Radar altimeters of great precision (≈10 cm), such as the one that flew on the SEASAT satellite, are capable of measuring the small oceanic height variations associated with geostrophic ocean currents. An experiment was concluded in the Kuroshio Current east of Japan, verifying this capability. Air-expendable bathythermographs (AXBT's) were dropped to coincide with the SEASAT subtract during flights on September 25 and October 5 and 13, 1978. Changes in surface dynamic height between flights were inferred from the AXBT data. They agreed generally to within ¿10 cm of height changes observed in the altimeter data.