Improvement in the estimation of dominate wavenumber and direction from spaceborne SAR image spectra when corrected for ocean surface movement

Because a synthetic aperture radar (SAR) is a Doppler device, ocean surface movement can degrade a SAR ocean image. Ocean surface movement causes the redistribution of apparent radar cross section in a SAR image to neighboring image elements. It is demonstrated in this paper that this aspect of SAR imaging can be treated as a simple resolution loss in a linear system. Such an approach explains the falloff in response at high azimuth wavenumbers experienced in SAR image spectra. More importantly, this approach allows for a straightforward method to alleviate the problem of ocean surface motion. Correction of SAR image spectra using a linear systems approach results in SAR image spectra in which the locations in wavenumber-space of surface wave spectral peaks are more consistent with the estimated location of storm sources than are the locations of peaks from uncorrected spectra.