北极冰下声传播特性实验研究

Experimental study of under-ice acoustic propagation properties in the Arctic

通过2017年8月6日在北极海域开展的一次声传播实验,开展了冰下声传播特性实验研究。结合Burke-Twersky(BT)散射模型与射线模型,分析了冰下声传播的多途到达结构,研究了接收声强变化规律,解释了接收声强在30 min内衰减20 dB的现象,分析了接收信号的时间相关性,探讨了接收信号相关性较低的原因。实验结果表明,表面接收信号主要由小角度多次反转反射声线、一次海底反射声线和二次海底反射声线依次构成,表面声道到达信号显著强于海底反射信号。试验冰站在试验期间的运动导致了声传播信号强度和相关性的迅速衰减,并通过仿真得到了验证。

Under-ice acoustic propagation is studied based on the acoustic propagation experiment data acquired on the Arctic on 6th August 2017.Using Burke-Twersky(BT)model and ray theory,multipath arrival structure of under-ice sound propagation,the phenomenon of rapid attenuation of received sound intensity,and low temporal correlation coefficient are analyzed and explained.The experimental results show that the received signal is consist by small-angle multiple-reversals sound rays,sound rays with one bottom reflection and sound rays with twice bottom reflection.And the intensity of small-angle multiple-reversals sound rays is significantly greater than sound rays with bottom reflection.The movement of experimental ice station causes the rapid attenuation of sound propagation signal’s intensity and correlation during the experiment,and the maximum of the intensity attenuation can be as great as 20 dB.The conclusion above is verified by simulation.