Ice Shelf Area and Ice Shelf Area Change from Sentinel-1 SAR and Cryosat-2 Altimetry Data

Kurzfassung

Floating ice shelves fringe 74% of Antarctica's coastline, providing a direct link between the ice sheet and the surrounding oceans. A better understanding of Antarctic ice shelves and the physical processes affecting them has been the main objective of ESA’s Polar+ Ice Shelves project. A suite of geophysical products based on Earth Observation datasets from the last decade and modelling has been defined and produced over selected target ice shelves in Antarctica. One of these products, the ice shelf area change, is an important indicator of ice shelf stability in a warming climate, being affected by grounding line retreat as a possible consequence of ice thinning and calving events including ice shelf disintegration or collapse. An ice shelf is bounded at its seaward margin by the calving front while its inland border to the grounded ice of the Antarctic continent is given by the grounding line. Our calving front location is derived from Cryosat-2 swath elevation, while the grounding line is detected as the upper limit of ice shelf tidal flexure from Sentinel-1 and, prior to 2015, ERS-1/2 interferometric data. Time series of complete ice shelf delineations are obtained from the combination of these two products. It is possible to track absolute and relative area change of an ice shelf and additionally to partition the change into the individual contributions induced by the calving front and grounding-line migration. Examples of annual ice shelf perimeters of major ice shelves from 2011 to the present will be shown.