Antarctic Ice Shelf Thickness Change from Multi-Mission LidarMapping

Abstract. We calculate rates of ice thickness change and bottom melt for ice shelves in West Antarctica and the Antarctic Peninsula from a combination of elevation measurements from Operation IceBridge corrected for oceanic and surface processes, surface velocity measurements from synthetic aperture radar, and high-resolution outputs from regional climate models. We calculate ice thickness change rates in a Lagrangian reference frame to reduce the effects from advection of sharp vertical features, such as cracks and crevasses, which can saturate Eulerian-derived estimates. We use our method over different ice shelves in Antarctica, which vary in terms of the processes that drive their change, their size and their repeat coverage but are all susceptible to short-term changes in ice thickness. We find that ice thickness variations of the Larsen-C ice shelf are due to the flux divergence of the shelf with firn and surface processes controlling short-term variability over our observation period. The Wilkins ice shelf is sensitive to short time-scale coastal and upper-ocean processes, and basal melt is the dominate contributor to the ice thickness change over the period. At The Pine Island ice shelf in the critical region near in the grounding zone, we find that ice shelf thinning rates exceed 40 m/yr. The thickness change is dominated by strong submarine thinning. Regions near the grounding zones of the Dotson and Crosson ice shelves are thinning at rates greater than 40 m/yr, also due to intense basal melt.