Time series of sea surface height anomaly as measured by inverted echo sounders with pressure gauges (IES/PGs) and Geosat altimetry are compared at six locations in the northwest Atlantic near 40 ¿N, 55 ¿W. Three IES/PG sites lay along each of two adjacent Geosat-Exact Repeat Mission ground tracks. Better agreement was found along the westernmost ground track; pressure sensor noise is the probable source of the larger errors along the easternmost ground track. The overall correlation is 0.78; along the westernmost ground track it is 0.91. Decorrelation scales are about 100 km along track and about 5 days. Uncorrelated errors dominate, but along the westernmost ground track, IES/PG-derived sea surface height variability is systematically smaller than that derived from Geosat data; this factor, determined by regression analysis, is about 0.81. However, a consistent adjustment of IES calibration removes the systematic discrepancy.