Data Sets for Research
Scientific Data Search
Support for Researchers
Data for Everyone
Looking for facts and information? See About the Cryosphere.
Icelights: Answers to your burning questions about ice and climate
What's hot in the news around climate and sea ice and what are scientists talking about now? Read more...
What is the Cryosphere?
When scientists talk about the cryosphere, they mean the places on Earth where water is in its solid form, frozen into ice or snow. Read more ...
The Geoscience Laser Altimeter System (GLAS) instrument on the Ice, Cloud, and Land Elevation Satellite (ICESat) provides global measurements of polar ice sheet elevation to discern changes in ice volume (mass balance) over time. Secondary objectives of GLAS are to measure sea ice roughness and thickness, cloud and atmospheric properties, land topography, vegetation canopy heights, ocean surface topography, and surface reflectivity.
GLAS has a 1064 nm laser channel for surface altimetry and dense cloud heights, and a 532 nm lidar channel for the vertical distribution of clouds and aerosols.
Level-1A global laser pointing data (GLA04) contain two orbits of attitude data from the spacecraft star tracker, instrument star tracker, gyro, and laser reference system, and other spacecraft attitude data required to calculate precise laser pointing. Data are in scaled integer binary format, big-endian (Unix) byte order, and are available via FTP.
For information about Version 33, see the NSIDC ICESat Description of Data Releases page.
N: 86, S: -86, E: 180, W: -180