高度-斜率相关对随机界面背向散射脉冲传播时间统计特性的影响

Fuks和Godin关于随机界面背向散射脉冲传播时间统计特性理论只适应于随机界面和波阵面“up-crossing”且界面高度-斜率不相关情形。文中扩展以上分析,考虑随机界面和波阵面“up-crossing”和“down-crossing”2种不同的相交情况,给出确定最早返回的2个脉冲传播时间概率的一般公式;并研究界面高度与斜率之间存在相关性的一般情形。数值结果表明:第1个和第2个返回脉冲传播时间的概率分布跟界面高度-斜率相关系数的绝对值有关;传播时间是相关系数绝对值的增函数。

Effect of the Elevation-Slope Correlation on Travel-Time Statistics of Backscattered Pulses from a Random Rough Surface

The theory of Fuks and Godin [Waves Random Media,14, 539-562(2004)] on the travel-time statistics of backscattered short pulses from a random rough surface is only applicable to cases of "up-crossing" and where the surface elevation-slope is uncorrelated.In this paper,we not only consider the difference between "up-crossing"and "down-crossing" of the wavefront and the stochastic surface and present the general equations of the probabilities of the travel time of the earlier arrivals,but also extend the results above to the case in which surface elevation and slope are correlated.The numerical results show that the probability distribution functions of the travel times of the first and second pulses are determined by the absolute value of the elevation-slope correlation coefficient;the first and second travel times are all increasing functions of the absolute value of the correlation coefficient.