Antarctic Grounding Line Mapping From CryoSat‐2 Radar Altimetry

We present a new technique for mapping the grounding line of Antarctic ice shelves using a combination of CryoSat‐2 standard and swath elevation data. Our method is based on detecting the tidal signal in pseudo crossovers and is tested on the Siple Coast region of West Antarctica. The mapped grounding line is in good agreement with previous observations from differential SAR interferometry and from ICESat repeat tracks, with a standard deviation of 1.1 km and 1.0 km, respectively, between these methods and ours. There is, however, an average seaward bias of 0.6 km, which is due to the poorer precision of CryoSat‐2. We have improved coverage particularly near the Echelmeyer Ice Stream where we have shown that the grounding zone is approximately 25 km inland from previous estimates. This new method is computationally efficient and can be applied to the rest of Antarctica. Key Points A new method that allows us to map the limit of ice flexure using CryoSat‐2 data The mapped grounding line is in good agreement with previous DInSAR and ICESat measurements Provides additional coverage of the Antarctic grounding zone