Boundary-Layer Meteorology

, Volume 13, Issue 1–4, pp 393–404 | Cite as

The experimental oceanographic satellite Seasat-A

  • James A. Dunne


A Seasat-A Project was conceived and is being implemented to establish the utility of an array of microwave instruments in space for oceanic research and marine technology. The instruments include: a short-pulse radar altimeter, a wind-field scatterometer, an experimental synthetic-aperture imaging radar, a scanning multifrequency microwave radiometer, and a supporting visual and infrared radiometer. All weather, day-night measurements of sea-surface temperature, surface wind speed and direction, sea state and directional wave spectra will be made, the latter over limited areas and times because of operational limitations on the synthetic-aperture-radar instrument. Highly precise (&<0.1 m) range information from the radar altimeter, in combination with an accurate satellite emphemeris, will be used to infer dynamic departures of sea level from the marine geoid produced by tides, currents, and storm surges. Sea ice will be observed by the synthetic-aperture radar, radar altimeter and the scanning multifrequency microwave radiometer, with particular emphasis on demonstrating their capability to determine polar ice coverage, dynamics and navigability.

The satellite will be launched into a high-inclination (108 °), non-sun-synchronous, nearly-circular 800 km orbit in May of 1978. The orbit is such that a dense network traced out by the subsatellite point (18.5-km equatorial separation of ascending orbits) will be obtained in 152 days for geodesy. The satellite is designed for a minimum lifetime of one year; with expendables, including orbit adjust capability, for three.

All data, except those obtained from the synthetic-aperture radar, will be collected globally, and returned, as measured, first by a 25 kbps data stream, and then after playback at a rate of 800 kbps from the on-board tape recorder. Synthetic-aperture radar data will be returned in real time only, over a 20-MHz analog telemetry link. We expect that satellite data will be distributed through the National Oceanic and Atmospheric Administrations Environmental Data Service. Processed data are expected to be generally available through this agency within a very few months of launch, following preliminary assessment of instrument operation and evaluation of performance.


