Numerical Scattering Simulations from Time-evolving Ocean-like Surfaces at L- and X-band: Doppler Analysis and Comparisons with a Composite Surface Analytical Model1

Direct numerical simulations of sea surface scattering are used to evaluate the accuracy of a recently proposed analytical model for ocean-generated Doppler spectra. Comparisons are performed for backscattering at incidence angles varying from near-nadir to low grazing at Land X-bands. Doppler centroids predicted by the model show, as expected, large discrepancies close to nadir and grazing directions. However, even for moderate incidence angles, a disagreement of 1025% is observed, especially at X-band. At present, the reason for this deviation is not well understood. The Doppler widths, however, show good agreement across the broad range of incidence angles.