极小掠射角下分层海底的声反射损失研究

选取浅海大陆架的一种典型海底情况,建立了水-低声速沉积物-高声速海底半空间的分层海底模型。在极小掠射角的情况下,通过计算总的反射系数,并对反射系数的表达式进行变换,分析了分层海底的声反射损失。结果表明：反射系数的极点处出现了反射损失的突变,即在沉积层厚度与波长的比值为一系列特定值时,出现了高反射损失;同时反射损失在掠射角为1°时比掠射角为2°时要大,即掠射角越小,反射损失越大,进入海底的能量越多。

Study on acoustic reflection loss in layered seabed at very small grazing angle

A kind of typical seabed in the continental shelf of shallow sea is selected to establish a model of layered seabed which is composed of water-sediment with low acoustic velocity-half-space with high acoustic velocity.The acoustic reflection loss of layered seabed at very small grazing angle is analysed after calculating and transforming the gross reflection coefficient.A conclusion is drawn that a sudden high reflection loss shows at poles of reflection coefficient where the the sediment＇s depth-wavelength ratio equals a series of special values.Meanwhile,the reflection loss when the grazing angle is 1° is higher than the one when the grazing angle is 2°.That is to say the smaller the grazing angle is,the higher the reflection loss is and the more the energy into seabed is.