Global Seafloor Topography from Satellite Altimetry

Walter H.F. Smith (NOAA Geosciences Laboratory)
David T. Sandwell (Scripps Institution of Oceanography)
Primary funding from the National Science Foundation

Posters and Atlas:

• Poster - Measured and Estimated Seafloor Topography
  World Data Center for Geophysics & Marine Geology, Boulder
  Research Publication RP-1, from SIO & NGDC, IT'S HERE!
• Poster - Gravity Anomalies of the Global Seafloor - available from SIO
• Poster - Predicted topography 30-72 degrees South Latitude available from NGDC
• Poster - Gravity Anomalies 30-72 South Latitude available from NGDC
• Poster - Gravity anomalies 60-72 South Latitude available from NGDC
• Gravity Atlas of the Southern Ocean from NGDC
• Posters - of Global Relief and other Data from NGDC.

Data:

• CD-ROM, ETOPO2 - Global 2 minute gridded topography & bathymetry
• CD-ROM, Predicted Topography data from 30-72 degrees South Latitude available from NGDC
• CD-ROM, Gravity anomaly data from 30-72 South Latitude included on the Global Relief CD-ROM data set available from NGDC
• CD-ROM, GEOSAT data, from the National Oceanographic Data Center
• Analyses of GEOSAT & ERS data from the NOAA Laboratory for Satellite Altimetry
• Bathymetry & relief data from NGDC
• On-line Data Including GTOPO30 Land Data! from SIO
• ERS data from the European Space Agency

On-Line Imagery:

• Global Relief images incorporating Smith & Sandwell Bathymetry
• Image viewing from NOAA's Satellite Altimetry Lab
• Imagery by NOAA's Walter Smith
• On-line Images including GTOPO30 Land Data at SIO
• More globes generated from the measured & estimated seafloor topography data at NGDC

Related Reports, Articles, and Links

• Global Sea Floor Topography from Satellite Altimetry and Ship Depth Soundings,
  W.H. Smith and D.T. Sandwell, 1997, Science Magazine, vol. 277, issue 5334
• Exploring the Ocean Basins with Satellite Altimetry,
  Sandwell and Smith, updated images 12/96
• (no longer active) Discovery Channel - Satellites See More of the Seafloor
• (no longer active) Earth Magazine article, "The Seafloor Laid Bare"
  featuring the Smith & Sandwell image
• Global Seafloor Topography from Satellite Altimetry, Walter H.F. Smith and David T. Sandwell,
  abstract, AGU 1996 Fall Meeting, San Francisco, CA.
• Predicted and Measured Seafloor Topography, Walter H.F. Smith, David T. Sandwell, and Stuart Smith
• Global Bathymetric Prediction for Ocean Modelling and Marine Geophysics, David T. Sandwell and Walter H.F. Smith
• Marine Gravity Anomaly from Geosat and ERS-1 Satellite Altimetry, Sandwell, David T., and Walter H.F. Smith,
  J. Geophysical Res. 102, 10,039-10,054, 1997.
• McGraw-Hill Yearbook of Science and Technology, p. 178-180, 1995.
• Sandwell, D. T., Geophysical Applications of Satellite Altimetry, Reviews of Geophysics Supplement, p. 132-137, 1990.
• More Estimated Topography Images, from different views of the globe

On Monday, October 23, 1995 NOAA's Geoscience Laboratory and the Scripps Institution of Oceanography (SIO) held a joint press conference to describe a new image of ocean floor structures made from recently available satellite data. The map was derived from satellite altimeter data collected by the European Space Agency and the US Navy. NOAA's National Oceanographic Data Center distributes the raw data from the US Navy's GEOSAT satellite. The data can be processed to reveal tiny changes in the pull of gravity. These changes are usually caused by mountains and valleys on the ocean floor, so gravity maps are useful in revealing the geology of the sea floor. However, gravity is not topography (depth). It is possible to predict depths by combining gravity data with ship surveys of depth. The authors are currently analyzing the available data to produce a database of inferred or "predicted" topography. Although the image displayed has been referred to by the press as a "Detailed map of ocean floor" it is actually a preliminary map of global seafloor gravity anomalies. Copies of this (approximately 3 x 5 foot) gravity map are available from SIO (see link above under Posters).

A published map of The Measured and Estimated, or "Predicted," Global Seafloor Topography was completed and made available in mid-1997 (see top of this page).