On using significant wave height and radar cross section to improve radar altimeter measurements of wind speed

Abstract

Wind blowing across the ocean surface generates small, centimeter scale roughness. The radar cross section (RCS) measured by spaceborne, nadir‐looking altimeters operating at about 13.5 GHz is responsive to this roughness. Present altimeter algorithms use RCS to infer wind speed. We compare Geosat altimeter estimates of wind speed and nearly coincident estimates from NOAA data buoys to determine whether altimeter algorithms can be improved by using more of the information available from altimetry. We find that a marginal improvement in wind speed retrievals can be obtained by including additional RCS information and significant wave height in the retrieval algorithm. Perhaps most important, results also suggest that wind‐wave growth is suppressed in the presence of preexisting ocean swell.