Data Set ID:

GLAS/ICESat L1B Global Backscatter Data, Version 33

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-1B global backscatter data (GLA07) are provided at full instrument resolution. The product includes full 532 nm (41.1 to -1.0 km) and 1064 nm (20 to -1 km) calibrated attenuated backscatter profiles at 5 times per second, and from 10 to -1 km, at 40 times per second for both channels. Also included are calibration coefficient values and molecular backscatter profiles at once per second. Data granules contain approximately 190 minutes (2 orbits) of data.

Each data granule has an associated browse product that users can quickly peruse to determine the general quality of the data in the granule. Browse products consist of image plots of key parameters and statistics. Data are in scaled integer binary format, big-endian (Unix) byte order, and are available via FTP.

Version Summary:

For information about Version 33, see the NSIDC ICESat Description of Data Releases page.

Get Data

GLAS Subsetter: Order geographic and temporal subsets of the data.
Reverb: NASA search and order tool for subsetting, reprojecting, and reformatting data.

Geographic Coverage

Data Set Tabs

Spatial Coverage:
  • N: 86, S: -86, E: 180, W: -180

Spatial Resolution:
  • 60 m to 70 m x 60 m to 70 m
Temporal Coverage
  • 2003-02-20 to 2009-10-11
Temporal Resolution:
3 hour
  • Aerosols > Aerosol Backscatter > Aerosol Backscatter Cross Section Profile
  • Atmospheric Radiation > Scattering
  • Topography > Terrain Elevation
Data Format(s):
  • Binary
Data Contributor(s): H. Zwally, Robert Schutz, Steve Palm, William Hart, Dennis Hlavka, James Spinhirne, Ellsworth Welton

Data Citation

As a condition of using this data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

Zwally, H. J., R. Schutz, W. Hart, D. Hlavka, and S. Palm. 2011. GLAS/ICESat L1B Global Backscatter Data, Version 33. [indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. [Date Accessed].

Questions? Please contact:

NSIDC User Services
Phone: 1 303 492-6199
Fax: 1 303 492-2468
Contact Address:
National Snow and Ice Data Center
University of Colorado
City: Boulder
Province or State: CO
Postal Code: 80309-0449
Country: USA