| Summary: | Increasing mass loss from the Antarctic Ice Sheet has contributed to recent acceleration in the rate of global mean sea-level rise (SLR). Its full SLR potential is ~58 m, and its future contribution remains highly uncertain. The flow of Antarctica’s grounded ice into the ocean, and thus its contribution to SLR, is regulated by buttressing from floating ice shelves. Ice-shelf mass loss can reduce this buttressing effect. In this dissertation, I used satellite and airborne remote sensing data to explore three processes by which the ocean drives mass change on Antarctica’s large Ross Ice Shelf (RIS).First, I compared RIS thicknesses estimated from satellite laser altimetry and ROSETTA-Ice airborne radar data to identify a potential area of basal marine-ice accretion (i.e., local mass gain) in the ice-shelf interior. Large uncertainties prevent a definitive conclusion; reducing uncertainties will require additional measurements of ice-column density and firn properties. Second, I showed that airborne radar thickness profiles capture near-front thinning of RIS associated with basal melting by seasonally warmed upper-ocean water.Finally, I investigated the bending of the RIS front due to buoyancy created by the melting-related development of a submerged bench of ice, a mechanism that may lead to mass loss by calving of small icebergs. Profiles of the ice-shelf surface height from two satellite laser altimetry missions (ICESat, 2003–2009; and ICESat-2, 2018–present) reveal that this bending is larger on the eastern section of the RIS front, reflecting along-front variability in near-front ice thickness and ocean conditions. I also found that the surface deformation increased overall between 2018 and 2022. Between the two satellite mission periods, these surface structures grew along sections of the RIS front that experienced large calving events in the early 2000s.Taken together, these studies demonstrate that important mass-balance processes at the interface of ice shelf and ocean occur at small spatial scales that ...
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