Investigation of electromagnetic backscattering from nearshore sea surfaces modulated by shoaling effect

摘要

The electromagnetic (EM) scattering features of radar scattered echoes from nearshore sea surfaces are investigated using the second-order small-slope approximation (SSA-Ⅱ). The joint influences of wind fetch and water depth on the normalized radar cross section (NRCS) of and Doppler spectra for echoes from nearshore sea surfaces are mainly studied. The numerical results show that with a further increasing fetch, the excess of NRCS for small depth sea over that for deeper sea increases, and Doppler spectral features are also intensely influenced by nonlinear interactions between waves in the large wind fetch and small water depth marine environment. These both indicate that the effects of the finite depth are more prominent with increasing wind fetch, especially for HH polarization.