Alaska Geoid Heights (GEOID96)

Description

This 2' x 4' geoid height grid for Alaska is distributed as a GEOID96 model. The computation used 1.1 million terrestrial and marine gravity data held in the National Geodetic Survey gravity data base in July 1996 These data were augmented by gravity data contributions from NGA (former National Imagery and Mapping Agency (former Defence Mapping Agency)). By means of a Fast Fourier Transform (FFT) technique, high frequency corrections were made to an underlying EGM96 geopotential model through a remove, compute, and restore process. The gravity values are based on the International Gravity Standardization Net 1971 (IGSN71). The geoid heights are referred to the Geodetic Reference System 1980 (GRS80) ellipsoid. Unlike the grid for the conterminous United States, this GEOID96 grid does not incorporate GPS on leveled benchmarks. This model is a gravimetric geoid in a geocentric, ITRF94(1996.0) reference frame. It is necessary to subtract 12.0 cm from these values to obtain the geoid undulation between the best-fit global geopotential surface and the GRS80 ellipsoid (both expressed in a tide free system). Additional information is available at: http://www.ngs.noaa.gov/GEOID/geoid.html We are particularly grateful to NGA (former National Imagery and Mapping Agency) for their assistance and their data contributions.

Resources

Name Format Description Link
21 1999cd.html https://www.ngdc.noaa.gov/mgg/gravity/1999cd.html
21 tablegri.html https://www.ngdc.noaa.gov/mgg/gravity/1999/document/html/tablegri.html
0 The information provided on this page seeks to define how the GCMD Keywords are structured, used and accessed. It also provides information on how users can participate in the further development of the keywords. https://earthdata.nasa.gov/about/gcmd/global-change-master-directory-gcmd-keywords
0 The information provided on this page seeks to define how the GCMD Keywords are structured, used and accessed. It also provides information on how users can participate in the further development of the keywords. https://earthdata.nasa.gov/about/gcmd/global-change-master-directory-gcmd-keywords
0 The information provided on this page seeks to define how the GCMD Keywords are structured, used and accessed. It also provides information on how users can participate in the further development of the keywords. https://earthdata.nasa.gov/about/gcmd/global-change-master-directory-gcmd-keywords
21 se-0703.html https://www.ngdc.noaa.gov/mgg/fliers/se-0703.html
0 The information provided on this page seeks to define how the GCMD Keywords are structured, used and accessed. It also provides information on how users can participate in the further development of the keywords. https://earthdata.nasa.gov/about/gcmd/global-change-master-directory-gcmd-keywords

Tags

  • bouguer gravity
  • alaska
  • united states of america
  • land gravity
  • international council for science - world data system
  • nesdis
  • icsu-wds
  • absolute gravity
  • continent
  • national geophysical data center
  • noaa
  • satellite orbits
  • north america
  • gravity
  • u.s. department of commerce
  • observed gravity
  • earth science
  • doc/noaa/nesdis/ngdc
  • gridded gravity
  • solid earth
  • doc/noaa/nesdis/ncei
  • gravitational field
  • control surveys
  • free air anomaly
  • geodetics/gravity
  • national centers for environmental information
  • reference systems

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