Climate Commons^™

Hydrodynamic Tipping Points In The Mississippi Sound In Response To Bonnet Carré Spillway Openings, Mustafa Kemal Cambazoglu, Brandy N. Armstrong, Mohsena Lopa, Marc Diard, Jerry D. Wiggert

Faculty Publications

This project examines the current operational strategy of the Bonnet Carré Spillway (BCS), a Mississippi River flood-control structure located about 21 miles northwest of New Orleans, Louisiana, and managed by the U.S. Army Corps of Engineers. The BCS is part of the larger Mississippi River and Tributaries Project, a network of levees and control structures designed to minimize flooding from the American plains to southern Louisiana. The spillway is opened when river discharge at New Orleans is forecasted to exceed 1,250,000 cubic feet per second, diverting significant volumes of Mississippi River water into Lake Pontchartrain which subsequently flows into Mississippi …

An Investigation Of Paleoclimate Through A Sedimentological Lens In The Gulf Of Mexico And Western North Pacific, Sarah Monica

Dissertations

This dissertation explores the use of sediment cores as proxy data for the reconstruction of paleoclimatic and environmental conditions. Human-caused climate change is leading to dramatic shifts in the global climate. As the instrumental record of climate is relatively short compared to the amount of time Earth has experienced weather, this work aims to extend our knowledge of climate beyond the instrumental record, thereby improving our holistic understanding of the climate system. In Chapter one, sediment cores from the central Texas inner shelf are used to produce a record of intense tropical cyclone (TC) activity over a ~4500-year period. X-Ray …

Sedimentary Characteristics Of Flood Deposits In Coastal And Fluvial Environments: Examples From Washover Fans (North Carolina, Usa) And Floodplain Deposits (Mississippi, Usa), Shara Gremillion

Dissertations

Extreme flooding from severe and prolonged meteorological events and / or overbanking rivers are some of the most deadly and expensive disasters globally, impacting millions of lives, the environment, and property. People living in vulnerable areas, such as near coasts and rivers, are the first to be impacted with effects of these flood hazards. Scientific studies and their results can aid communities and officials in planning and preparing for those flood impacts. In this three-part study, flood impacts from coastal storms in North Carolina, and flooding along the Mississippi River (MSR) in the state of Mississippi, USA are assessed from …

Investigating Nekton Response To Changing Salinities In The Mississippi Sound: An Experimental And Statistical Approach, Adam Murray

Master's Theses

The Mississippi Sound provides nursery habitats for many coastal species and is recognized for its commercial fisheries. Previous freshening events linked to the Bonnet Carré Spillway, a Mississippi River flood diversion structure, proved catastrophic for oyster populations in the Mississippi Sound, but effects on mobile fish and shellfish species are not well-defined. The planned Mid-Breton Sediment Diversion (MBSD), an initiative to combat wetland loss, is also forecasted to lower salinities in the region, increasing the need to better understand responses of commercially and ecologically important species to freshening events. The objective of this study was to characterize effects of salinity …

Modeling Hourly Storm Surges Using Deep Learning Techniques, Md Abu Zafor

Master's Theses

Storm surges cause coastal flooding, one of the most devastating coastal hazards. Accurate modeling of storm surges is essential for predicting and mitigating these impacts. Traditional approaches model surges at individual tide gauges and often focus on daily time scales, leading to data redundancy and limiting their ability to capture sub-daily variability. This study addresses these limitations using deep learning (DL) algorithms to model hourly surges simultaneously at multiple tide gauges along the U.S. East Coast and Gulf of Mexico. Three algorithms, Convolutional Neural Network (CNN), Long Short-Term Memory (LSTM), and a hybrid ConvLSTM are employed to model surges using …

Investigation Of Dead Ocean Quahogs (Arctica Islandica) Shells On The Mid-Atlantic Bight Continental Shelf, Alyssa Leclaire

