Olson Derek R, Jackson Darrell
Naval Postgraduate School, Monterey, California 93943, USA.
Applied Physics Laboratory, University of Washington, Seattle, Washington 98105, USA.
J Acoust Soc Am. 2020 Oct;148(4):2086. doi: 10.1121/10.0002164.
Acoustic scattering from layered seafloors exhibits dependence on both the mean geoacoustic layering, as well as the roughness properties of each layer. Several theoretical treatments of this environment exist, including the small roughness perturbation approximation, the Kirchhoff approximation, and three different versions of the small slope approximation. All of these models give different results for the scattering cross section and coherent reflection coefficient, and there is currently no way to distinguish which model is the most correct. In this work, an integral equation for scattering from a layered seafloor with rough interfaces is presented, and compared with small roughness perturbation method, and two of the small slope approximations. It is found that the most recent small slope approximation by Jackson and Olson [J. Acoust. Soc. Am. 147(1), 56-73 (2020)] is the most accurate when the root-mean-square (rms) roughness is large, and some models are in close agreement with each other when the rms roughness is small.
来自分层海底的声学散射既依赖于平均地球声学分层，也依赖于各层的粗糙度特性。针对这种环境存在几种理论处理方法，包括小粗糙度微扰近似、基尔霍夫近似以及小斜率近似的三种不同版本。所有这些模型对于散射截面和相干反射系数给出了不同的结果，并且目前没有办法区分哪种模型是最正确的。在这项工作中，提出了一个用于具有粗糙界面的分层海底散射的积分方程，并与小粗糙度微扰方法以及两种小斜率近似进行了比较。研究发现，当均方根（rms）粗糙度较大时，Jackson和Olson [《美国声学学会杂志》147(1), 56 - 73 (2020)] 提出的最新小斜率近似是最准确的，而当均方根粗糙度较小时，一些模型彼此之间非常吻合。
