RECOVERY OF THE SEA-LEVEL SIGNAL IN THE WESTERN TROPICAL PACIFIC FROM GEOSAT ALTIMETRY

In a previous paper we pointed out deficiencies in our Geosat results for the western tropical Pacific (130°E to 160°E), where less than half of the sea level signal amplitude was recovered. The suspected cause was the quadratic orbit error model, which, together with the relatively short arcs used, resulted in severe signal damping. We have since reprocessed the first 2.5 yr of Geosat data for the western region using longer arcs extending into the southern ocean together with a linear orbit error model. Results confirm our hypothesis with regard to orbit error and at the same time suggest that other error sources such as water vapor were much less significant. These new sea level records provide an improved description of the western Pacific prior to and during the 1986-1987 El Nino. -from Authors