深海表面层声速剖面变化对声传播的影响

在我国部分海域，表面声速常常在较短的时间内从弱正梯度变为弱负梯度，这将对表面附近的声传播产生巨大影响。本文通过数值模拟的方法，讨论了表面层声速梯度变化对声传播的影响，同时解释了某次海上实验出现的异常现象：在同一地点同一航向，前后两天海况相同，水文相差不大，第一天的实验可以在50km之外接收到信号，而第二天只能在30km处才能收到信号。

The effect of variation in sound velocity profile near the ocean surface on sound propagation in deep sea

In deep ocean, the profile of sound velocity near the ocean surface often turns from weak positive gradient to weak negative gradient in a short time, this may exert an enormous influence on the acoustic propagation near the surface. This article discusses the impact on acoustic propagation in deep sea due to sound velocity profile variations near the ocean surface and explains an unusual phenomenon that observed during an experiment: on the first day one can receive signal outside 50km, but on the next day, for the same place, course, state of the sea, and only a little difference of the velocity profile, one can only receive signal within 30km.