Laser vs. Radar: Shocking Secrets of Earth’s Shrinking Ice Revealed from Space
ICESat-2 (NASA) launched September 15, 2018 on a Delta II rocket and carries the Advanced Topographic Laser Altimeter System (ATLAS), a photon-counting laser that operates from a ~481 km near-polar orbit (92°) with ground tracks repeating every 91 days to map ice sheets, sea-ice freeboard, glacier height, and forest canopy. CryoSat-2 (ESA) launched April 8, 2010 on a Dnepr rocket, in a ~717 km, 92° inclined drifting orbit not sun-synchronous and reaching up to 88° latitude to measure ice thickness on land and sea. ICESat-2 fires about 10,000 laser pulses per second (532 nm green) with six beams, producing an