IMPROVED ALONG-TRACK RESOLUTION OF NEARLY REPEATED SATELLITE ALTIMETER DATA

Using a cross-track averaging technique in combination with along-track low pass filtering of satellite radar altimeter profiles, the along-track spatial wavelength resolution capability of the mean sea level for a set of nearly repeated altimeter tracks can be improved. This is demonstrated with Geos-3 data, for which we have improved the along-track wavelength resolution from over 100 km to 40 km. Compared with more recent satellites with large track spacing at low and mid latitudes, Geos-3 can still contribute to gravity field determination at latitudes below 40 degrees in regions with good Geos-3 data coverage. The method presented here suggests a way to process data sets from e.g., ERS-1 168-day cycle, Geosat GM data, or future altimeter missions where cross-track spacing is less than half the along-track resolution.