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. This level-2 altimetry product (GLA13) provides surface elevations for sea ice. Data also include the laser footprint gelocation and reflectance, as well as geodetic, instrument, and atmospheric corrections for range measurements. Each data granule has an associated browse product that users can quickly view 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.
Browse products in PNG graphic format contain quality information; these are available along with corresponding data granules in the Data Pool or EOS Data Gateway. The i_FrameQF quality flag is set to '1' if there is a problem in calculating individual parameters, or the flag is set to '0' if there are no problems.
Bae, S. and B.E. Schutz. 2002. Precision attitude determination (PAD). GLAS algorithm theoretical basis document. Version 2.2. Austin, TX: Center for Space Research, University of Texas at Austin.
Brenner, A.C., C.R. Bentley, B.M. Csatho, D.J. Harding, M.A. Hofton, J. Minster, L. Roberts, J.L. Saba, R. Schutz, R.H. Thomas, D. Yi, and H.J. Zwally. 2000. Derivation of range and range ... distributions from laser pulse waveform analysis for surface elevations, roughness, slope, and vegetation heights. Algorithm theoretical basis document. Version 3.0. Greenbelt, MD: Goddard Space Flight Center. Center for Space Research. 'ICESat/GLAS.' January 2002. http://www.csr.utexas.edu/glas/.
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GLAS Science Team. 2000. Mission Operations Requirement Document (MORD) for the Ice, Cloud and Land Elevation Satellite (ICESat) Mission. Greenbelt, MD: Goddard Space Flight Center.
GLAS Science Team. 1997. GLAS Science Requirements. Version 2.01. Greenbelt, MD: Goddard Space Flight Center.
Heroux, D. 2000. Progress report on GLAS interface effort with ECS NOSE. Rev. 29 December 2000. Landover, MD: Emergent-IT/Raytheon.
Herring, T.A. and K. Quinn. 1999. Atmospheric delay correction to GLAS laser altimeter ranges. GLAS algorithm theoretical basis document. Version 1.0. Lanham, MD: Science Systems and Applications, Inc.
Jester, P., and D. Hancock. 2002. The Algorithm Theoretical Basis Document for Level 1A Processing, Version 1.2. Wallops Island, VA: Raytheon ITSS.
Jester, P., and J. Lee. 2002. GLAS standard data products specification - level 1. Version 6.0. Wallops Island, VA: Raytheon ITSS. Lee, J. 2002. GSAS user's guide: Version 4.0. Wallops Island, VA: Raytheon ITSS.
McGarry, J.F., J. Abshire, X. Sun, J. Saba, A. Brenner, and D. Yi. 2002. GLAS flight science data selection algorithms for the altimeter (1064 nm), Version 4.15. Unpublished report.
Rim, H., and B. Schutz. 2002. Precision orbit determination. GLAS algorithm theoretical basis document. Version 2.2. Austin, TX: Center for Space Research, University of Texas at Austin.
Schutz, B. 2000. GLAS altimeter post-launch calibration/validation plan. Version 0.99. Austin, TX: Center for Space Research, University of Texas at Austin.
Schutz, B. 2002. Laser footprint location (geolocation) and surface profiles. GLAS algorithm theoretical basis document. Version 3.0. Austin, TX: Center for Space Research, University of Texas at Austin.
Wahr, J., D. Wingham, and C. Bentley. 2000. A method of combining ICESat and GRACE satellite data to constrain Antarctic mass balance. Journal of Geophysical Research 105(B7):16,279-16,294.
Yi, D., J. Minster, and C. Bentley. 1999. Ocean tidal loading corrections.
GLAS algorithm theoretical basis document. Version 1.0. Greenbelt, MD: Goddard Space Flight Center.
Zwally, H.J., B. Schutz, W. Abdalati, J. Abshire, C. Bentley, A. Brenner, J. Bufton, J. Dezio, D. Hancock, D. Harding, T. Herring, B. Minster, K. Quinn, S. Palm, J. Spinhirne, and R. Thomas. 2002. ICESAT's laser measurements of polar ice, atmosphere, ocean, and land. Journal of Geodynamics 34: 405-445.
Zwally, H.J., B. Schutz, D. Hancock, and A. Brenner. 2000. ICESat/GLAS Standard Data Products in HDF and SCF Formats. Version 1.2. Greenbelt, MD: Goddard Space Flight Center.
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