ICESat-2 has 3 pairs of lasers that will measure the heights of ice and snow at very high resolution
The ATLAS lidar on ICESat-2 uses 6 laser beams to measure the earth’s elevation and elevation change. As a global mission, ICESat-2 will collect data over the entire globe, however the ATLAS instrument is optimized to measure land ice and sea ice elevation in the polar regions. ICESat-2 reports elevations with respect to a reference surface, called an ellipsoid. In this measurement system, shared by GPS devices, an elevation of zero meters indicates the notional sea level, although tides, wind, and waves can make the actual sea level either greater than or less than zero. The Antarctic ice sheet, shown here, ranges up to 4000m above sea level. Over the course of 91 days, ATLAS will generate 1387 ground tracks across Antarctica for each of it’s 6 beams.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 22.214.171.124.0