Charting the Remote Southern Oceans With Geosat Altimetry

The Geosat satellite altimeter has mapped the marine gravity field over nearly all of the world's oceans to a high accuracy and high spatial resolution. In the wavelength band 15 to 200 km, variations in gravity anomaly are highly correlated with seafloor topography. Since many southern ocean areas are sparsely surveyed, these new Geosat data reveal many previously unsurveyed features such as seamounts and fracture zones. The objectives of our proposed research were to: (1) Develop a method of combining geoid heights (or gravity anomalies) with shipboard profiles in order to improve bathymetric charts. (2) Evaluate the method by comparing bathymetric predictions with measured seafloor depths in two areas south of 60 deg S. (3) Produce an improved unclassified version of the Navy's standard bathymetric data base of the southern ocean (i.e. between 60 deg S and 72 deg S). (4) Produce an improved classified version of the Navy's standard bathymetric data base of the southern hemisphere (i.e. south of the equator). The original cost of the proposed research to be conducted over a 3 year period was $485,237. Due to a budget cut at DMA our budget was reduced to $40,000. Thus we completed only a small fraction of the proposed research as outlined in the attached progress reports.