UC Irvine

This dissertation presents a comprehensive study on the dynamics of ice grounding zones in Antarctica’s ice shelves, with a particular focus on the Amery Ice Shelf and Berry Glacier. Using satellite radar interferometry and other data, this research examines the intricate processes of grounding line migration, ice dynamics, and basal melting. The findings highlight the significant impact of bed topography, subglacial hydrology, and seawater intrusions on ice grounding zone dynamics, challenging traditional models that assume static grounding line positions. In the Amery Ice Shelf region, the study investigates the Lambert, Mellor, and Fisher glaciers, where the analysis of Sentinel-1 data reveals extensive tide-induced grounding line migrations, with movements far exceeding previous estimates. Moreover, high speed of the seawater intrusions brings impressive basal melting in the ice grounding zone. These results underscore the importance of including detailed ice grounding zone processes in ice sheet models to better predict the glaciers’ responses to ocean warming. For Berry Glacier in West Antarctica, the study documents a rapid ice grounding zone retreat over a 25-year period, driven by increased basal melting from warm Circumpolar Deep Water incursions. This retreat has resulted in a marked increase in ice discharge and surface elevation changes, demonstrating the glacier’s accelerated response to oceanic forces. The research presented here contributes to a deeper understanding of the ice grounding zone processes in Antarctica and emphasizes the need for refined modeling approaches that account for the complex interactions between ice, ocean, and subglacial environments. These insights are crucial for improving sea level rise projections and assessing the broader impacts of climate change on polar ice sheets.