SCATTEROMETRY OF A DROP IMPACT ON A SALT-WATER SURFACE

Experiments of scatterometry at 13.5 and 36 GHz, VV polarization have been conducted in the new Rain-Sea Interaction Facility at NASA Wallop s. Radar backscatterings of rain drop impacts on a salt water surface have been measured with an incidence angle of 30 degrees for various d ropsizes at terminal fall velocity. Results for 2.8 mm drops are prese nted. Surface features were imaged by an ultra high speed digital came ra synchronized with the radar data acquisition. Backscattered powers from crowns, craters, stalks and ringwaves were measured. These measur ements confirm that for the scatterometric configuration under conside ration, ringwaves are the dominant scattering contribution and that st alks scattering is much smaller but not negligible.