Entry_ID: NSIDC-0092
Entry_Title: Greenland 5 km DEM, Ice Thickness, and Bedrock Elevation Grids
Group: Data_Set_Citation
   Dataset_Creator: J. Bamber
   Dataset_Title: Greenland 5 km DEM, Ice Thickness, and Bedrock Elevation Grids
   Dataset_Release_Date: 2001-01-01
   Dataset_Release_Place: Boulder, Colorado USA
   Dataset_Publisher: NSIDC: National Snow and Ice Data Center
   Online_Resource: http://nsidc.org/data/nsidc-0092.html
End_Group
Group: Personnel
   Role: Investigator
   First_Name: Jonathan
   Last_Name: Bamber
   Email: j.l.bamber@bristol.ac.uk
   Group: Contact_Address
      Address: Bristol Glaciology Centre
      Address: School of Geographical Sciences
      Address: University Road
      Address: Bristol, BS8 1SS
      Address: UNITED KINGDOM
   End_Group
End_Group
Group: Personnel
   Role: Technical Contact
   First_Name: NSIDC
   Last_Name: User Services
   Email: nsidc@nsidc.org
   Phone: 1 303 492-6199 x
   Fax: 1 303  492-2468 x
   Group: Contact_Address
      Address: National Snow and Ice Data Center
      Address: CIRES, 449 UCB
      Address: University of Colorado
      City: Boulder
      Province_or_State: CO
      Postal_Code: 80309-0449
      Country: USA
   End_Group
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Cryosphere
   Term: Glaciers/Ice Sheets
   Variable_Level_1: Glacier Elevation/Ice Sheet Elevation
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Cryosphere
   Term: Glaciers/Ice Sheets
   Variable_Level_1: Glacier Thickness/Ice Sheet Thickness
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Cryosphere
   Term: Glaciers/Ice Sheets
   Variable_Level_1: Glacier Topography/Ice Sheet Topography
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Cryosphere
   Term: Glaciers/Ice Sheets
   Variable_Level_1: Ice Sheets
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Cryosphere
   Term: Snow/Ice
   Variable_Level_1: Ice Depth/Thickness
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Land Surface
   Term: Topography
   Variable_Level_1: Landforms
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Land Surface
   Term: Topography
   Variable_Level_1: Topographical Relief
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Land Surface
   Term: Topography
   Variable_Level_1: Topographic Effects
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Terrestrial Hydrosphere
   Term: Glaciers/Ice Sheets
   Variable_Level_1: Glacier Elevation/Ice Sheet Elevation
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Terrestrial Hydrosphere
   Term: Glaciers/Ice Sheets
   Variable_Level_1: Glacier Thickness/Ice Sheet Thickness
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Terrestrial Hydrosphere
   Term: Glaciers/Ice Sheets
   Variable_Level_1: Glacier Topography/Ice Sheet Topography
End_Group
Group: Parameters
   Category: EARTH SCIENCE
   Topic: Terrestrial Hydrosphere
   Term: Glaciers/Ice Sheets
   Variable_Level_1: Ice Sheets
End_Group
Keyword: Altimetry
Keyword: Bedrock Elevation
Keyword: DAAC
Keyword: Dem
Keyword: Digital Elevation Model
Keyword: Echo Sounder
Keyword: EOSDIS
Keyword: Greenland
Keyword: Ice Penetrating Radar
Keyword: Ice Sheet
Keyword: Ice Sheet Elevation
Keyword: Ice Thickness
Keyword: IPR
Keyword: NASA
Keyword: PARCA
Keyword: Radar
Keyword: Surface Elevation
Keyword: Topography
Sensor_Name: ALTIMETERS
Sensor_Name: ATM > Airborne Topographic Mapper
Sensor_Name: ECHO SOUNDERS
Sensor_Name: RA > ERS Radar Altimeter
Sensor_Name: RADAR ALTIMETERS
Sensor_Name: RADAR ECHO SOUNDERS
Source_Name: AIRCRAFT
Source_Name: DEM > Digital Elevation Model
Source_Name: ERS-1 > European Remote Sensing Satellite-1
Source_Name: GEOSAT > Geodetic Satellite
Source_Name: MAPS
Source_Name: SATELLITES
Group: Temporal_Coverage
   Start_Date: 1970-01-01
   Stop_Date: 1970-12-01
End_Group
Group: Temporal_Coverage
   Start_Date: 1993-01-01
   Stop_Date: 1999-12-31
End_Group
Data_Set_Progress: complete
Group: Spatial_Coverage
   Southernmost_Latitude: 60
   Northernmost_Latitude: 84
   Westernmost_Longitude: -72
   Easternmost_Longitude: -15
End_Group
Group: Location
   Location_Category: CONTINENT
   Location_Type: NORTH AMERICA
   Location_Subregion1: GREENLAND
End_Group
Project: PARCA > Program in Arctic Regional Climate Assessment
Group: Quality