Radar Surface Wind Speed Microwave Radiometer Radar Altimeter Infrared Radiometer 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. Apel, J. R., (Ed.): 1972, ‘Sea Surface Topography from Space’, Vols. 1 and 2, Tech. Rep. ERL 228, Nat. Oceanic and Atmos. Admin., Boulder, Colo. U.S.A.Google Scholar
  2. Apel, J. R. and Byrne, H. M.: 1974, ‘Oceanography and the Marine Geoid’,Applications of Marine Geodesy, Marine Technology Society, Washington,. D.C., p. 59.Google Scholar
  3. Apel, J. R. and Siry, J. W.: July, 1974, ‘A Synopsis of Seasat-A Scientific Contributions’,Seasat-A Scientific Contributions, NASA, Washington, D.C.Google Scholar
  4. Apel, J. R.: 1976, ‘Ocean Science from Space’,Trans. Amer. Geophys. Union 57, 612–624.Google Scholar
  5. Barncastle, L.: 1971, ‘ITOS Meteorological Scanning Radiometer’,Proc. Electro-Optics '71 West, 164.Google Scholar
  6. Brown, W. E., Jr., Elachi, C., and Thompson, T. W.: 1976, ‘Radar Imaging of Ocean Surface Patterns’,J. Geophys. Res. 81, 2657.Google Scholar
  7. Campbell, W. J., Weeks, W. F., Ramseier, R. O., and Gloersen, P.: 1975, ‘Geophysical Studies of Floating Ice by Remote Sensing’,J. Glaciol. 15, 305–328.Google Scholar
  8. Cardone, V. J. and Pierson, W. J.: 1975, ‘The Measurement of Winds over the Ocean from Skylab with Application to Measuring and Forecasting Typhoons and Hurricanes’,Proc. Eleventh Int. Symp. on Space Techn. and Sci., Tokyo.Google Scholar
  9. Dunne, J. A.: 1976, ‘The Seasat-A Project: An Overview’,Oceans 76 Conference Record, p. 10A-1.Google Scholar
  10. Gloersen, P. and Salomonson, V. V.: 1975, ‘Satellites: New Global Observing Techniques for Ice and Snow’,J. Glaciol. 15, 373.Google Scholar
  11. Gloersen, P. and Barath, F. T.: 1976, ‘The Seasat-A Scanning Multichannel Microwave Radiometer’,Oceans '76 Conference Record, p. 10C-1.Google Scholar
  12. Grantham, W. L., Bracalente, E. M., Jones, W. L., Shrader, J. H., Schroeder, L. C., and Mitchell, J. L.: 1975, ‘An Operational Satellite Scatterometer for Wind Vector Measurements over the Ocean’, NASA Tech. Memo X-72672, Goddard Space Flight Centre, Greenbelt, Md.Google Scholar
  13. Grantham, W. L. and Jones, W. L.: 1976, ‘The Seasat-A Microwave Scatterometer’,Oceans '76 Conference Record, p. 10D-1.Google Scholar
  14. Hendershott, M. C., Munk, W. H., and Zetler, B. D.: July 1974, ‘Ocean Tides from Seasat-A’,Seasat-A Scientific Contributions 54, NASA, Washington, D.C.Google Scholar
  15. Jones, W. L., Schroeder, L. C., and Mitchell, J. L. 1976, ‘Aircraft Measurements of the Microwave Scattering Signature of the Ocean’,IEEE Trans on Antennas Propag. AP-25, 52–60 (in press).Google Scholar
  16. MacArthur, J. L.: 1976, ‘Design of the Seasat-A Radar Altimeter’,Oceans '76 Conference Record, p. 10B-1.Google Scholar
  17. Marsh, J. G., Lerch, F. J., and Vincent, S. F.: 1973, ‘The Geoid and Free Air Gravity Anomalies Corresponding to the Gem-4 Earth Gravitational Model’,NASA/Goddard Space Flight Center Rept. S-592-73-58, Greenbelt, Md.Google Scholar
  18. McGoogan, J. T., Leitao, C. D., and Wells, W. T.: 1975, ‘Summary of Skylab S-193 Altimeter Altitude Results’, NASA Tech. Memo X-69355, Goddard Space Flight Center, Greenbelt, Md.Google Scholar
  19. McGoogan, J.: 1975, ‘Satellite Altimetry Applications’,IEEE Transactions on Microwave Theory and Technology MMT-23, (12), 970–978.Google Scholar
  20. Miller, L. S. and Brown, G. S.: 1974, ‘Engineering Studies Related to the GEOS-C Radar Altimeter’,NASA CR-137462.Google Scholar
  21. NASA, Wallops Flight Center: 1974, ‘GEOS-C Mission Plan’,Wallops Flight Center Rept. TK-6340-001, Wallops Island, Va.Google Scholar
  22. Pierson, W. J., Cardone, V. J., and Greenwood, J. A.: 1974, ‘The Applications of Seasat-A to Meteorology’, NOAA/NESS/SPOCTechnical Report, Grant No. 04-4-158-11, The University Institute of Oceanography, City University of New York.Google Scholar
  23. Ross, D. B. and Cardone, V. J.: 1974, ‘Observations of Oceanic White Caps and Their Relation to Remote Measurements of Surface Wind Speed’,J. Geophys. Res. 79, 444.Google Scholar
  24. Thompson, T. W., Brown, W. E., and Elachi, C.: 1976, ‘The Seasat-A Imaging Radar’,Oceans '76 Conference Record, p. 10E-1.Google Scholar
  25. Walsh, E. J.: 1974, ‘Analysis of Experimental NRL Radar Altimeter Data’,Radio Sci. 9, 711.Google Scholar

Copyright information

© D. Reidel Publishing Company 1978

Authors and Affiliations

  • James A. Dunne
    • 1
  1. 1.Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaUSA

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