菲律宾海的声速剖面结构特征及季节性变化

应用Argo资料研究了菲律宾海的声速剖面结构特征。通过统计分析选取了合理的跃层标准，分析了主跃层、季节性跃层和表面正梯度层的区域性分布及季节性变化。结果表明，菲律宾海主要受赤道流系和北太平洋西边界流系的支配，其环流结构和水团配置对声场结构影响很大；主跃层的经向差异显著，但季节性变化较小，其平均位置由南向北逐渐加深，强度逐渐减弱；季节性跃层的分布及变化主要受混合层的季节性变化以及北部海区冬季温跃层通风过程的影响，夏季较强较厚，冬季较弱较薄；深海声道轴季节性变化较小，南极中层水和北太平洋中层水的温盐差异是其经向分布差异的主要原因。综合考虑海区声速结构区域性和季节性特征，将其归纳为6种典型结构，得出了各类声速剖面的模态特征及垂直结构参数的统计特征值。

Distribution and seasonal variability of acoustic profile in the Philippine Sea

This study focuses on several aspects of the vertical structural characteristics of sound speed profiles (SSPs) in the Philippine Sea based on the Argo data. An improved criterion was selected to investigate the regional distribution and seasonal variability of main spring layer, seasonal spring layer, and near-surface positive-gradient layer. The results indicate that the Philippine Sea is dominated by the equatorial current system and western boundary currents, and the structure of the sound speed field there is significantly affected by the structure of currents and the distribution of water masses. The main spring layers change little seasonally; their depths grow deeper and the intensities become weaker form tropic to temperate zone. Influenced by the variety of mixed layers and ventilated thermocline in the northern region in winter, the seasonal spring layers are stronger and thicker (weaker and thinner) in summer (winter). The depths of the sound channel also vary little, the distribution of the Antarctic Intermediate Water and North Pacific Intermediate Water account for the meridional differences in the depth of the sound channel. In accordance with the structural characteristics, the SSPs in different regions and seasons are then divided into six types, and their statistical eigenvalues are obtained.