南海北部涡致跨陆坡输运的季节和季节内变化

Mesoscale eddies occur frequently in the northern South China Sea (SCS). After formation, most of the eddies move to the southwest along the continental slope, which consequently facilitates the dynamic exchange between shelf and deep ocean in terms of water mass, material, and energy. So far, a lot of progress have been made to understand the upper ocean circulation in the northern SCS. However, the dynamics and controlling factors of cross-slope exchange still remain largely unknown, especially for contributions from mesoscale eddies due to lack of observations that can efficiently capture transient eddies. In this study, we will combine multiple data sources from in-situ measurements and satellite altimeter data with a high-resolution numerical model to examine characteristics and dynamics of eddy induced cross-slope exchange in the northern SCS by conducting numerical sensitivity studies and budget balance diagnosis. We will focus on the variability of eddy-induced transports and their three-dimensional structures at seasonal and intra-seasonal timescales. With this study, we would reveal the statistical properties of mesoscale eddies in the northern SCS and quantify contributions of cross-slope exchange from eddies, which will advance our.understanding on the dynamic nature of upper ocean circulation in the northern SCS.

南海北部涡旋频发，多数涡旋生成后沿着陆坡向西南方向传播，对南海北部陆架与深海之间在物质和能量方面的交换产生了至关重要的影响。目前，针对南海北部上层环流的研究很多，但对跨陆坡输运的研究还不系统，特别是由于观测数据的相对缺乏，人们对中尺度涡旋在跨陆坡输运贡献方面的研究非常少，潜在的动力机制和控制因子还不明确。本项目在此背景下开展，拟综合现场观测的温盐和流场、卫星高度计数据等资料，结合高分辨三维区域模式并设计敏感性试验与动力诊断分析，研究南海北部涡致跨陆坡输运的规律和动力机制，重点关注其季节和季节内的变异。将采用统计分析的方式揭示南海北部涡旋的基本特征，阐明南海北部涡致跨陆坡输运的三维结构以及变化规律，量化中尺度涡旋对跨陆坡热盐输送的贡献和对局地流场的影响。本项目的开展将促进对南海北部环流动力过程的认识。

在季风、黑潮、涡旋等因子作用之下，南海北部环流过程复杂，存在显著的多尺度变化，然而现有研究对其变化规律和动力机制的认识尚不全面。基于此，本项目综合现场观测数据、卫星遥感数据等资料，结合数值模式并设计敏感性试验与动力诊断分析，对南海北部环流的多尺度变化（涡旋影响和年际变化）开展了研究。项目构建了一个覆盖南海北部陆架的高分辨率数值模式，并进行了年际尺度模拟，获得了一套具有年际尺度的三维模式输出数据集；结合观测数据和数值模式结果，解析了南海北部陆架和陆坡流的年际变化规律和驱动机制；利用三种涡旋追踪方法，明确了南海中尺度涡旋的时空分布特征；揭示了南海北部中尺度涡旋引发的跨陆坡输运对南海深水海盆的动力和生态环境的影响；在本项目的支持下发表了SCI论文10篇，合作培养博士研究生2名。