Doppler processing of coherent radar backscatter for ocean surface wave measurements

The technique for extracting wave period and wave direction from a navigation radar backscattering intensity is well developed but the determination of spectral density or wave height is hindered by the complex nature of the modulation transfer function. In contrast to backscattering intensity, Doppler velocity from coherent radar is the radial velocity of the scattering objects. Its oscillatory component is contributed by ocean waves. The spectral peak component of Doppler velocity is close to the peak wave period measured by a nearby buoy and the significant wave height can be accurately calculated. With radar range coverage on the order of ten dominant wavelengths, reliable assessment of peak wave period and significant wave height is achievable with radar data as short as one second. Wave direction can also be determined with a scanning system.