Research on experimentation and modeling of wind and rain generated ocean ambient noise

As wind and rain generated noise is an important part of ocean ambient noise, carrying out research on its regularities and characteristics is of great significance in both theory and potential military application. In this paper, the problem addressed is that of the ocean ambient noise field, which is to be thoroughly researched; and, the contribution of wind and rain, which is the main contribution to ocean ambient noise noise source in the frequencies from 1 k to 20 kHz. By simulation experimentation, data processing and analysis, it is established further research is needed on distributing characteristics of ocean ambient noise field in time, space and frequency. In this paper, experimental data of single raindrops and different rainfall strength in the wind-field is obtained (namely, in light rainfall, heavy rainfall, and extreme heavy rainfall). The methodology uses space average reverberation measure technique; direct acoustic wave near field noise measure technique equally; and, the characteristics of wind and rain-generated ocean ambient spectral noise is analyzed. A 3 parameters and a 5 parameters ocean wind and rain generated forecast empirical model are developed, based on the dissimilarity of the differences of noise producing mechanisms. These are then combined with ocean ambient noise forecast theory; and, single frequency acoustic inversion algorithm of rainfall. Acoustic inversion of the rainfall is also undertaken according to the single frequency rainfall experience model. The results show that the 3 parameters model is fit for a frequency lower than 25 kHz. The 5 parameters model has a high prediction precision within the frequency band of 10 k ~ 50 kHz in the case of the four discrete wind speed (0 ~ 4, 4 ~ 6, 6 ~ 8, 8 ~ 12 m/s) and rainfall more than 10 mm/h. The conclusion of this paper is significant for the further thorough research of the noise problem of the ocean ambient, and relativity researches of sea surface weather environment and ocean ambient noise.