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Dataset Overview | National Centers for Environmental Information (NCEI)

NODC Standard Product: US Navy Geosat altimeter geophysical data records (GDRs) for the Geodetic Mission (NCEI Accession 0053782)

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This dataset contains a complete copy of an NODC four CD-ROM product set containing all of NOAA's geophysical data records (GDRs) for the Geosat altimeter data obtained between March 30, 1985 and September 30, 1986 (the period known as Geosat's Geodetic Mission (GM)). This CD-ROM set supersedes a previous release of the Geodetic Mission GDRs, which was limited to the region south of 30 S. These data are in binary format.

From March 1985 until January 1990 the U.S. Navy satellite Geosat generated a new dataset with unprecedented spatial and temporal coverage of the global oceans. Designed and built at the Johns Hopkins University Applied Physics Laboratory, Geosat carried a radar altimeter which produced profiles of sea level, wave height, and wind speed along the satellite ground track. Such records have application in areas of geodesy, geophysics, ocean dynamics, and global climate research.

The acronym Geosat was derived from geodetic satellite because its primary mission was to obtain a high-resolution description of the marine geoid. This goal was achieved during the first 18 months, known as the geodetic mission (GM), which extended from March 30, 1985 to September 30, 1986. The GM was based on a 23-day, near-repeat orbit which was permitted to drift, ultimately producing a tightly spaced ground track pattern. At the end of 18 months, the spacing between adjacent tracks at the equator was approximately 5 km, and at 60 degrees latitude only 2 or 3 km.

Because of their military significance, GM altimeter data were initially classified, but in 1992 the U.S. Navy approved the release of all GM altimetry in the latitude band 30 S to 72 S. In June, 1995, the remainder of the GM data were declassified by the Navy. This CD-ROM set contains NOAA's version of these declassified global GM GDRs. For a description of the content and format, refer to the Complete Geosat Altimeter GDR Handbook, Cheney et al. (1991b).
  • Cite as: Cheney, Robert E.; NOAA National Ocean Service (2009). NODC Standard Product: US Navy Geosat altimeter geophysical data records (GDRs) for the Geodetic Mission (NCEI Accession 0053782). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/0053782. Accessed [date].
gov.noaa.nodc:0053782
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Distribution Formats
  • Originator data format
Ordering Instructions Contact NCEI for other distribution options and instructions.
Distributor NOAA National Centers for Environmental Information
+1-301-713-3277
NCEI.Info@noaa.gov
Dataset Point of Contact NOAA National Centers for Environmental Information
ncei.info@noaa.gov
Time Period 1985-03-30 to 1986-09-30
Spatial Bounding Box Coordinates
West: -180
East: 180
South: -72
North: 72
Spatial Coverage Map
General Documentation
Associated Resources
  • Data Records derived from GEOSAT Geodetic Mission (GM) and Exact Repeat Mission (ERM) data from 30 March 1985 to 31 December 1989
    • NCEI Collection
      Navigate directly to the URL for data access and direct download.
  • Parent ID (indicates this dataset is related to other data):
    • gov.noaa.nodc:GEOSAT-GM-ERM
Publication Dates
  • publication: 2009-05-15
Data Presentation Form Digital table - digital representation of facts or figures systematically displayed, especially in columns
Dataset Progress Status Complete - production of the data has been completed
Historical archive - data has been stored in an offline storage facility
Data Update Frequency As needed
Supplemental Information
It should be noted that whereas the GM GDRs represent a relatively complete record of the data over the ocean, the same is not true for global land and ice surfaces. As discussed in the Complete Geosat Altimeter GDR Handbook (Chapter III), the process of generating GDRs from the sensor data records (SDRs) included an editing step in which SDR flags were used to delete data when the altimeter was not tracking. This typically removed 40 percent of the global data, mostly over land and ice. In certain regions such as the Greenland ice sheet, however, the altimeter was able to maintain tracking on the relatively flat surface. Under these circumstances a significant amount of land/ice data were retained in the GM GDRs.
Purpose This dataset is available to the public for a wide variety of uses including scientific research and analysis.
Use Limitations
  • accessLevel: Public
  • Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
Dataset Citation
  • Cite as: Cheney, Robert E.; NOAA National Ocean Service (2009). NODC Standard Product: US Navy Geosat altimeter geophysical data records (GDRs) for the Geodetic Mission (NCEI Accession 0053782). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/0053782. Accessed [date].
Cited Authors
Contributors
Resource Providers
Publishers
Theme keywords NODC DATA TYPES THESAURUS NODC OBSERVATION TYPES THESAURUS WMO_CategoryCode
  • oceanography
Global Change Master Directory (GCMD) Science Keywords
Data Center keywords NODC COLLECTING INSTITUTION NAMES THESAURUS NODC SUBMITTING INSTITUTION NAMES THESAURUS Global Change Master Directory (GCMD) Data Center Keywords
Platform keywords NODC PLATFORM NAMES THESAURUS Global Change Master Directory (GCMD) Platform Keywords ICES/SeaDataNet Ship Codes
Instrument keywords NODC INSTRUMENT TYPES THESAURUS Global Change Master Directory (GCMD) Instrument Keywords
Place keywords NODC SEA AREA NAMES THESAURUS Global Change Master Directory (GCMD) Location Keywords
Keywords NCEI ACCESSION NUMBER
Use Constraints
  • Cite as: Cheney, Robert E.; NOAA National Ocean Service (2009). NODC Standard Product: US Navy Geosat altimeter geophysical data records (GDRs) for the Geodetic Mission (NCEI Accession 0053782). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://www.ncei.noaa.gov/archive/accession/0053782. Accessed [date].
Access Constraints
  • Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.
Fees
  • In most cases, electronic downloads of the data are free. However, fees may apply for custom orders, data certifications, copies of analog materials, and data distribution on physical media.
Lineage information for: dataset
Processing Steps
  • 2009-05-15T14:57:57Z - NCEI Accession 0053782 v1.1 was published.
Output Datasets
Lineage information for: repository
Processing Steps
  • 2015-04-22T00:00:00 - NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
Acquisition Information (collection)
Instrument
  • satellite sensor - altimeter
Platform
  • GEOSAT
Last Modified: 2024-03-02T15:19:04Z
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