Effects of wind and rainfall on ambient noise in the East Indian Ocean

The wind speed and rainfall rate above the sea surface have significant effects on the ocean ambient noise, and the noise level can be predicted by using the ocean ambient noise model combined with wind speed and rainfall rate parameters. In this work, we study the ambient noise characteristics in the East Indian Ocean and analyze the influences of wind speed and rainfall rate on the ocean ambient noise. The results show that the correlation coefficient between high-band noise level and wind speed could reach 0.59 in the absence of rainfall, that the correlation coefficient between high-band noise level and rainfall rate can reach 0.85 in the presence of rainfall, and that the strong rainfall can increase the high-band ambient noise level by more than 6 dB. The wind-generated noise source level formula is also modified to make it applicable to the deep-sea environment of the East Indian Ocean, and the overall error between the model prediction of noise intensity level and the experimental noise intensity level in intense rainfall is within 2 dB after the modification. When the model is validated by using small-scale rainfall noise data, it is found that the noise source model using a non-uniform rainfall noise source at the sea surface during small-scale rainfall is more accurate than using a uniform rainfall noise source. The modified prediction model of wind-generated and rain-generated noise is important for predicting the ocean-ambient-noise characteristics in the Indian Ocean.