黄海暖流双核结构的数值模拟研究

The Yellow Sea Warm Current (YSWC) is the only seawater source of the Yellow Sea and the key pathway for the water exchange between the Yellow Sea and East China Sea. The formation and evolution of the YSWC play a critical role in the transport of heat, salinity, nutrients, plankton, and suspended sediment, and have significant impact on the distributions of temperature and salinity, the local biogeochemical cycle and the sediments distribution. Previous in situ observation and studies of the YSWC mainly focus on the both sides of the Yellow Sea Trough (YST) due to the baseline of the territorial seas. Consequently, the thermohaline and circulation structure in the YST in winter are still unclear and whether the YSWC has a double-core structure remains controversial. Base on the hydrological observations, satellite remote sensing data and high resolution numerical simulation results, this project plans to preliminary confirm the existence of the double-core structure of YSWC and depict its pathway. This project also plans to investigate the formation mechanisms and the annual variation of the double-core structure of YSWC.

黄海暖流是黄海唯一的外海水源，是控制黄海与东海水体交换的核心，其形成、消长变化直接影响热量、盐分、营养盐、浮游生物、泥沙悬浮物的输运，进而对黄海的温盐分布、生物地球化学循环、沉积物分布产生重要影响。受领海基线的限制，以往的调查观测及研究分析主要集中于黄海海槽两侧，对冬季黄海中部海槽区域的温度、盐度垂向结构尚不明确，黄海暖流是否存在双核结构仍存在争议。本项目拟基于历史水文观测资料、卫星遥感资料和高分辨率海洋数值模拟结果，通过统计分析和理论诊断，并结合数值试验，对黄海暖流的三维结构进行深入系统的研究。希望通过本项课题研究，能初步证实黄海暖流存在双核结构，并对其路径进行刻画，阐明黄海暖流双核结构形成的动力机制，初步探讨黄海暖流双核结构的年际变化。

历史观测资料和数值模拟结果都证实冬季黄海海槽底部存在西北向蛇形流动的黄海暖流底部分支，数值试验证明北风是驱动形成黄海暖流底部分支的动力机制，北风的强弱决定了黄海暖流底部分支的强弱。底部分支在北上过程中流经数个深坑，受位涡守恒约束，其路径呈现蛇形弯曲，并逐渐西偏。同时数值试验还发现，底摩擦非常小时，黄海暖流底部分支消失，只存在西侧分支，随着底摩擦增大西侧分支变弱，而底部分支则变强。黄海暖流底部分支可能会对黄海的温盐分布、生物地球化学循环、沉积物分布产生重要影响。