Master's Theses

Ocean quahogs, Arctica islandica, are a long-lived, widely dispersed, biomass dominate in the Mid-Atlantic; therefore, quahog shells are valuable resources for studying climate change over time. Recently, dead ocean quahog shells were discovered south and inshore of the present biogeographic range of this animal. The presence of ocean quahog shells outside the current range is presumably a consequence of past regressions and transgressions of the Cold Pool, the bottom-trapped, cool body of water that allows boreal animals to live at lower latitudes. Dead ocean quahog shells were collected offshore of the DelMarVa Peninsula then radiocarbon-dated, evaluated for taphonomic condition, …

Analysis Of Fossil Pollen From A Pleistocene Cypress Forest Preserved On The Northern Gulf Of Mexico Continental Shelf, Kathryn Joyce Garretson

Master's Theses

This study presents the findings of fossil pollen analysis performed on terrestrial sediments preserved on the northern Gulf of Mexico continental shelf (site hereafter known as the Underwater Forest or DF). This research aims to establish vegetation composition on a continental shelf glacial refuge and provide a better understanding of vegetation response to sea-level rise. Two cores (15DF1 and 15DF3B) located at different locations within the forest were recovered and analyzed. Pollen results from both cores were similar, with high percentages of Taxodium and Nyssa pollen in the lowermost sections reflecting an assemblage typical of contemporary baldcypress swamps. Pollen assemblages …

Mid-Breton Sediment Diversion (Mbrsd) Assessment – Final Report, Jerry D. Wiggert, Brandy N. Armstrong, M. Kemal Cambazoglu, Sandeep Kalathupurath Kuttan

Faculty Publications

The purpose of this project is to provide managers at the Mississippi Department of Marine Resources (MDMR) with the scientific information needed to accurately address public concerns regarding the potential effects of the Louisiana Coastal Master Plan / Coastal Protection and Restoration Authority (CPRA) Mid-Breton Sediment Diversion (MBrSD) on the jurisdictional waters and resources of Mississippi. The stated design purpose of the MBrSD is to reconnect and re-establish the deltaic sediment deposition process between the Mississippi River and the Breton Sound Basin through a diversion that will deliver up to 75,000 cfs of sediment-laden freshwater. The report presented herein provides …

Heterogeneous Co2And Ch4Content Of Glacial Meltwater From The Greenland Ice Sheet And Implications For Subglacial Carbon Processes, Andrea J. Pain, Jonathan B. Martin, Ellen E. Martin, Åsa K. Rennermalm, Shaily Rahman

Faculty Publications

Accelerated melting of the Greenland Ice Sheet has increased freshwater delivery to the Arctic Ocean and amplified the need to understand the impact of Greenland Ice Sheet meltwater on Arctic greenhouse gas budgets. We evaluate subglacial discharge from the Greenland Ice Sheet for carbon dioxide (CO₂) and methane (CH₄) concentrations and δ¹³C values and use geochemical models to evaluate subglacial CH₄ and CO₂ sources and sinks. We compare discharge from southwest (a sub-catchment of the Isunnguata Glacier, sub-Isunnguata, and the Russell Glacier) and southern Greenland (Kiattut Sermiat). Meltwater CH₄ concentrations vary …

Sampling Density And Date Along With Species Selection Influence Spatial Representation Of Tree-Ring Reconstructions, Justin T. Maxwell, Grant L. Harley, Trevis J. Matheus, Brandon M. Strange, Kayla Van Aken, Tsun Fung Au, Joshua C. Bregy

Faculty Publications

© 2020 Royal Society of Chemistry. All rights reserved. Our understanding of the natural variability of hydroclimate before the instrumental period (ca. 1900 CE in the United States) is largely dependent on tree-ring-based reconstructions. Large-scale soil moisture reconstructions from a network of tree-ring chronologies have greatly improved our understanding of the spatial and temporal variability in hydroclimate conditions, particularly extremes of both drought and pluvial (wet) events. However, certain regions within these large-scale network reconstructions in the US are modeled by few tree-ring chronologies. Further, many of the chronologies currently publicly available on the International Tree-Ring Data Bank (ITRDB) were …

Utilizing Manganese And Rhenium Sediment Concentrations To Reconstruct Past Interglacial Southern Ocean Circulation Changes, Evan E. Rohde

