Abstracts Category : Other

Climate dynamics revealed in ice cores: advances in techniques, theory, and interpretation

by Bradley R Markle

Ice cores from the polar ice sheets provide detailed histories of Earth's climate. Interpreting past climate dynamics from ice-core records requires understanding how the climate system influences the geochemical proxies preserved in the ice. Models of physical climate processes have always formed the basis of climate-proxy interpretations. In this thesis I investigate how atmospheric transport of moisture toward the poles influences the water-isotope ratios of Antarctic precipitation as well as the amount of aerosols that reach the ice sheets. I refine interpretations of these geochemical proxies and the relationships between them. These interpretations help us better understand past climate dynamics, including changes in mid- and high-latitude temperatures and changes in the patterns of atmospheric circulation in the Southern Hemisphere. I make use of new high-resolution proxy records from a West Antarctic ice core and use both simple and complex physical models to better understand the relationships between the climate, moisture transport, and the geochemical proxies. This work improves our understanding of the spatial pattern and timing of climate changes in the Southern Hemisphere over the last 70,000 years.Advisors/Committee Members: Steig, Eric J (advisor).