Buoyancy-Driven Flexure At The Front Of Ross Ice Shelf, Antarctica, Observed With Icesat-2 Laser Altimetry

Mass loss from Antarctica's three largest ice shelves is dominated by calving, primarily of large tabular icebergs every few decades. Smaller, more frequent calving events also occur, but it is more difficult to detect them and quantify their contribution to total ice-shelf mass loss. We used surface elevation data from NASA's ICESat-2 laser altimeter to examine the structure of the Ross Ice Shelf front between October 2018 and July 2020. Profiles frequently show a depression a few meters deep about 200-800 m upstream of the front, with higher values on the eastern portion of the ice shelf. This structure results from bending due to buoyancy of a submerged ice bench generated by ice-front melting near the waterline when warm water is present in summer. These bending stresses may cause small-scale calving events whose frequency would change as summer sea ice and atmosphere-ocean heat exchanges vary over time.