摘要
The correlation of ambient noise with wind speed,and the depth dependence of ambient noise are both investigated,where the ocean noise data were recorded by a vertical line array in the northern South China Sea.It is shown that the correlation coefficients increase with increasing hydrophone depth during typhoon periods when the frequency≥250 Hz,which opposes the generally accepted knowledge that the correlation coefficients of noise level and wind speed decrease with increasing depth during non-typhoon periods.Particularly at frequencies of 250 Hz,315 Hz and 400 Hz,the correlation coefficients increase by more than 0.05 at depths ranging from 155 m to 875 m.At the three frequencies,the average noise levels also increase with increasing depth during typhoon periods.It is suggested that these differences are attributed to the wind-generated noise in shallow waters and the effect of"downslope enhancement"to sound propagation.During typhoon periods,the surf breaking and surf beat upon the shores and reefs are strengthened,and the source levels are increased.The wind-generated noise in shallow waters interacts with the downslope sea floor,with the noise-depth distribution changed by a"downslope enhancement"effect promoting noise propagation.
基金
The National Natural Science Foundation of China under contract No.41606116
the Natural Science Foundation of Fujian Province of China under contract No.2016J01019
the National Key R&D Program of China under contract No.2018YFC1405903。
