NASA's Ice Cloud and Land Elevation Satellite (ICESat): Providing New Insights into the Changing Cryosphere

Launched on January 12, 2003, NASA's Ice Cloud and land Elevation Satellite (ICESat) provides a new three- dimensional view of the Cryosphere with unprecedented accuracy and precision. This capability has enabled detailed measurements of ice sheet, ice stream, and ice shelf topography, ice elevation changes, and sea ice freeboard in ways that have never been possible before. On the ice sheet margins, where surfaces are rough and slopes are generally steep, ICESat's small footprint enables the detection of major changes that has not been achievable with conventional radar altimeters. ICESat's unprecedented accuracy in measuring surface elevation enables the detection of small elevation changes in the central regions of the vast ice sheets, where changes of a just a few centimeters are of great consequence to the overall ice sheet mass balance. The high precision of the ICESat measurements along with its dense along-track sampling has resulted in the first detailed satellite-derived sea ice thickness estimates, and provides an important new data set for understanding changes in this critical component of the cryosphere. Now into its ninth operations period of 33- day observations in winter, spring, and fall ice cover, the ICESat mission is providing meaningful information for relating changes in the cryosphere to climate conditions that affect those changes. The most recent results of ice sheet characteristics and changes, as well as sea ice thickness observations will be presented, along with a summary of the current state of the ICESat mission and its prospects for continued operation.