ESTIMATION OF SEA-SURFACE WINDS USING BACKSCATTER CROSS-SECTION MEASUREMENTS FROM AIRBORNE RESEARCH WEATHER RADAR

A technique is presented for estimation of sea-surface winds using bac kscatter cross-section measurements from an airborne research weather radar. The technique is based on an empirical relation developed for u se with satellite-borne microwave scatterometers which derives sea-sur face winds from radar backscatter cross-section measurements. Unlike a scatterometer, the airborne research weather radar is a Doppler radar designed to measure atmospheric storm structure and kinematics. Desig ned to scan the atmosphere, the radar also scans the ocean surface ove r a wide range of azimuths, with the incidence angle and polarization angle changing continuously during each scan. The new sea-surface wind estimation technique accounts for these variations in incidence angle and polarization and derives the atmospheric surface winds. The techn ique works well over the range of wind conditions over which the wind speed-backscatter cross-section relation holds, about 2-20 m/s. The pr oblems likely to be encountered with this new technique are evaluated and it is concluded that most problems are those which are endemic to any microwave scatterometer wind estimation technique. The new techniq ue will enable using the research weather radar to provide measurement s which would otherwise require use of a dedicated scatterometer.