Prediction of radar backscatter for gravity-capillary waves with precise spatial and temporal measurements

Water waves were generated mechanically in the laboratory to investigate the electromagnetic response for a roughened air-water interface. A FM-CW radar operating at 3 cm wavelength was used to monitor the water surface while precise concurrent nonintrusive surface elevation profiles were recorded using high-speed video imaging. A wavemaker produced wave frequencies of 6-12 Hz in increments of 0.05 Hz, a regime replete with internal resonances of the water waves. Precise surface and radar backscatter measurements facilitate the direct comparison between surfaces of known roughness properties and scattered fields. An analytical method was used to predict Bragg scattering. Measured versus predicted radar backscatter results show the ability to predict radar backscatter precisely