浅海环境噪声时间平稳性与起伏特性实测分析

Analysis of Time Stationarity and Fluctuation of Measured Ocean Ambient Noise in Shallow Water

海洋环境噪声具有时域非平稳和幅度起伏的特性。对于浅海海洋环境噪声的时间平稳性与起伏特性的研究,能够揭示浅海海洋环境噪声在时间尺度上的特性,为岸基与浅海声呐的设计、使用以及近岸安保提供技术支持。本文对实测的浅海海洋环境噪声进行时间平稳性与起伏特性分析,通过计算瞬时功率谱起伏率的概率分布,选取适当判别门限来确定环境噪声的平稳时间,得到浅海环境噪声平稳时间在3~5min内,并且不同频率的平稳时间不同;浅海环境噪声低频段与高频段在不同时间尺度上的起伏特性不同。本文还讨论了海况、季节和实验地点对浅海环境噪声平稳性的影响,分析表明噪声源的变化是引起浅海环境噪声场平稳性变化的主要原因。

Ocean ambient noise is non-stationary on time, and fluctuating on amplitude. Studies on time stationarity and fluctuation of ocean ambient noise in shallow water can reveal characteristics of o- cean ambient noise in the time scale, and be helpful for the design and use of shore-based sonar and so- nar in shallow water, and coastal security. In this paper, the measured ocean ambient noise data in shal- low water are analyzed. Probability distribution of the rate of transient power spectrum fluctuation is calculated. Comparing the probability distribution with an appropriate threshold, stationary time about 3-5 minutes of ocean ambient noise in shallow water is determined, and fluctuation between low and high frequency band in different time scale is different. The impacts of the different sea conditions, different seasons and different experimental sites on the conclusions are also discussed. It is shown that a major factor affecting the stationarity of ocean ambient noise in shallow water is the changing of noise sources.