Sea Ice Freeboard and Thickness from Space-borne Altimetry
Laxon, Seymour; Farrell, Sinead; Giles, Katharine; Andrew, Ridout
UCL-CPOM

The radar altimeters on-board ESA's ERS satellites were the first to provide basin-wide estimates of sea ice thickness from direct measurements of sea ice freeboard. We review the current status of sea ice retrievals from the Envisat mission. We discuss issues related to cross-calibration with the ERS missions and highlight key differences in the instrument characteristics. We will also show inter-comparisons also with water and ice elevation estimates from NASA's IceSat mission and discuss the potential of both missions to provide snow depth retrievals and discuss the potential of satellite altimetry in the Southern Ocean. The International Polar Year will in addition provide a unique opportunity to gather field data to reduce and properly quantify the uncertainties in satellite retrievals of ice thickness and mass. Finally we discuss the lessons learnt so far in altimeter retrievals of ice thickness and identify future research goals, in particular looking forward to the exploitation of data from the CryoSat-2 mission.