximum wind speeds and …

Blacklegged Tick (Ixodes Scapularis) Distribution In Maine, Usa, As Related To Climate Change, White-Tailed Deer, And The Landscape, Susan P. Elias

Electronic Theses and Dissertations

Lyme disease is caused by the bacterial spirochete Borrelia burgdorferi, which is transmitted through the bite of an infected blacklegged (deer) tick (Ixodes scapularis). Geographic invasion of I. scapularis in North America has been attributed to causes including 20th century reforestation and suburbanization, burgeoning populations of the white-tailed deer (Odocoileus virginianus) which is the primary reproductive host of I. scapularis, tick-associated non-native plant invasions, and climate change. Maine, USA, is a high Lyme disease incidence state, with a history of increasing I. scapularis abundance and northward range expansion. This thesis addresses the question: “To …

Climate-Driven Migration: Prioritizing Cultural Resources Threatened By Secondary Impacts Of Climate Change, Frankie St. Amand

Electronic Theses and Dissertations

Archaeological sites suffer increasingly destructive primary impacts of climate-driven natural hazards, including sea level rise, flooding, and erosion. Action is generally limited to mitigation and salvage of immediately threatened sites, with little attention or forethought given to secondary effects, such as destruction of interior archaeological resources by inland migration of affected populations. The United Nations predicts a growing trend in resettlement of climate-affected communities from areas where in-situ infrastructure adaptations are not economically feasible, legal, or physically possible. While adapting existing urban infrastructure (e.g., abating combined sewage overflows) is a viable option in the primary impact zone (e.g. coastal areas …

A 2000 Year Saharan Dust Event Record From A European Alps Ice Core, Heather Clifford

Electronic Theses and Dissertations

Ice core archives provide the most direct and detailed evidence of past climate and atmospheric conditions, however, traditional ice core sampling (~1-cm resolution) does not provide significant environmental detail in low accumulation and compressed ice core sites. Advances in ice core sampling techniques allows for the capability to detect environmental signals in compressed ice found deeper in the core using finer sampling resolutions. Using the Climate Change Institute’s W.M. Keck Laser Ice Facility non-destructive, ultra-high-resolution, continuously sampled laser ablation-inductively coupled plasma-mass spectrometer (LA-ICP-MS) sampling on ice cores, we are able to resolve proxies for both climatological and meteorological scale events …

A Multi-Proxy Paleoecological Reconstruction Of Holocene Climate, Vegetation, Fire And Human Activity In Jamaica, West Indies, Mario A. Williams

Electronic Theses and Dissertations

Jamaica is located in the Caribbean biodiversity hotspot and has a rich flora and fauna, most notably characterized by exceptional levels of plant endemism. These natural resources are imperiled by climate change and increasing anthropogenic pressures, therefore highlighting the importance of implementing effective conservation programs to mitigate ecosystem degradation. Paleoecological studies that investigate the diversity and distributions of organisms and their habitats over millennial timescales provide critical long-term spatial and temporal context for the assessment of contemporary environmental problems. Lake sediments are a highly useful archive for the study of prehistoric climate and ecological changes, as biological, chemical and geophysical …

Wish You Were Here, Janie Stamm, Janie I. Stamm

Graduate School of Art Theses

The State of Florida is under threat from the effects of climate change. Rising sea levels are creeping up on to Florida’s coast, eroding the beaches and encroaching on heavily populated cities. Over my lifetime I will watch the water spill over the streets of my home town. I will watch the water flood the Everglades, pushing saltwater into freshwater habitats. I will watch the water begin to drown the state, taking Florida’s many little known histories along with it. This thesis serves as a document of Floridian life during the Anthropocene.

Within this thesis, I tell the story of …

Daily To Seasonal Moisture Signals Present In Sub-Annual Tree-Ring Data, Ian Howard

Graduate Theses and Dissertations

In recent decades, there has been an increase in the development of sub-annual earlywood (EW) and latewood (LW) width tree-ring chronologies that have been used to make long-term inferences about discrete seasonal moisture variability for different regions of North America. This doctoral research developed a new network of EW, LW, and adjusted latewood (LWa) tree-ring chronologies from the western Great Plains. These chronologies were used to reconstruct 300+ years of spring and summer moisture variability over the northern and southern Plains. The reconstructions document new information about the long-term seasonal climate history of the Great Plains, including the unusual nature …