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Gravity Anomalies and Estimated Topography Derived from Satellite Altimetry

Metadata Updated: October 18, 2024

In many areas of the global ocean, the depth of the seafloor is not well known because survey lines by ships are hundreds of kilometers apart. Satellites carrying radar altimeters have measured the shape of the ocean along tracks only 3-4 km apart, and from these data we can make very accuratore (+/-3mGal) and high resolution (15km) maps of the marine gravity field. The gravity field mimics the seafloor topography in the 15-160 km wavelength band if sediment cover on the ocean floor is thin. Long-wavelength (greater than 160 km) topography is isostatically compensated and is not correlated with the gravity field. In addition, the satellite gravity field and the available depth measurements were used to determine the correlation between gravity and the seafloor topography. By applying this correlation to the gravity field we predict seafloor topography in the 15-160 km wavelength band. This topography is combined with a long-wavelength component estimated directly from ship depth measurements. The result reveals many new features and is within +/- 100m of actual depths in many cases. The Predicted Seafloor Topography derived from the depths estimated from Satellite Altimetry in combination with measured trackline bathymetry is an inferred data set and is not true bathymetry. It is, however, the best estimate of seafloor topography available resulting from satellite gravity data and actual ship depth measurements. These data are intended for scientific research and should not be used for navigational purposes. Additional software is required in order to manipulate the data or produce your own graphic images. Poster and CD-ROM products are available for both gravity anomaly and estimated seafloor topography of several regions. Please refer to URL https://www.ngdc.noaa.gov/mgg/announcements/announce_predict.html for more information, and to download sample images.

Access & Use Information

License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Dates

Metadata Date September 25, 2017
Metadata Created Date October 18, 2024
Metadata Updated Date October 18, 2024
Reference Date(s) January 1, 1994 (publication)
Frequency Of Update NOT UPDATED

Metadata Source

Harvested from NGDC MGG Geophysics

Additional Metadata

Resource Type Dataset
Metadata Date September 25, 2017
Metadata Created Date October 18, 2024
Metadata Updated Date October 18, 2024
Reference Date(s) January 1, 1994 (publication)
Responsible Party DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce (Point of Contact)
Contact Email
Guid gov.noaa.ngdc.mgg.geophysics:G00978
Access Constraints 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., Use Constraints: None, Access Constraints: No Constraints
Bbox East Long 180.0
Bbox North Lat 72.0
Bbox South Lat -72.0
Bbox West Long -180.0
Coupled Resource
Frequency Of Update NOT UPDATED
Harvest Object Id cb9a97bc-e093-41cb-94c1-e2f4e3d7f3f8
Harvest Source Id 80dfcf5d-5e08-457e-83e4-cfc696e378bc
Harvest Source Title NGDC MGG Geophysics
Licence
Lineage
Metadata Language eng; USA
Metadata Type geospatial
Old Spatial {"type": "Polygon", "coordinates": [[[-180.0, -72.0], [180.0, -72.0], [180.0, 72.0], [-180.0, 72.0], [-180.0, -72.0]]]}
Progress completed
Spatial Data Service Type
Spatial Reference System
Spatial Harvester True
Temporal Extent Begin 1978-07-01
Temporal Extent End 1978-10-30

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