Thirty years of change on Wilkins and Larsen ice shelves from multi-mission satellite altimetry

We use data from satellite radar (SEASAT, ERS-1 and -2, Envisat) and laser (ICESat) altimeters from 1978 to 2008 to determine multidecadal elevation changes for major Antarctic Peninsula ice shelves. SEASAT data (1978) approximately double the length of the altimetry record, and the longer length of the new height record allows us to determine changes in elevation trends over the 30-year period. However, there are several problems associated with synthesizing multi-mission altimeter data that must be addressed before the data can be used to quantify longer-term trends. We review some of these error sources, including orbit error, firn compaction, and surface penetration. We use data from the open ocean to estimate the inter- satellite biases and apply this to the ice shelf data. We also describe new DEMs for Wilkins and Larsen-B developed from SEASAT radar altimetry for the 1978 epoch. The Larsen-B DEM is combined with the new EIGEN-04C geoid and a firn model to generate ice thickness maps for Larsen-B 24 years before this shelf disintegrated in 2002.