Geosat/ERM altimeter data analysis for the determination of global oceanic mesoscale variability.

摘要

Obtaining a basic description of the global mesoscale variability is fundamental to an improved understanding of ocean dynamics. Satellite altimetry which measures the distance between the spacecraft and the sea surface is becoming an important tool for acquiring global, synoptic measurements of the dynamic topography of the oceans. The radial orbit error has been the major limitation to the satellite altimeter oceanographic studies. The goal of this dissertation is to develop methods for reducing radial orbit error and to apply these methods to Geosat altimeter data.;The conventional crossing arc technique has been widely applied to satellite geodesy and oceanography. An efficient and generalized method is developed here which is applicable to both single and dual satellite crossover measurements. Evaluations of the radial orbit error show that the operational Geosat Exact Repeat Mission (ERM) orbits have 3 ;Based on this orbit error analysis, a new technique has been developed for extracting global mesoscale variability from collinear satellite altimeter profiles which have large radial orbit error. Long wavelength radial orbit error is suppressed by taking the derivative of each altimeter profile. The resulting mean sea surface slope profiles, averaged from 22 repeat slope profiles, have a precision about 0.1 ;The global rms variability map shows previously unknown spatial details that are highly correlated with sea floor topography. At mid-latitudes, the variability is generally high in deep water (