Backscattering models from one-dimensional sea surfaces

Recent asymptotic backscattering models are compared for one-dimensional multi-scale dielectric sea surfaces with Gaussian statistics and by considering the Elfouhaily et al. height spectrum (see J. Geophys. Res, vol.102, no.C7, p.781-96, 1997). We focus on the calculations of the normalized radar cross sections (NRCS) obtained from the weighted and local curvature approximations (WCA and LCA). recently published by T. Elfouhaily et al. (see Waves Random Media, vol.13. no.4, p.321-37, 2003), and from the first- and second-order small slope approximation (SSA(1) plus SSA(2) denoted as SSA), developed by A.G. Voronovich (see Waves Random Media, vol.4, no.3, p.337-67, 1994). In addition, Voronovich et al. (see Waves Random Media, vol.11, no.3, p.247-69, 2001) presented simulations of the SSA by making an assumption over the SSA(2) contribution (the model is referred to as SSAM). The NRCS computation is then similar to SSA(1), where the sea spectrum is substituted by a modified spectrum defined as the product of the sea spectrum by the second-order polarization term. The NRCS of the WCA, WCAQ (obtained from a quadratic approximation of WCA), LCA, SSA and SSAM backscattering models are compared for moderate wind speeds, for microwave frequencies and for backscattering angles ranging from 0° (nadir) to 70°.