An Improved Two-Scale Model With Volume Scattering for the Dynamic Ocean Surface

Abstract

Abstract-The effects of the surface slopes joint probability density, the shadowing function, the skewness of sea waves and the curvature of the surface on the backscattering from the ocean surface are discussed and an improved two-scale model modified by these four aspects is used to calculate the backscattering coefficient of the dynamic ocean surface. In order to deal with the surface skewness driven by wind, a new complementary term derived from the small perturbation method is included in the improved model, in which the Fourier transform of the third-order cumulant function, surface bispectrum, is employed. On this basis, with the oceanic whitecap coverage taken into account, a composite model for predicting the ocean surface backscattering coefficient is constructed tentatively, which incorporates the volume scattering into the total one. Finally, with the vector radiative transfer (VRT) theory employed, numerical illustrations are carried out for the backscattering coefficients versus wind speed, incidence angle and azimuth angle, respectively. The predictions of the composite model are verified in K u -and K a -bands through the comparison of numerical results with many sets of measured data and the aircraft measurement experiment carried out in ZHOUSHAN sea area also supports this model.

Application of Clutter Suppression Methods to a Geostationary Weather Radar Concept

“…We assume that the mean motion of clutter is zero, with a velocity spread of 1 m/s due to random motions of the ocean surface and spacecraft. The ocean component is expected to dominate; if twoscale scattering theory (e.g., [6]) holds, the Doppler spectrum width should be determined by the wave orbital motions of the long wave spectrum. Measurements indicate that the ocean Doppler width should be less than about 1 m/s [7].…”

An Investigation on Numerical Characterization of Scattering From Target in a Dielectric Rough Soil Surface

“…As a whole, methods in studying the rough surface scattering can be categorized into two kinds: (a) the approximate, analytical methods; (b) the numerical methods. The approximate methods mainly include: the small-perturbation method (SPM) [1], the Kirchhoff or tangent plane approximation (KA) [2], the physical optics (PO) method, the two-scale method (TSM) [3], the phase perturbation method (PPM) [4], the small-slope approximation (SSA) [5], etc. The numerical methods mainly include: the method of moments (MOM) [6], finite difference time domain (FDTD) [7] method, finite element method (FEM) [8], method of multiple interactions (MOMI), Banded-Matrix-Iterative-Approach/Canonical Grid (BMIA/CAG) [9], forward-backward method (FBM) [10], fast multipole method (FMM) [11,12], curvilinear coordinate (C) method [13], etc.…”

A Four-Parameter M-Profile Model for the Evaporation Duct Estimation From Radar Clutter

“…We can see that the observed clutter has a very complex constructive/destructive interference. According to this interference pattern, the modeled clutter (note that the surface scattering theories are used in the modeling [23][24][25]) based on the four-parameter refractivity profile matches the observed clutter better than that based on the log linear profile. The clutter from the log linear M-profile very poorly matches the observed clutter power.…”