Three dimensional spectra of X-band Doppler radar backscatter from the ocean surface

Time-series of spatial wave images acquired with an imaging Doppler radar are used to determine the wavenumber-frequency auto- and cross-power spectra of radar backscattered power and Doppler velocity. The frequency and spatial resolutions obtained are sufficient to resolve both wind-waves and swell. Features evident in the spectra include those due to both linear gravity waves and other nonlinear waves as well as currents. The authors observe high peak coherence values in three dimensional spectra, often exceeding 0.8 for dominant wave features over several frequency bands