Cryosat-2

CryoSat-2 is ESA’s polar ice-monitoring satellite, launched 8 April 2010 after the original CryoSat was lost in a 2005 launch failure. It carries SIRAL, a Ku-band synthetic-aperture interferometric radar altimeter operating in low-resolution, SAR, and SARIn modes, with a dual antenna for single-pass interferometry over sloping ice-sheet margins. CryoSat-2 measures sea-ice freeboard at about 250 m along-track resolution and resolves Arctic sea-ice thinning to roughly 1.6 cm per year. Radar freeboard is converted to ice thickness with a snow-load and density assumption. Its radar return, which penetrates dry snow, complements the laser freeboard from ICESat-2 and anchors ice-sheet elevation-change records.