海洋潜涌（Obduction）是温跃层的水团通过有效夹卷涌升进入混合层的过程，是风生大洋环流的主要上升分支。潜涌水团与表层暖水混合，改变表层海水的性质，如海表面温度（SST）、盐度、叶绿素等，对气候和环境变化产生重要影响。目前，学界对热带印度洋的潜涌过程研究较少，限制了我们对该海区气候变化的认知和预报水平。热带印度洋区别于太平洋和大西洋的独特特征包括：1）受印度洋季风控制，混合层深度每年呈现两次极值；2）大气季节内振荡（ISO）活跃，导致海洋环流和混合层强烈的季节内变异。这两个特征使得该海区的温跃层通风过程与其它大洋显著不同，必须采用有针对性的方案进行研究。本项目聚焦热带印度洋的潜涌过程，针对其独特特征设计研究方案，揭示潜涌率在不同季节的空间分布、关键区域、年际变化及主要调控因子。重点探讨ISO对热带印度洋潜涌率的作用，理清ISO影响潜涌的主要物理机制，并讨论潜涌的变化对SST变异的影响。

Obduction, the process that water was irreversibly entrained from the pycnocline into the mixed layer, is the major vertical branch of wind-driven circulation. The mixing between obducted water and surface warm water will alter the properties of surface water, such as sea surface temperature (SST), salinity, chlorophyll and the nutrient abundance, which can greatly affect the climate and environmental variability. Now, there are a few studies about obduction in the tropical Indian Ocean (TIO), and the little knowledge will limit our understanding and prediction of climate change in the region. TIO is different from the Pacific and Atlantic Oceans: first, it is under the regime of monsoon, and the mixed layer depth features semiannual peaks in a monsoon cycle; second, it is one of the active region of atmospheric intraseasonal oscillation (ISO), which cause strong intraseasonal variability in oceanic circulation and mixed layer. These unique features make the ventilation in TIO much different from that in the other oceans. This project focus on the obduction in TIO. We will use a highly individualized approach to investigate the spatial-temporal distribution, key region, interannual variability and the regulating factor of obduction in winter and in summer, respectively. We will emphasize the contribution of ISO to obduction in the TIO and the underlying mechanism. Furthermore, we will also examine the impact of obduction variability on the SST.