Modeling of Ku-band backscatter from sea surface with wave breaking for 30-60° incidence angles

Abstract The present study constructs a Ku-band radar backscattering model for rough sea surfaces with wave breaking by incorporating the influence of steep waves and sea foam, which are two derivatives associated with wave breaking, into the classical two-scale model (TSM). The distribution and proportion of steep waves and sea foam in the sea surface at different wind speeds are determined by linearly fitting the proposed model to the NSCAT4 geophysical model function. The performance of our proposed model in predicting HH and VV NRCS at different wind speeds and incidence angles in upwind and crosswind directions is evaluated by comparing them with the reference NSCAT4 NRCS as well as those predicted by TSM. The results demonstrate that the NRCS predicted by our model agrees well with the NSCAT4 NRCS, with a maximum deviation not exceeding 2 dB. Our model exhibits significant improvement over TSM, particularly for HH polarization at higher wind speeds and incidence angles. However, further improvements can be made to our model by considering the effect of hydrodynamic modulation.