Honors Theses

The circulation in the Southern Ocean is a component of global nutrient, heat, and carbon cycles. Changes in any of these cycles can dramatically change ocean conditions around the world. Therefore, any changes that occurred to this circulation in the past is of scientific interest. We hypothesize that changes in the glacial cycle of the planet can affect this circulation. Specifically, we hypothesize that the strength of circulation in the Southern Ocean can be reduced by conditions during interglacial, or warm climate, time periods. It is proposed that during the interglacial period of Marine Isotope Stage (MIS) 11 (425 to …

The Importance Of Infrequent, High-Intensity Rainfall Events For Longleaf Pine (Pinus Palustris Mill.) Radial Growth And Implications For Dendroclimatic Research, Tyler J. Mitchell, Paul A. Knapp, Thomas W. Patterson

Faculty Publications

Tree-ring based precipitation reconstructions are beneficial in placing interannual variability in an historical context. However, absent specificity on what is being modeled (e.g., event type or rainfall intensity), similar rainfall totals inferred from reconstructions between different years imply similar conditions. Consequently, variability in specific precipitation event types or intensity can affect radial growth widths despite no changes in overall precipitation amount. Here, we use a longleaf pine latewood chronology to demonstrate how infrequent, intense (i.e., > 2.0 SD above mean) rainfall events (IREs), representing ~ 50% of total summer (July–September) precipitation amounts and 14.1% of rainfall events, principally determine interannual variability …

Gulf Coast Marine Laboratories Past, Present And Future, Donald F. Boesch

Gulf and Caribbean Research

I spent my nearly 50—year career in marine science working at marine laboratories, most of that as a chief executive officer. So, it is appropriate that my reflections are about marine laboratories, rather than my own science. After relating my career course, I turn my attention to the history and development of marine laboratories along the U.S. coast of the Gulf of Mexico (GOM). Surprisingly, the region’s first laboratory was actually constructed in 1903 at Cameron, LA, but operated less than a decade before closing. It was not until after World War II that the university—affiliated marine laboratories of today …

A Sustained Ocean Observing System In The Indian Ocean For Climate Related Scientific Knowledge And Societal Needs, J.C. Hermes, Y. Masumoto, L.M. Beal, M.K. Roxy, J. Vialard, M. Andres, H. Annamalai, S. Behera, N. D'Adamo, T. Doi, M. Feng, W. Han, N. Hardman-Mountford, H. Hendon, R. Hood, S. Kido, C. Lee, T. Lee, M. Lengaigne, J. Li, R. Lumpkin, K.N. Navaneeth, B. Milligan, M.J. Mcphaden, M. Ravichandran, T. Shinoda, A. Singh, B. Sloyan, P.G. Strutton, A.C. Subramanian, S. Thurston, T. Tozuka, C.C. Ummenhofer, A.S. Unnikrishnan, R. Venkatesan, D. Wang, J. Wiggert, L. Yu, W. Yu

Faculty Publications

The Indian Ocean is warming faster than any of the global oceans and its climate is uniquely driven by the presence of a landmass at low latitudes, which causes monsoonal winds and reversing currents. The food, water, and energy security in the Indian Ocean rim countries and islands are intrinsically tied to its climate, with marine environmental goods and services, as well as trade within the basin, underpinning their economies. Hence, there are a range of societal needs for Indian Ocean observation arising from the influence of regional phenomena and climate change on, for instance, marine ecosystems, monsoon rains, and …

A Multi-Millennial Drought Reconstruction For West-Central New Mexico Using Rocky Mountain Juniper (Juniperus Scopulorum, Sarg.), Joshua S. Oliver

Master's Theses

A new multi-millennial tree-ring record from living and remnant Rocky Mountain juniper (Juniperus scopulorum, Sarg.) wood from Candelaria in west-central New Mexico is used to determine the temporal and spatial variability of scPDSI over the past two millennia (B.C. 492 to A.D. 2014). Our record indicates extreme drought events found within other hydroclimatic proxy records in the Colorado Plateau region spanning the time period (16^th century and 2^nd century megadroughts). By ranking the extreme drought events by magnitude, duration, intensity, and overall score, the most extreme drought events of this record are compared to drought events …

