南海北部内波活动下的声速剖面重构方法研究

Study on the Sound Velocity Profile Reconstruction Method under the Condition of Internal Waves in the Northern South China Sea

在内波条件下,水声信道稳定性变差,声速剖面的重构具有一定难度。与其他方法相比,经验正交分解法优点在于能用少量参数进行重构,而不需要引入大量的参数。利用南海北部陆坡测量的温度链数据,采用经验正交分解法对声速剖面进行重构。结果表明:在内波剧烈的南海北部海域,通过经验正交分解法重构声速剖面具有可行性,其前3个模态累计贡献率达到96.7%。分析样本的周期覆盖率对重构结果的影响后发现,当样本覆盖完整的海洋潮汐活动周期时,基于EOF分析对本组声速剖面的重构均方根误差小于1.1 m/s,重构声速剖面结果理想;而当采集的样本不能覆盖完整周期时,误差较大。

Under the condition of internal waves, the stability of underwater acoustic channel becomes weak,accompanied by the difficulty in the reconstruction of sound velocity profile. Compared with other methods, the advantage of the empirical orthogonal decomposition method is that it can be reconstructed with a small number of parameters, instead of using a number of parameters. In this paper, the empirical orthogonal decomposition method is used to reconstruct the velocity profile in the northern South China Sea. The results show that it is feasible to reconstruct the sound velocity profile in the northern South China Sea by the empirical orthogonal decomposition method, with the cumulative contribution rate of the first three modes reaching up to 96.7%. As a result of analyzing the sample coverage influence on the reconstruction, the EOF analysis of the reconstruction of sound velocity profile indicates that the RMS error is less than 1.1 m/s, when the sample covers the complete tidal cycle. The result of sound speed profile reconstruction is relatively ideal; however, if samples did not cover the full cycle, it would have lager error.