SEA-SURFACE HEIGHT FLUCTUATIONS OBSERVED SIMULTANEOUSLY WITH INVERTEDECHO SOUNDERS AND GEOSAT

Time series of sea surface height anomaly as measured by inverted echo sounders with pressure gauges (IES/PGs) and Geosat altimetry are comp ared at six locations in the northwest Atlantic near 40-degrees-N, 55- degrees-W. Three IES/PG sites lay along each of two adjacent Geosat-Ex act Repeat Mission ground tracks. Better agreement was found along the westernmost ground track; pressure sensor noise is the probable sourc e of the larger errors along the easternmost ground track. The overall correlation is 0.78; along the westernmost ground track it is 0.91. D ecorrelation scales are about 100 km along track and about 5 days. Unc orrelated errors dominate, but along the westernmost ground track, IES /PG-derived sea surface height variability is systematically smaller t han that derived from Geosat data; this factor, determined by regressi on analysis, is about 0.81. However, a consistent adjustment of IES ca libration removes the systematic discrepancy.