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海洋的声速结构对水下声传播有重要影响,在印度洋中北部复杂多变的海洋物理和水文环境中,获取声速剖面的时空统计分布规律对水下目标探测和水下声通信有重要意义.由于垂直梯度法在声速结构分析中的局限性及其在印度洋中北部海域的适用性问题,采用多元统计分析中的最优分割法对声速跃层进行分析,并应用最近10年的地转海洋学实时观测阵数据对印度洋中北部海域声速剖面的特征量进行了计算,获得了声速跃层的垂直结构特征和时空变化规律;还利用经验正交函数(EOF)表示方法,分析了印度洋中北部声速剖面拟合精度随EOF阶次的分布特点.根据印度洋的海洋物理特征,揭示了声速剖面特征量时空演变的内在物理机理.研究结果表明:最优分割法是适合印度洋声速结构的跃层判断方法,并提出了相应的判断准则参数;声速剖面拟合精度随EOF阶次变化的区域性分布特征较明显,其季节性变化较小;印度洋中北部的深海声道轴只在5°S以南明显存在,在15°S—25°S附近海域存在三个跃层;印度洋中北部声速剖面结构可分为单跃层、双跃层Ⅰ型、双跃层Ⅱ型和三跃层四种类型以及春夏秋冬四个季节模态.声速剖面的分析结果对于水声传播和声纳系统的使用具有一定参考意义.
The sound velocity structure of the ocean has an important influence on underwater acoustic propagation. In the complex and varied marine physical and hydrological environment in the central and northern Indian Ocean, obtaining the statistical distribution of space velocity in the sound velocity profile is of great significance for underwater target detection and underwater acoustic communication. Due to the limitation of the vertical gradient method in the structure analysis of sound velocity and its applicability in the central and northern Indian Ocean, the method of optimal segmentation in multivariate statistical analysis is used to analyze the acoustic velocity thermocline, The real-time observation array data are used to calculate the characteristics of the sound velocity profile in the central and northern Indian Ocean. The vertical structure and the temporal variation of the acoustic velocity layer are obtained. The empirical orthogonal function (EOF) method is also used to analyze the characteristics of the mid-northern Indian Ocean According to the marine physical characteristics of the Indian Ocean, the intrinsic physical mechanism of the spatiotemporal evolution of sonic velocity profile features is revealed. The results show that the optimal segmentation method is suitable for the thermocline judgment of Indian Ocean sound velocity structure Method, and put forward the corresponding judgment criterion parameters; the fitting accuracy of sound velocity profile changes with the region of EOF order Climatic features are obvious and their seasonal variation is relatively small. The deep-sea channel axis in the central and northern Indian Ocean is only evident in the south of 5 ° S, and there are three layers in the sea near 15 ° S-25 ° S. The sound velocity in the central and northern Indian Ocean The cross-sectional structure can be divided into four types of single-jump, double-jump type Ⅰ, double-jump type Ⅱ and triple-jump and four seasons of spring, summer, autumn and winter.The results of sound velocity profile for acoustic propagation and sonar system The use of a certain reference value.