基于Lagrangian粒子追踪的渤海冬夏季环流及影响因素研究

基于三维非结构有限体积海洋模式（FVCOM）对渤海环流进行了数值模拟研究。数值模拟中采用三角形网格，可以更好地拟合渤海复杂的岸线边界。潮位、潮流、温盐模拟结果验证良好。通过对粒子的拉格朗日追踪研究了渤海冬夏季环流及潮、风、海气热交换和入海径流对渤海环流的影响。研究表明：粒子输移存在明显的三维结构；与渤海中部及海峡附近相比，三个湾内水体输送均较小、表底层相差不大；渤海夏季环流强度较冬季强；由风引起的拉格朗日水体输送对渤海环流影响较大；温盐环流对水体输送的影响主要在夏季，在冬季，影响可以忽略；河流只对河口附近环流结构有影响；夏季，与热盐、风相比潮流对拉格朗日水体输送贡献较小；在研究渤海的拉格朗日余流时，只考虑单分潮的作用将不能反映渤海的实际环流情况。

Study of Bohai Sea circulation and its influence factors during winter and summer based on Lagrangian particle tracing method

Numerical study of Bohai Sea circulation was conducted based on an unstructured grid, finite-volume, three-dimensional (3D) primitive equation ocean model. The model was easy to fit the irregular coastal boundary of the area of Bohai Sea with the use of the unstructured triangular grid. The simulated tides, tidal current and thermohaline field were well verified. Circulation of Bohai Sea during winter and summer and their relations between tides, wind, river discharge, and heat flux were studied by means of Lagrangian trajectory. It shows that the transport of particles behaved 3D structure in Bohai Sea. Compared with central Bohai Sea and Bohai strait, transportation in three bays and the differences between surface and bottom layer were small. Circulation in summer was stronger than it in winter. Wind played an important role in circulation, and thermohaline circulation was important during summer; however it was negligible during winter. River runoff only affected the area around river mouth. Compared with wind and thermohaline effect, the contribution of tides was small during summer. Circulation under only M2 tidal constituent could not reflect the actual circulation of Bohai Sea.