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Data Set ID:

GLAS/ICESat L1A Global Engineering 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-1A global engineering data (GLA03) include satellite housekeeping data used to calibrate data values for GLA01 and GLA02. 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.

Geographic Coverage

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:
  • 20 February 2003 to 11 October 2009
Temporal Resolution: 3 hour
  • Sensor Characteristics > Total Temperature
Platform(s) ICESAT
Data Format(s):
  • Binary
Version: V33
Data Contributor(s): H. Zwally, Robert Schutz, James Abshire

Data Citation

As a condition of using these 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, and J. Abshire. 2011. GLAS/ICESat L1A Global Engineering Data, Version 33. [Indicate subset used]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: [Date Accessed].
No technical references available for this data set.


Why is spatial searching not enabled for GLA01 (GLAH01) to GLA04 (GLAH04)?

The orbit for GLA01 (GLAH01) and GLA02 (GLAH02) is a predicted orbit and does not show any target-of-opportunity pointing. The GLAS science team decided not to enable spatial searching for these two products in... read more

How To

How to convert GLAS Binary elevation data to WGS-84

The data tool NGAT provides the option of including a new variable (i_deltaEllip) whose
value is Surface Elevation (T/P ellipsoid) minus Surface Elevation (WGS84 ellipsoid).

This product variable will be added to the end of your output record if you set
"... read more