NODC Standard Product: US Navy Geosat altimeter Crossover Differences (XDRs) for the Geodetic Mission (8 disc set) (NODC Accession 0054498)

This accession contains a copy of the NODC eight CD-ROMs product set of the Geosat altimeter Crossover Differences data Records (XDRs) for altimeter data obtained between March 30, 1985 and September 30, 1986, the period known as Geosat's Geodetic Mission (GM). These data are in binary format.

The U.S. Navy Geosat altimeter mission lasted for nearly 5 years, from April 1985 to January 1990. Geophysical data records (GDRs) from the final 3 years, when the satellite was performing the exact repeat mission (ERM), were produced by NOAA's National Ocean Service and have been widely distributed. In contrast, GDRs from Geosat's first 18 months (April 1985 to September 1986), known as the geodetic mission, are classified because of military applications related to knowledge of the marine geoid. Only the altimetric heights are considered secret, however, and unclassified subsets of these data have been released. Another unclassified data type is the crossover difference. A crossover is defined as the intersection of the satellite ground track with itself. At this location, the two crossing passes (one ascending and one descending) provide independent sea level measurements at the same place but at different times. The difference of these two sea level measurements (a crossover difference) is not considered classified because the geopotential component of sea level is the same at the intersection of the two tracks and thus cancels. Crossover differences contain information about uncertainties in the satellite ephemeris and therefore enable correction of radial orbit error.

The Geosat altimeter crossover difference records (XDRs) contained on these CD-ROMs are documented in a NOAA handbook (Cheney et al. 1991b); see reference listing in the supplementary information field below. Although only the 18-month GM data are classified, XDRs have been constructed for the first 2.5 years of the Geosat mission, e.g., data from the GM plus the first year of the ERM. This was done to minimize the effect of the 5-week data gap (October 1 to November 8, 1986) between the two missions when the altimeter was off during orbit maneuvers. By computing crossovers for the entire 2.5-year period, continuous sea level time series can be derived.

These discs are no longer available from the NODC Online Store.
Cite as: Cheney, R. and US DOC; NOAA; National Ocean Service (2011). NODC Standard Product: US Navy Geosat altimeter Crossover Differences (XDRs) for the Geodetic Mission (8 disc set) (NODC Accession 0054498). Version 1.1. National Oceanographic Data Center, NOAA. Dataset. [access date]
Download Data
  • HTTPS (download)
    Navigate directly to the URL for data access and direct download.
  • FTP (download)
    These data are available through the File Transfer Protocol (FTP). You may use any FTP client to download these data.
Distribution Formats
  • Originator data format
Distributor DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
301-713-3277
NCEI.Info@noaa.gov
Dataset Point of Contact DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
301-713-3277
NCEI.Info@noaa.gov
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 a descriptive web page with download links.
Date(s)
  • publication: 2011-01-14
Edition: 1.1
Data Presentation Form: Digital table - digital representation of facts or figures systematically displayed, especially in columns
Dataset Progress Status Complete
Data Update Frequency: As needed
Supplemental Information:
REFERENCES

Cheney, R.E., W.J. Emery, B.J. Haines, and F. Wentz, 1991a: Recent improvements in Geosat altimeter data, EOS, 72 (51), 577-580.

Cheney, R.E., Doyle, N.S., Douglas, B.C., Agreen, R.W.,Miller, L., Timmerman, E.L. and D.C. McAdoo, 1991b: The complete Geosat altimeter GDR handbook, NOAA Manual NOS NGS-7, Rockville, MD, 79 pp.

Cheney, R.E., Douglas, B.C., and Miller, L., 1989: Evaluation of GEOSAT altimeter data with application to tropical Pacific sea level variability, J. Geophys. Res., 94, 4737-4747.

Cheney, R.E., Douglas, B.C., Agreen, R.W., Miller, L., Porter, D., and Doyle, N.S., 1987: GEOSAT altimeter geophysical data record user handbook, NOAA Tech. Memo. NOS NGS-46, Rockville, MD, 32 pp.

Cheney, R.E., Douglas, B.C., Agreen, R.W., Miller, L., Milbert, D., and Porter, D., 1986: The GEOSAT altimeter mission: A milestone in satellite oceanography, EOS, 67, 1354-1355.

Cheney, R.E. and Marsh, J.G., 1981: Oceanic eddy variability as measured by Geos 3 altimeter crossover differences, EOS, 62, 743-752.

Dobson, E.B., Wilkerson, J., Agreen, R., and Douglas, B., 1988: GEOSAT altimeter wind and wave data record user handbook, Johns Hopkins University Applied Physics Laboratory Tech. Report S1R88U-009, Laurel, MD, 28 pp.

