Effects of typhoon "KAI-TAK" on deep ocean ambient noise in the South China Sea

By investigating the effects on deep ocean ambient noise of typhoon "KAI-TAK" which passed the north area of the South China Sea, it is shown that the wind speed, the rainfall intensity and the long wave swell caused by typhoon affect the ocean ambient noise significantly. The correlation between the ocean ambient noise and the wind speed during the typhoon is much better than that in the non-typhoon period in the same Beaufort scale. Analysis of the correlation between the 415 h ocean ambient noise measured data and wind speed shows that, when the frequency is greater than 300 Hz, the correlation coefficient between the ocean ambient noise and the wind speed is greater than 0.5. achieving a moderate correlation: when the frequency is greater than 630 Hz, the correlation coefficient is between 0.8 and 0.9, achieving a high degree of correlation. The correlation between the ocean ambient noise and the wind speed is better than that between the ocean ambient noise and the significant wave height when the frequency is greater than 300 Hz. The correlation between the ocean ambient noise and the wind speed in infrasonic band from 10 Hz to 20 Hz is poor in the South China Sea., because the shipping is busy in this sea area and the ocean ambient noise is contaminated by the ship noise even during the typhoon.