NODC Standard Product: US Navy Geosat altimeter geophysical data records (GDRs) for the Geodetic Mission (NCEI Accession 0053782)
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).
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).
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].
Dataset Identifiers
ISO 19115-2 Metadata
gov.noaa.nodc:0053782
Download Data |
|
Distribution Formats |
|
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 |
|
Publication Dates |
|
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 |
|
Dataset Citation |
|
Cited Authors | |
Contributors | |
Resource Providers | |
Publishers |
Theme keywords |
NODC DATA TYPES THESAURUS
|
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 |
|
Access Constraints |
|
Fees |
|
Lineage information for: dataset | |
---|---|
Processing Steps |
|
Output Datasets |
|
Lineage information for: repository | |
---|---|
Processing Steps |
|
Acquisition Information (collection) | |
---|---|
Instrument |
|
Platform |
|
Last Modified: 2024-03-02T15:19:04Z
For questions about the information on this page, please email: ncei.info@noaa.gov
For questions about the information on this page, please email: ncei.info@noaa.gov