Emery, W.J., G.H. Born, D.C. Baldwin, and C.L. Norris, 1990: Satellite-derived water vapor corrections for Geosat altimetry, J. Geophys. Res., 95 (C3), 2953-2964.

Fu, L.-L. and Chelton, D.B., 1985: Observing large-scale temporal variability of ocean currents by satellite altimetry: With application to the Antarctic Circumpolar Current, J. Geophys. Res., 90, 4721-4739.

Marsh, J.G. and Williamson, R.G., 1980: Precision orbit analyses in support of the Seasat altimeter experiment, J. Astron. Sci., 28, 345-369.

Milbert, D., Douglas, B.C., Cheney, R.E., and Miller, L., 1989: Calculation of sea level time series from non-collinear GEOSAT altimeter data, Mar. Geod., 12, 287-302.

Miller, L., Cheney, R.E., and Milbert, D., 1986: Sea level time series in the equatorial Pacific from satellite altimetry, Geophys. Res. Lett., 13, 475-478.

Minster J-F., D. Jourdan, E. Normant, C. Brossier, and M.C. Gennero, 1992: An improved SSMI water vapor correction for Geosat altimeter data, J. Geophys. Res., 97, 17859-17872.

Sandwell, D.T., Milbert, D.G., and Douglas, B.C., 1986: Global nondynamic orbit improvement for altimetric satellites, J. Geophys. Res., 91, 9447-9451.

Tai, C.-K., 1991: How to observe the gyre to global scale variability in satellite altimetry: Signal attenuation by orbit error removal, J. Atmos. Ocean. Tech., 8, 271-288.

Tai, C.-K., 1989: Accuracy assessment of widely used orbit error approximations in satellite altimetry, J. Atmos. and Ocean. Technol., 6, 147-150.

Wentz, F., 1989: User's manual for the collocated Geosat SSM/I tape, Tech. Rep. 083189, Remote Sensing Systems, Santa Rosa, CA.
Purpose: Basic research
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 data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
Resource Provider(s)
  • Robert Cheney
  • US DOC; NOAA; National Ocean Service (NOS)
Publisher(s)
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NODC > National Oceanographic Data Center, NESDIS, NOAA, U.S. Department of Commerce
Time Period: 1985-03-30 to 1986-09-30
Spatial Bounding Box Coordinates:
N: 72
S: -72
E: 180
W: -180
Spatial Coverage Map:
Theme keywords NODC DATA TYPES THESAURUS NODC OBSERVATION TYPES THESAURUS WMO_CategoryCode
  • oceanography
Global Change Master Directory (GCMD) Science and Services Keywords
  • EARTH SCIENCE > OCEANS > OCEAN WAVES
  • EARTH SCIENCE > OCEANS > OCEAN WAVES > WAVE HEIGHT
Data Center keywords Global Change Master Directory (GCMD) Data Center Keywords
  • DOC/NOAA/NESDIS/NODC > National Oceanographic Data Center, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NOS > National Ocean Service, NOAA, U.S. Department of Commerce
NODC COLLECTING INSTITUTION NAMES THESAURUS NODC SUBMITTING INSTITUTION NAMES THESAURUS
Platform keywords NODC PLATFORM NAMES THESAURUS Global Change Master Directory (GCMD) Platform Keywords
  • GEOSAT > Geodetic Satellite
Instrument keywords NODC INSTRUMENT TYPES THESAURUS
Place keywords NODC SEA AREA NAMES THESAURUS Global Change Master Directory (GCMD) Location Keywords
  • GEOGRAPHIC REGION > GLOBAL OCEAN
Keywords NCEI ACCESSION NUMBER
Use Constraints
  • Cite as: Cheney, R. and US DOC; NOAA; National Ocean Service (2011). NODC Standard Product: US Navy Geosat altimeter Crossover Differences (XDRs) for the Geodetic Mission (8 disc set) (NODC Accession 0054498). Version 1.1. National Oceanographic Data Center, NOAA. Dataset. [access date]
Access Constraints
  • 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
  • Digital data may be downloaded from NCEI at no charge in most cases. For custom orders of digital data or to obtain a copy of analog materials, please contact NCEI Information Services for information about current fees.
Lineage information for: dataset
Processing Steps
  • 2011-01-14T18:21:35 - NCEI Accession 0054498 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.
Last Modified: 2017-01-29T00:15:23
For questions about the information on this page, please email: NODC.DataOfficer@noaa.gov