Antarctic grounding zone characteristics from CryoSat-2

• Main Authors: Dawson, Geoffrey J., Bamber, Jonathan L.
• Format: Text
• Language: English
• Published: 2019
• Subjects: Amery; Amery Ice Shelf; Amundsen Sea; Antarctic; Antarctic Peninsula; Carlson Inlet; Dronning Maud Land; Evans Ice Stream; Ronne Ice Shelf; Ross Ice Shelf; The Antarctic; The Sentinel; Antarc*; Antarctica; Filchner Ronne Ice Shelf; Filchner-Ronne Ice Shelf; Ice Shelf; Ice Shelves
• Online Access: https://doi.org/10.5194/tc-2019-196; https://www.the-cryosphere-discuss.net/tc-2019-196/

We present the results of mapping the limit of tidal flexure (point F) and hydrostatic equilibrium (point H) of the grounding zone of Antarctic ice shelves from CryoSat-2 standard and swath elevation data. Overall we were able to map 41 % of the grounding zone of the larger floating ice shelves and outlet glaciers in Antarctica. We obtain near-complete coverage of the Filchner-Ronne Ice Shelf and partial coverage of the Ross Ice Shelf, Dronning Maud land and the Antarctic Peninsula, while we could not map a continuous grounding zone for the Amery Ice Shelf and the Amundsen Sea Sector. Tidal amplitude and distance south (i.e. across track spacing) are controlling factors in the quality of the coverage and performance of the approach. The location of the point F agrees well with previous observations that used differential satellite radar interferometry (DInSAR) and ICESat-1, with an average landward bias of 0.1 km and 0.6 km and standard deviation of 1.1 km and 1.5 km for DInSAR and ICESat measurements, respectively. We also compared the results directly with DInSAR interferograms from the Sentinel-1 satellites, acquired over the Evans Ice Stream and the Carlson Inlet (Ronne Ice Shelf) and found good agreement with the mapped points F and H. We present the results of the spatial distribution of the grounding zone width (the distance between points F and H), and used a simple elastic beam model to investigate the relationship between ice thickness and grounding zone width.