Next Generation Estimates of Antarctic Ice Shelf Melt Rates

Fernando Paolo1, Johan Nilsson1 and Alex S Gardner2, (1)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (2)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, United States
Abstract:
A key limitation in our ability to predict future sea level lies in our insufficient understanding of the processes at the interface between the ice sheet and the ocean. At this boundary, the warming oceans exchange mass and heat with the floating ice shelves, inducing rapid melting of key Antarctic regions with large sea-level potential. Ice-shelf basal melt rates are highly localized in space (e.g. near the grounding lines, along basal melt channels, at the ice-shelf front) and are variable in time (e.g. seasonal influxes of warm ocean waters into the sub-ice-shelf cavities, ENSO-induced melting). Melting of ice shelves not only affects the flow of grounded ice to the ocean through changes in ice-shelf buttressing, but also directly affects the state of the ocean and sea-ice formation around Antarctica. Here, we present the next-generation Antarctic ice-shelf melt-rate product. A synthesis of 25+ years of satellite observations to estimate the changes in ice-shelf meltwater production since 1992 to present. We incorporate ice-shelf freeboard measurements from five ESA and NASA satellite altimetry missions, as well as ice velocities derived from Landsat optical imagery. We will compare some ice shelves with different melt regimes, contrasting ice shelves in near steady state vs. out of balance. We will show the spatial melt patterns of previously unresolved key ice shelves in East Antarctica (e.g. Totten, Shackleton). Finally, we will put these new findings in the context of our current knowledge of the changes taking place around Antarctica.