   Various methods were applied to improve the accuracy of elevation estimates 
   over the Greenland ice sheet, including waveform tracking, slope correction, 
   data filtering (tests for return-echo waveform shape, backscatter coefficient, 
   and retracking correction values for each altimeter height estimate), and 
   removal of anomalous orbits.

   Errors in the estimate of derived ice thickness measurements were determined 
   by comparing the radar-based measurements with those from the Greenland Ice 
   Sheet Project (GISP) and Greenland Ice Core Project (GRIP) ice cores.  Results 
   showed that radar-based measurements were within 10 m of ice core 
   measurements.  No corrections were made for firn effect.

   Since elevation and ice thickness data from the 1970s were much less accurate 
   than the 1990s data, errors in the merged grid were most significant where 
   1970s and 1990s tracks were in close proximity.  Errors in the 1970s data did 
   not cause anomalously high ice thickness gradients at a distance of three grid 
   points (15 km) away from the 1990s data, so gridded data points closer than 
   three grid cells to the 1990s data were removed (Bamber, Layberry, and 
   Gogenini 2000). See guide document for a more complete description.

End_Group
Data_Set_Language: English
Group: Data_Center
   Data_Center_Name: NASA DAAC > NASA DAAC at the National Snow and Ice Data Center
   Data_Center_URL: http://nsidc.org/daac/index.html
   Group: Personnel
      Role: Data Center Contact
      First_Name: NSIDC
      Last_Name: User Services
      Email: nsidc@nsidc.org
      Phone: 1 303 492-6199 
      Fax: 1 303  492-2468 
      Group: Contact_Address
         Address: National Snow and Ice Data Center
         Address: CIRES, 449 UCB
         Address: University of Colorado
         City: Boulder
         Province_or_State: CO
         Postal_Code: 80309-0449
         Country: USA
      End_Group
   End_Group
End_Group
Group: Data_Center
   Data_Center_Name: NSIDC > National Snow and Ice Data Center
   Data_Center_URL: http://nsidc.org
   Group: Personnel
      Role: Data Center Contact
      First_Name: NSIDC
      Last_Name: User Services
      Email: nsidc@nsidc.org
      Phone: 1 303 492-6199 
      Fax: 1 303  492-2468 
      Group: Contact_Address
         Address: National Snow and Ice Data Center
         Address: CIRES, 449 UCB
         Address: University of Colorado
         City: Boulder
         Province_or_State: CO
         Postal_Code: 80309-0449
         Country: USA
      End_Group
   End_Group
End_Group
Group: Distribution
   Distribution_Media: FTP
   Distribution_Size: 4.5 MB
   Distribution_Format: ASCII Text (.txt)
End_Group
Group: Reference

   Bamber, J.L., S. Ekholm, W.B. Krabill. 2000.  A new, high-resolution digital 
   elevation model of Greenland fully validated with airborne laser altimeter 
   data. Journal of Geophysical Research.  In press.

   Bamber, J.L., R.L. Layberry, S.P. Gogenini. 2000.  A new ice thickness and 
   bedrock dataset for the Greenland ice sheet: part I.  Journal of Geophysical 
   Research.  In press.

   Bamber, J.L., Ekholm, S., and Krabill, W. B. 1998. The accuracy of satellite 
   radar altimeter data over the Greenland ice sheet determined from airborne 
   laser data, Geophysical Research Letters. 25(16): 3177-3180.

   Bamber, J.L. and R.A. Bindschadler. 1997. An improved elevation dataset for 
   climate and ice-sheet modelling: validation with satellite imagery. Annals of 
   Glaciology 25:438-444.   

   Bamber, J.L. and P. Huybrechts. 1996. Geometric boundary conditions for 
   modelling the velocity field of the Antarctic ice sheet.  Annals of Glaciology 
   23:364-373.

   Bamber, J. and C. Bentley. 1994. A comparison of satellite-altimetry and ice 
   thickness measurements of the Ross Ice Shelf, Antarctica.  Annals of 
   Glaciology 20:357-364.

