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<DIF xmlns="http://gcmd.gsfc.nasa.gov/Aboutus/xml/dif/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://gcmd.gsfc.nasa.gov/Aboutus/xml/dif/ http://gcmd.gsfc.nasa.gov/Aboutus/xml/dif/dif_v9.7.1.xsd">
  <Entry_ID>NSIDC-0305</Entry_ID>
  <Entry_Title>GLAS/ICESat 1 km Laser Altimetry Digital Elevation Model of Greenland</Entry_Title>
  <Data_Set_Citation>
    <Dataset_Creator>John P. DiMarzio</Dataset_Creator>
    <Dataset_Title>GLAS/ICESat 1 km Laser Altimetry Digital Elevation Model of Greenland</Dataset_Title>
    <Dataset_Release_Date>2007-06-21</Dataset_Release_Date>
    <Dataset_Release_Place>Boulder, Colorado USA</Dataset_Release_Place>
    <Dataset_Publisher>NSIDC: National Snow and Ice Data Center</Dataset_Publisher>
    <Online_Resource>http://nsidc.org/data/nsidc-0305.html</Online_Resource>
  </Data_Set_Citation>
  <Personnel>
    <Role>Investigator</Role>
    <First_Name>John</First_Name>
    <Last_Name>Dimarzio</Last_Name>
    <Email>john.dimarzio@gsfc.nasa.gov</Email>
    <Phone>1 301 614-5893 </Phone>
    <Contact_Address>
      <Address>NASA/Goddard Space Flight Center</Address>
      <Address>SGT, Inc.</Address>
      <Address>SGT, Inc.</Address>
      <Address>NASA/Goddard Space Flight Center</Address>
      <Address>Cryospheric Sciences Branch Code 614.1</Address>
      <City>Greenbelt</City>
      <Province_or_State>MD</Province_or_State>
      <Postal_Code>20771</Postal_Code>
      <Country>USA</Country>
    </Contact_Address>
  </Personnel>
  <Personnel>
    <Role>Investigator</Role>
    <First_Name>Anita</First_Name>
    <Last_Name>Brenner</Last_Name>
    <Email>anita.brenner@gsfc.nasa.gov</Email>
    <Contact_Address>
      <Address>NASA/Goddard Space Flight Center</Address>
      <Address>SSAI</Address>
      <Address>Code 614.5</Address>
      <City>Greenbelt</City>
      <Province_or_State>MD</Province_or_State>
      <Postal_Code>20771</Postal_Code>
      <Country>USA</Country>
    </Contact_Address>
  </Personnel>
  <Personnel>
    <Role>Investigator</Role>
    <First_Name>Helen</First_Name>
    <Last_Name>Fricker</Last_Name>
    <Contact_Address>
      <Address>Scripps Institution of Oceanography</Address>
      <Address>Institute of Geophysics and Planetary Physics</Address>
      <Address>University of California, San Diego</Address>
      <Address>9500 Gilman Dr.</Address>
      <City>La Jolla</City>
      <Province_or_State>California</Province_or_State>
      <Postal_Code>92093</Postal_Code>
      <Country>USA</Country>
    </Contact_Address>
  </Personnel>
  <Personnel>
    <Role>Investigator</Role>
    <First_Name>Robert</First_Name>
    <Last_Name>Schutz</Last_Name>
    <Contact_Address>
      <Address>University of Texas at Austin</Address>
      <Address>Center for Space Research</Address>
      <Address>GLAS Science Team Lead</Address>
      <Address>University of Texas at Austin</Address>
      <Address>Center for Space Research</Address>
      <City>Austin</City>
      <Province_or_State>TX</Province_or_State>
      <Postal_Code>78712-1085</Postal_Code>
      <Country>USA</Country>
    </Contact_Address>
  </Personnel>
  <Personnel>
    <Role>Investigator</Role>
    <First_Name>Christopher</First_Name>
    <Middle_Name>A.</Middle_Name>
    <Last_Name>Shuman</Last_Name>
    <Email>Christopher.A.Shuman@nasa.gov</Email>
    <Phone>1 301 614-5706 </Phone>
    <Contact_Address>
      <Address>NASA/Goddard Space Flight Center</Address>
      <Address>Cryospheric Sciences Branch</Address>
      <Address>Cryospheric Sciences Branch</Address>
      <Address>Code 614.1</Address>
      <Address>NASA/Goddard Space Flight Center</Address>
      <City>Greenbelt</City>
      <Province_or_State>MD</Province_or_State>
      <Postal_Code>20771</Postal_Code>
      <Country>USA</Country>
    </Contact_Address>
  </Personnel>
  <Personnel>
    <Role>Investigator</Role>
    <First_Name>H. Jay</First_Name>
