A Method To Extend Geosat's Altimetric Synthetic Geoid From The Gulf Stream To The Sargasso Sea

Abstract

Using Geosat’s altimetric data a synthetic geoid was constructed and validated in the Gulf Stream meander and ring region. A method to extend this procedure from the Gulf Stream meander region south into the Sargasso Sea is proposed. The synthetic geoid was calculated by subtracting an independent estimate of the oceanographic mean from the altimetric mean sea surface. The resultant synthetic geoid was used to compute absolute dynamic topography from Geosat. The dynamic topography computed from the altimeter and in situ measurements was compared. The agreement was excellent with an rms difference less than 10 cm. Since the Sargasso Sea does not exhibit the large dynamic ranges that were evident in the Gulf Stream meander region, a zero mean in this area is proposed as the independent oceanographic mean. The resulting synthetic geoid can then be used to compute the dynamic heights in the Sargasso Sea as well as in the Gulf Stream meander region. GEOSAT, ALTIMETER, ]LIESOSCALE, GULF STREAM