High Resolution Global Bathymetry from Satellite Altimetry, with a detailed view of the Arctic Ocean.
Ole Andersen(1) and Per Knudsen(1)
Danish National Space Center,
Juliane Maries Vej 30,
Knowledge about the depth of the oceans is important to practically all marine activities. Satellite altimetry has earlier been recognized as a source of information that can provide valuable information about the bathymetry along with direct observations from ship using i.e. multibeam bathymetry. With its very dense geographical distribution, the altimeter data from the GEOSAT and ERS-1 Geodetic Missions has a high potential for recovering especially the shorter spatial wavelength. The global high-resoluiton altimetric marine gravity field (DNSC05) is used in an attempt to enhance the details of the ETOPO5 5' by 5' bathymetry model on 1/30 degree resolution.
A bathymetric model is created using ETOPO5 dataset for wavelengths longer than 200 km. For the shorter wavelength (10-100 km) a regression is made between the existing topographic information and the downward continued gravity field anomalies assuming a flat transfer function between the two quantities.
Intermediate wavelength (50-200) km was finally predicted using the integrated inversion method based on Parker's formula, for the relationship between gravity and bathymetry. A modified version of this approach was initially for global bathymetric prediction by Knudsen and Andersen (1996). The prediction of bathymetry is confined to depth greater than 250 meters, to avoid problems close to the coast where the accuracy of the gravity field modeling from satellite altimetry is known to degrade.