The ocean ambient noise is one of the important parameters in sonar equation. The ocean ambient noise includes diverse and complex sources like waves, marine life, ships, and etc. Using different ways to analyze are needed to understand the complicated properties of ambient noise. Empirical equation obtained from linear regression of wind speed and ambient noise data is a common method to predict noise level. In this article, the ambient noise data were collected from experiments at northeastern sea of Taiwan in 2007, 2008 and 2009. Applying corresponding wind speed data to observed noise level the time series, coefficient of determination is used to estimate how noise fit with wind speed data of regression. The K-S test and Sea States are used to determine the wind speed threshold. Although it is the same sea area in three years, the ocean ambient noise still has variations due to time and variance of sound sources, so it is important to be investigated. This study compares the statistical properties and distribution in ambient noise level and frequencies with corresponding wind speed in same season.

Ocean Ambient Noise covers wide range except target signal in the sonar equation and is an influential parameter in sonar performance. Empirical equation obtained from linear regression of wind speed and ambient noise data is a common method to predict the noise level. Both ambient noise and wind speed data collected from experiments in southwest and northeast Taiwan sea were analyzed in statistics and time series. Experiment data was also used for prediction equations and further analysis. Coefficient of determination (r2) and F-test for the slope of the regression line were used to estimate how noise fit with wind speed data and the credibility of the regression. The result of the analysis was that the distribution of r2 changes with regions. The values of r2 calculated from northeast experiment data are higher than southwest because of the high percentage of high wind speed. The data from the northeast experiment is considered more appropriate for the prediction of noise level because the higher value of r2. All results of F-test showed the correlation between wind speed are statistically significant except the winter data in the southwest experiment. By using these two indicators, the credibility of the prediction equation can be realized and the prediction performance of sonar is promoted.