    <Last_Name>Zwally</Last_Name>
    <Email>Jay.Zwally@nasa.gov</Email>
    <Phone>1 301 614-5643 </Phone>
    <Fax>1 301  614-5644 </Fax>
    <Contact_Address>
      <Address>NASA/Goddard Space Flight Center</Address>
      <Address>Laboratory for Hydrospheric Processes</Address>
      <Address>Laboratory for Hydrospheric Processes</Address>
      <Address>NASA/Goddard Space Flight Center</Address>
      <Address>Code 971</Address>
      <City>Greenbelt</City>
      <Province_or_State>MD</Province_or_State>
      <Postal_Code>20771</Postal_Code>
      <Country>USA</Country>
    </Contact_Address>
  </Personnel>
  <Personnel>
    <Role>Technical Contact</Role>
    <First_Name>NSIDC</First_Name>
    <Last_Name>User Services</Last_Name>
    <Email>nsidc@nsidc.org</Email>
    <Phone>1 303 492-6199 x</Phone>
    <Fax>1 303  492-2468 x</Fax>
    <Contact_Address>
      <Address>National Snow and Ice Data Center</Address>
      <Address>CIRES, 449 UCB</Address>
      <Address>University of Colorado</Address>
      <City>Boulder</City>
      <Province_or_State>CO</Province_or_State>
      <Postal_Code>80309-0449</Postal_Code>
      <Country>USA</Country>
    </Contact_Address>
  </Personnel>
  <Parameters>
    <Category>EARTH SCIENCE</Category>
    <Topic>Cryosphere</Topic>
    <Term>Glaciers/Ice Sheets</Term>
    <Variable_Level_1>Glacier Elevation/Ice Sheet Elevation</Variable_Level_1>
  </Parameters>
  <Parameters>
    <Category>EARTH SCIENCE</Category>
    <Topic>Cryosphere</Topic>
    <Term>Glaciers/Ice Sheets</Term>
    <Variable_Level_1>Glacier Elevation/Ice Sheet Elevation</Variable_Level_1>
  </Parameters>
  <Parameters>
    <Category>EARTH SCIENCE</Category>
    <Topic>Terrestrial Hydrosphere</Topic>
    <Term>Glaciers/Ice Sheets</Term>
    <Variable_Level_1>Glacier Elevation/Ice Sheet Elevation</Variable_Level_1>
  </Parameters>
  <Parameters>
    <Category>EARTH SCIENCE</Category>
    <Topic>Terrestrial Hydrosphere</Topic>
    <Term>Glaciers/Ice Sheets</Term>
    <Variable_Level_1>Glacier Elevation/Ice Sheet Elevation</Variable_Level_1>
  </Parameters>
  <ISO_Topic_Category>Elevation</ISO_Topic_Category>
  <Keyword>Altimetry</Keyword>
  <Keyword>Dem</Keyword>
  <Keyword>Digital Elevation Model</Keyword>
  <Keyword>Elevation</Keyword>
  <Keyword>Greenland</Keyword>
  <Keyword>Ice Sheet</Keyword>
  <Keyword>Ice Sheet Elevation</Keyword>
  <Keyword>Polar</Keyword>
  <Keyword>Polar Stereographic</Keyword>
  <Sensor_Name>
    <Short_Name>GLAS</Short_Name>
    <Long_Name>Geoscience Laser Altimeter System</Long_Name>
  </Sensor_Name>
  <Source_Name>
    <Short_Name>ICESAT</Short_Name>
    <Long_Name>Ice, Cloud and Land Elevation Satellite</Long_Name>
  </Source_Name>
  <Temporal_Coverage>
    <Start_Date>2003-02-01</Start_Date>
    <Stop_Date>2005-06-30</Stop_Date>
  </Temporal_Coverage>
  <Data_Set_Progress>complete</Data_Set_Progress>
  <Spatial_Coverage>
    <Southernmost_Latitude>60</Southernmost_Latitude>
    <Northernmost_Latitude>83</Northernmost_Latitude>
    <Westernmost_Longitude>-73</Westernmost_Longitude>
    <Easternmost_Longitude>-11</Easternmost_Longitude>
  </Spatial_Coverage>
  <Location>
    <Location_Category>CONTINENT</Location_Category>
    <Location_Type>NORTH AMERICA</Location_Type>
    <Location_Subregion1>GREENLAND</Location_Subregion1>
  </Location>
  <Data_Resolution>
    <Latitude_Resolution>1 km</Latitude_Resolution>
    <Longitude_Resolution>1 km</Longitude_Resolution>
  </Data_Resolution>
  <Project>
    <Short_Name>ICESAT</Short_Name>
    <Long_Name>Ice, Cloud and Land Elevation Satellite</Long_Name>
  </Project>
  <Quality>Slope and elevation accuracy of the DEMs is best near the latitudinal limit of satellite coverage (±86°), and provides a good representation of the ice sheet and mountain areas (based on comparison with satellite images). DEM accuracy decreases as track spacing between ICESat profiles increases equatorward.

