Gravity Anomalies and Estimated Topography Derived from Satellite Altimetry

Metadata Updated: February 7, 2018

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.

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Dates

Metadata Date September 25, 2017
Metadata Created Date September 26, 2015
Metadata Updated Date February 7, 2018
Reference Date(s) January 1, 1994 (publication)
Frequency Of Update NOT UPDATED

Metadata Source

Harvested from NOAA CSW Harvest Source

Additional Metadata

Resource Type Dataset
Metadata Date September 25, 2017
Metadata Created Date September 26, 2015
Metadata Updated Date February 7, 2018
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
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
Guid gov.noaa.ngdc.mgg.geophysics:G00978
Harvest Object Id 43f757fe-9420-4224-b85a-7caf71275493
Harvest Source Id 2aed8e29-fc5b-4cde-aa66-fb1118fd705e
Harvest Source Title NOAA CSW Harvest Source
Licence
Metadata Language
Metadata Type geospatial
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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