西太暖池区中深层跨等密面混合的时空变化特征及其影响机制

Intermediate- and deep-water turbulent diapycnal mixing (hereinafter referred to as diapycnal mixing) in the western Pacific Warm Pool is important to the global meridional overturning circulation. Study on the spatial and temporal variation of diapycnal mixing is important for understanding exchange processes of substance and energy in the ocean. Turbulent dissipation rate or eddy diffusivity is estimated with three methods: inertial dissipation method, fluctuating velocity shear method and finescale parameterization method. The first method utilizes high frequency velocity obtained from moored ADV (acoustic Doppler velocimeter), the second one utilizes velocity shear microstructure data, and the third one utilizes finescale stain or shear variance obtained from Argo (array for real-time geostrophic oceanography) and shipboard and moored CTD (conductivity-temperature-depth) and ADCP (acoustic Doppler current profiler). We analyze the estimated values of turbulent parameters with objectives 1) to present the temporal variation and spatial structure of diapycnal mixing; 2) to illustrate the linkages between diapycnal mixing and its potential influencing factors including various bathymetry types and features, bottom roughness length, tide, mean current, intermediate and deep ocean jets, topographically-trapped wave, wind and eddy; and 3) to reveal the main physical processes that control the temporal variations at different time scales and the main influencing factors that control the spatial structure.

西太暖池区中深层跨等密面混合是经向翻转环流的重要影响因素，其时空变化特征对认识西太暖池乃至全球的物质能量交换过程至关重要。本项目综合使用惯性耗散法分析锚系高频流速数据、脉动流速剪切法分析微尺度数据和细尺度参数化法分析Argo、船、锚系测得的温盐流速数据来估算湍动能耗散率或垂直湍扩散系数，获得西太暖池区中深层跨等密面混合不同尺度的时间变化特征和空间分布特征，研究地形类型和特征、地形粗糙度、潮流、上层平均流、中深层射流、地形陷波、风应力和中尺度涡等可能因素对时空变化特征的影响机制、范围和差异，揭示影响西太暖池区中深层跨等密面混合不同尺度时间变化的主要物理过程和影响空间特征的主要因素。

西太暖池区中深层跨等密面混合是经向翻转环流的核心影响因素，其时空变化特征对认识西太暖池乃至全球的物质能量交换过程至关重要。本项目于2015和2016年参加了2次西太平洋综合考察航次，获得了西太平洋代表性海域15个站位的全水深湍流剖面和16个站位中深层温盐环流的连续2年观测资料，基于此研究了西太平洋中深层环流基本结构和特征，分析了中深层湍流混合的特征和影响机制。项目现已发表3篇高水平SCI论文。