ICESat-2: A View Forward (Invited)

NASA’s Ice Cloud and land Elevation Satellite (ICESat), has literally and figuratively added a new dimension to polar and terrestrial research, revealing very dynamic behavior of the Earth’s polar ice sheets and a substantial thinning Arctic sea ice cover. In addition, ICESat has made numerous contributions in other areas of science, including a large-scale assessment of vegetation height as a proxy for biomass. ICESat-2, currently planned for launch in 2015, will build upon the ICESat’s ground-breaking legacy by making measurements to quantify the amount of change in ice sheets and sea ice and provide key insights into their behavior. It will achieve these objectives through the use of multi-beam measurements based on low-energy high repetition-rate micropulse lidar technology. This implementation will provide significantly more dense coverage than was provided by ICESat with its single-beam profiling laser. On ice sheets it will simultaneously measure surface elevations and slopes, and their changes with time. These observations will enable assessments of annual and seasonal elevation changes in outlet glaciers, drainage basins, and the ice sheet as a whole, which is critical for determining current ice sheet contributions to sea level rise, and how they will change in the future. On sea ice, ICESat-2 will enable estimates of sea ice thickness from freeboard height, and the high repetition rate will enable flexibility in lead widths observed, which is a key factor in observing sea ice freeboard. For vegetation, ICESat-2 is expected to contribute to vegetation and ecosystem science objectives to complement measurements made by the Deformation Ecosystem Structure and Dynamics of Ice (DESDynI) mission. With a 2015 scheduled launch date, and a five-year mission life, ICESat-2 will produce measurements of ice changes that span a period of more than 15 years, providing key insights to the behavior of one of the most rapidly changing components of the climate system.