Determining The Viability Of Recent Storms As Modern Analogues For North-Central Gulf Of Mexico Paleotempestology Through Sedimentary Analysis And Storm Surge Reconstruction, Joshua Caleb Bregy

Master's Theses

The northern Gulf of Mexico has been devastated by recent intense storms. Camille (1969) and Katrina (2005) are two notable hurricanes that made landfall in virtually the same location in Mississippi. However, fully understanding the risks and processes associated with hurricane impacts is impeded by a short and fragmented instrumental record. Paleotempestology could potentially use modern analogues from intense storms in this region to extend the hurricane record back to pre-observational time. Existing empirically based models can back-calculate surge heights over coastal systems as a function of transport distance, particle settling velocity, and gravitational acceleration. We collected cores in a …

An Integrated Drought Index (Idi) Incorporating Physical And Social Aspects, Rebecca L. Lanier

Master's Theses

The purpose of this research was to determine significant bio-physical (physical and environmental) and social variables that can be integrated into a drought index to predict areas susceptible to drought. Severe drought events are capable of causing millions of dollars in damage. The 1988 drought caused the United States approximately $40 billion in damage. Drought forecasting, modeling, and detection have, therefore, become imperative to understand the social, economic and environmental impacts of droughts, and also to explore how these impacts play a role in the occurrence of a drought. A number of drought indices widely used in the U.S. rely …

Coastal Hurricane Damage Assessment Via Wavelet Transform Of Remotely Sensed Imagery, Ricky Carl Crowsey

Dissertations

This dissertation uses post storm imagery processed using wavelet transforms to investigate the capability of wavelet transform-based methods to classify post storm damage of residential areas. Five level Haar, Meyer, Symlets, and Coiflets wavelet transform decompositions of the post storm imagery are inputs to damage classification models of post hurricane and tornado damage. Hurricanes Ike, Rita, Katrina, and Ivan are examined as are the 2011 Joplin and Tuscaloosa tornadoes.

Wavelet transform-based classification methods yielded varying classification accuracies for the four hurricanes examined, ranging from 67 percent to 89 percent classification accuracy for classification models informed by samples from the storms …

Precipitation Rates And Atmospheric Heat Transport During The Cenomanian Greenhouse Warming In North America: Estimates From A Stable Isotope Mass-Balance Model, David F. Ufnar, Greg A. Ludvigson, Luis González, Darren R. Gröcke

Faculty Publications

Stable isotope mass-balance modeling results of meteoric δ¹⁸O values from the Cenomanian Stage of the Cretaceous Western Interior Basin (KWIB) suggest that precipitation and evaporation fluxes were greater than that of the present and significantly different from simulations of Albian KWIB paleohydrology. Sphaerosiderite meteoric δ¹⁸O values have been compiled from the Lower Tuscaloosa Formation of southwestern Mississippi (25°N paleolatitude), The Dakota Formation Rose Creek Pit, Fairbury Nebraska (35°N) and the Dunvegan Formation of eastern British Columbia (55°N paleolatitude). These paleosol siderite δ¹⁸O values define a paleolatitudinal gradient ranging from − 4.2‰ VPDB at 25°N …

Monsoon-Driven Biogeochemical Processes In The Arabian Sea, Jerry D. Wiggert, Raleigh Hood, Karl Banse, John Kindle

Faculty Publications

Although it is nominally a tropical locale, the semiannual wind reversals associated with the Monsoon system of the Arabian Sea result annually in two distinct periods of elevated biological activity. While in both cases monsoonal forcing drives surface layer nutrient enrichment that supports increased rates of primary productivity, fundamentally different entrainment mechanisms are operating in summer (Southwest) and winter (Northeast) Monsoons. Moreover, the intervening intermonsoon periods, during which the region relaxes toward oligotrophic conditions more typical of tropical environments, provide a stark contrast to the dynamic biogeochemical activity of the monsoons. The resulting spatial and temporal variability is great and …