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The Northwestern Greenland Ice Sheet During The Early Pleistocene Was Similar To Today, Andrew J. Christ, Paul R. Bierman, Paul C. Knutz, Lee B. Corbett, Julie C. Fosdick, Elizabeth K. Thomas, Owen C. Cowling, Alan J. Hidy, Marc W. Caffee

College of Arts and Sciences Faculty Publications

The multi-million year history of the Greenland Ice Sheet remains poorly known. Ice-proximal glacial marine diamict provides a direct but discontinuous record of ice sheet behavior; it is underutilized as a climate archive. Here, we present a novel multiproxy analysis of an Early Pleistocene marine diamict from northwestern Greenland. Low cosmogenic nuclide concentrations indicate minimal near-surface exposure, similar to modern terrestrial sediment. Detrital apatite (U-Th-Sm)/He (AHe) ages all predate glaciation by >150 million years, suggesting the northwestern Greenland Ice Sheet had, by 1.9 Ma, not yet incised fjords of sufficient depth to excavate grains with young AHe ages. The diamict …

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 …

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 …

Past, Present, And Future Arctic Climate And National/Community Risk Assessment, Jeff Auger

Electronic Theses and Dissertations

The Arctic is warming at a rate nearly double that of the global average. The enhanced rate of warming impacts weather and climate across the Northern Hemisphere. As the meridional (south to north) thermal gradient weakens, the middle-latitude westerlies are expected to slow and become “wavier” increasing heat and moisture advection to higher latitudes. A quasi-stationary ridge-trough system of the jet stream increases chances for droughts, floods, heatwaves, and cold spells. These impacts have already been observed as North American forest fires and early or extended Great Lake ice out. It is more important than ever to understand how the …

Wildfires In The Northeastern United States: Evaluating Fire Occurrence And Risk In The Past, Present, And Future, Daniel R. Miller

Doctoral Dissertations

Climate change is one of the most complex and challenging issues facing the world today. A changing climate will affect humankind in many ways and alter our physical environment, presenting ethical challenges in how we respond. The impact of climate change will likely be exacerbated in heavily populated regions of the planet, such as the Northeastern United States (NEUS). The NEUS is comprised of complex, sprawling urban centers and rural regions, both of which are vital to the economic and cultural character of the region. Furthermore, both urban and rural areas in the NEUS contain communities that have been historically …

A Diatom Proxy For Seasonality Over The Last Three Millennia At June Lake, Eastern Sierra Nevada (Ca), Laura Caitlin Streib

Theses and Dissertations--Earth and Environmental Sciences

The Sierra Nevada snowpack is vital to the water supply of California, the world’s sixth largest economy. Though tree ring and instrumental records show the dramatic influence of environmental change on California’s hydroclimate over the last millennium, few proxy archives assess winter precipitation variability farther back in time. Here, we use diatoms from a ~3,200 yr. old sediment core to reconstruct the paleolimnology of June Lake, a hydrologically closed glacial lake in the eastern Sierra Nevada. We test the hypothesis that limnologic and climatic changes control diatom assemblages at June Lake. Fossil diatom assemblages from June Lake sediments chiefly consist …