   Bamber, J. 1994. A digital elevation model of the Antarctic ice sheet derived 
   from ERS-1 altimeter data and comparison with terrestrial measurements. Annals 
   of Glaciology 20:48-54.

    Bamber, J. 1994. Ice sheet altimeter processing scheme. International Journal 
   of Remote Sensing 15:925-938.

   Bogorodskiy, V.V., C.R. Bentley, P.E. Gudmandsen. 1985. Radioglaciology.  
   Dordrecht: D. Reidel Publishing Company.

   Brenner, A.C., R.A. Bindschadler, R.H. Thomas, H.J. Zwally. 1983.  
   Slope-induced errors in radar altimetry over continental ice sheets. Journal 
   of Geophysical Research 88:1617-1623.

   Davis C.H., H.J. Zwally. 1993. Geographic and seasonal variations in the 
   surface properties of the ice sheets by satellite radar altimetry. Journal of 
   Glaciology 39:687-697.

   Gogineni, S., D. Tammana, D. Braaten, C. Leuschen, T. Atkins, J. Legarsky, P. 
   Kanagaratnam, J. Stiles, C. Allen, and K. Jezek. 2000.  Coherent radar ice 
   thickness measurements over the Greenland Ice Sheet.  Journal of Geophysical 
   Research. In press.

   Hodge, S.M., D.L. Wright, J.A. Bradley, R. W. Jacobel, N. Skou, and B. Vaughn. 
   1990. Determination of the surface and bed topography in central Greenland.  
   Journal of Glaciology 36(122):17-30.

   Weng, W.L. 1995.  Untitled.  Arctic 48(2):206.

   Zwally, H.J., R.A. Bindschadler, A.C. Brenner, T.V. Martin, R.H. Thomas. 1983. 
   Surface elevation contours of Greenland and Antarctic ice sheets.  Journal of 
   Geophysical Research 88(C3):1589-1596.

End_Group
Group: Summary

   A Digital Elevation Model (DEM), ice thickness grid, and bedrock elevation 
   grid of Greenland acquired as part of the PARCA program are available in ASCII 
   text format at a 5 km grid spacing in a polar stereographic projection. DEM 
   data are a combination of ERS-1 and Geosat satellite radar altimetry data, 
   Airborne Topographic Mapper (ATM) data, and photogrammetric digital height 
   data. Ice thickness data are based on approximately 700,000 data points 
   collected in the 1990s from a University of Kansas airborne ice penetrating 
   radar (IPR). Nearly 30,000 data points were collected in the 1970s from a 
   Technical University of Denmark (TUD) airborne echo sounder. Bamber subtracted 
   the ice thickness grid from the DEM to produce a grid of bedrock elevation 
   values. Applications include studies of gravitational driving stress and ice 
   volume (mass balance) of the Greenland Ice Sheet. Each of the three grids is 
   approximately 1.5 MB. Data are available via FTP. Data access is unrestricted, 
   but we recommend that users register with us. Registered users automatically 
   receive e-mail notification of product updates and changes to processing.

End_Group
Group: Related_URL
   Group: URL_Content_Type
      Type: VIEW RELATED INFORMATION
   End_Group
   URL: http://nsidc.org/data/atlas/
   Description: Atlas of the Cryosphere
End_Group
Group: Related_URL
   Group: URL_Content_Type
      Type: VIEW RELATED INFORMATION
   End_Group
   URL: http://nsidc.org/data/gis/index.html
   Description: GIS Data and Resources at NSIDC
End_Group
Group: Related_URL
   Group: URL_Content_Type
      Type: VIEW RELATED INFORMATION
   End_Group
   URL: http://nsidc.org/data/dems/index.html
   Description: Polar Ice Sheet DEMs and Elevation Data
End_Group
Group: Related_URL
   Group: URL_Content_Type
      Type: VIEW RELATED INFORMATION
   End_Group
   URL: http://nsidc.org/data/dems/index.html
   Description: Polar Ice Sheet DEMs and Topographic Data at NSIDC
End_Group
IDN_Node: USA/NASA
Metadata_Name: CEOS IDN DIF
Metadata_Version: 9.7
DIF_Creation_Date: 2001-01-01
Last_DIF_Revision_Date: 2013-10-03
DIF_Revision_History: Removed all service links and replaced them with one link to a landing page.