As a quality and accuracy indicator, the mean distance of all contributing GLAS surface spot data to the grid cell center was recorded in a separate identical grid for each ice sheet. These mean distance files are provided with the elevation data.</Quality>
  <Data_Set_Language>English</Data_Set_Language>
  <Data_Center>
    <Data_Center_Name>
      <Short_Name>NSIDC_DAAC</Short_Name>
      <Long_Name>NASA DAAC at the National Snow and Ice Data Center</Long_Name>
    </Data_Center_Name>
    <Data_Center_URL>http://nsidc.org/daac/index.html</Data_Center_URL>
    <Personnel>
      <Role>Data Center Contact</Role>
      <First_Name>NSIDC</First_Name>
      <Last_Name>User Services</Last_Name>
      <Email>nsidc@nsidc.org</Email>
      <Phone>1 303 492-6199 </Phone>
      <Fax>1 303  492-2468 </Fax>
      <Contact_Address>
        <Address>National Snow and Ice Data Center</Address>
        <Address>CIRES, 449 UCB</Address>
        <Address>University of Colorado</Address>
        <City>Boulder</City>
        <Province_or_State>CO</Province_or_State>
        <Postal_Code>80309-0449</Postal_Code>
        <Country>USA</Country>
      </Contact_Address>
    </Personnel>
  </Data_Center>
  <Data_Center>
    <Data_Center_Name>
      <Short_Name>NSIDC</Short_Name>
      <Long_Name>National Snow and Ice Data Center</Long_Name>
    </Data_Center_Name>
    <Data_Center_URL>http://nsidc.org</Data_Center_URL>
    <Personnel>
      <Role>Data Center Contact</Role>
      <First_Name>NSIDC</First_Name>
      <Last_Name>User Services</Last_Name>
      <Email>nsidc@nsidc.org</Email>
      <Phone>1 303 492-6199 </Phone>
      <Fax>1 303  492-2468 </Fax>
      <Contact_Address>
        <Address>National Snow and Ice Data Center</Address>
        <Address>CIRES, 449 UCB</Address>
        <Address>University of Colorado</Address>
        <City>Boulder</City>
        <Province_or_State>CO</Province_or_State>
        <Postal_Code>80309-0449</Postal_Code>
        <Country>USA</Country>
      </Contact_Address>
    </Personnel>
  </Data_Center>
  <Distribution>
    <Distribution_Media>FTP</Distribution_Media>
    <Distribution_Size>24 MB</Distribution_Size>
    <Distribution_Format>Binary</Distribution_Format>
  </Distribution>
  <Reference>Abshire, J., and 8 others. 2005. Geoscience Laser Altimeter System (GLAS) on the ICESat mission: on-orbit measurement performance. Geophysical Research Letters v. 32, L21S02, doi:10.1029/2005GL1024028. 

