非线性随机表面Kirchhoff散射模式

A KIRCHHOFF SCATTERING MODEL FOR NONLINEAR RANDOM SURFACES

自从Longuet-Higgnins(1963)根据非线性作用导出较正态分布为准确的波面高度分布以来,高阶矩在军事、高科技等很多方面得到了应用。Huang等(1980)曾检验了高阶非线性分布,他们发现当波高概率分布中包含直至四阶项时与观测结果相符,但如果考虑更高阶不但效果不好,反而更差。尽管非线性随机过程在海浪理论中获得了广泛的应用。

According to two-dimensional nonlinear ocean wave model,the standard Kirchhoff surface scattering model is extended to include the forth order surface statistics. The bistatic radar scatterting coefficient,which includes the surface correlation function,the surface skewness function and the surface kurtosis function, is derived. The radar backscattering cross section is calculated and the effects of the surface skewness function and the surface kurtosis function are also discussed. Conclusions can be drawn as follows: (1) the effect of the surface correlation function is dominant for the radar backscattering cross section, (2)the effect of the surface skewness function is the largest at the direction of surface tilt,(3)the larger the incidence angle is,the larger the effect of the surface kurtosis function on the radar backscattering cross section.