UC Irvine

The Greenland and Antarctic ice sheets are losing mass that contributes to sea level rise. Föhn and katabatic winds (downslope winds) can enhance surface melt that can run off into the ocean directly affecting sea level rise and can destabilize ice shelves that provide a buttress force to grounded ice. Despite extensive research, melt associated with föhn or katabatic winds is still not fully understood, nor is the response of these winds and associated melt to climate change.My dissertation examined the role of föhn and katabatic winds on surface melt on the Greenland and Antarctic ice sheets. In my first study, I examined how föhn-induced melt affects the spatial melt pattern of the Antarctic Peninsula (AP), especially south of the Larsen C ice shelf and west of the AP, what fraction of the total melt on the AP is caused by föhn winds, how melt varies through time, and how föhn-induced melt has evolved on the AP. To address these questions, I use in situ meteorological observations to train a Machine Learning algorithm to identify the föhn signature in ERA5 global reanalysis and RACMO2 regional climate model simulations. In my second paper, I used the same föhn detection algorithm to identify the role of föhn winds in rapid ice shelf collapse. I found that föhn winds were present at the time of collapse for the Larsen A and B ice shelves which increased surface melt and pushed sea ice away from the calving front and allowed large period ocean swells to initiate collapse. In my third paper, I expand what I learned on the AP and explore the impact and trends of föhn and katabatic winds on the Greenland and Antarctic ice sheets. The collective results of my dissertation help us understand how föhn and katabatic winds impact surface melt and ice shelf stability with the ultimate goal of understanding future sea level rise. I hope these results will help complete the climate and climate change puzzle and help alleviate the burden of future sea level rise to those who do not have the voice , power, or resources to help themselves and their communities.