Brenner, A., and 11 others. 2003. Derivation of range and range distributions from laser pulse waveform analysis for surface elevations, roughness, slope, and vegetations heights, Algorithm Theoretical Basis Document (ATBD) v.4.1, available at http://www.csr.utexas.edu/glas/atbd.html.

DiMarzio, J. P., A. C. Brenner, and H. J. Zwally. 2004. Comparison of Envisat and ERS radar altimetry for ice sheet elevation change studies. ESA Envisat Sympsium, Salzburg, Austria, September 9, 2004.

Krabill, W., W. Abdalati, and 7 others. 2002. Aircraft laser altimetry measurement of elevation changes of the Greenland Ice Sheet: technique and accuracy assessment. J. Geodynamics 34, 357-376. 

Shuman, C., J. Zwally, B. Schutz, A. Brenner, J. DiMarzio, V. Schuedo, and H. Fricker. 2006. ICESat Antarctic elevation data: preliminary precision and accuracy assessment. Geophysical Research Letters 33, L07501, doi:10.1029/2005GL025227. 

Zwally, H. J., A. C. Brenner, J. A. Major, T. V. Martin, and R. A. Bindschadler. 1990. Satellite radar altimetry over ice, Vol. 1. Processing and corrections of Seasat data over Greenland. NASA Reference Publication 1233.</Reference>
  <Summary>The Geoscience Laser Altimeter System (GLAS) instrument on the Ice, Cloud, and land Elevation Satellite (ICESat) provides global measurements of elevation, and repeats measurements along nearly-identical tracks; its primary mission is to measure changes in ice volume (mass balance) over time. This digital elevation model (DEM) of Greenland is derived from GLAS/ICESat laser altimetry profile data and provides new surface elevation grids of the ice sheets and coastal areas, with greater latitudinal extent and fewer slope-related effects than radar altimetry.

This DEM is generated from the first seven operational periods (from February 2003 through June 2005) of the GLAS instrument. It is provided on polar stereographic grids at 1 km grid spacing. The grid covers all of Greenland south of 83° N. Elevations are reported as centimeters above the datums, relative to both the WGS 84 ellipsoid and the EGM96 geoid, in two separate elevation data files. A data quality map of the interpolation distance is distributed in addition to the elevation data. ENVI header files are also provided.

The data are in 4-byte (long) signed integer binary files (big endian byte order) and are available via FTP.</Summary>
  <Related_URL>
    <URL_Content_Type>
      <Type>VIEW PROJECT HOME PAGE</Type>
    </URL_Content_Type>
    <URL>http://nsidc.org/data/icesat/</URL>
    <Description>ICESat/GLAS Data at NSIDC</Description>
  </Related_URL>
  <Related_URL>
    <URL_Content_Type>
      <Type>VIEW RELATED INFORMATION</Type>
    </URL_Content_Type>
    <URL>http://nsidc.org/data/nsidc-0304.html</URL>
    <Description>GLAS/ICESat 500 m Laser Altimetry Digital Elevation Model of Antarctica</Description>
  </Related_URL>
  <Related_URL>
    <URL_Content_Type>
      <Type>VIEW RELATED INFORMATION</Type>
    </URL_Content_Type>
    <URL>http://nsidc.org/data/dems/</URL>
    <Description>Polar Ice Sheet DEMs and Elevation Data</Description>
  </Related_URL>
  <Metadata_Name>CEOS IDN DIF</Metadata_Name>
  <Metadata_Version>9.7</Metadata_Version>
  <DIF_Creation_Date>2007-06-21</DIF_Creation_Date>
  <Last_DIF_Revision_Date>2012-09-18</Last_DIF_Revision_Date>
  <DIF_Revision_History>deleted broken &amp; dupe URLs in Related URL field</DIF_Revision_History>
</DIF>
