象山港潮余流结构及水体半交换时间数值研究

基于三维FVCOM模型研究了象山港的潮流场特征，同时耦合Lagrange粒子追踪法及保守污染物输运模型，研究了湾内余环流结构、粒子长期迁移轨迹和湾内水交换特征等。结果表明:象山港海域为非正规的半日浅海潮，其中M2为其主要分潮；潮致余环流的特征明显，湾外分为两支，一支自牛鼻山水道东岸流入，绕六横岛经佛渡水道南部流出；第二支由佛渡水道进入湾内，并在口门内偏转再经牛鼻山水道西侧流出，其部分水体在牛鼻山水道中部与第一支汇合；西沪港以西峡湾内的余流基本指向湾口，西沪港内余流则指向口门；考虑湾内水体与湾外整体交换时，西沪港的污染物半交换时间在90 d左右，黄墩港和铁港内半交换时间在180 d左右，两支余流作用范围内的湾口半交换时间在20 d以内。

Numerical study of the tidal residual current structure and the water half-exchange time in Xiangshangang bay

Based on the three-dimensional FVCOM module, which is coupled with Lagrangian particle tracking model and conservative pollutant transport model, the hydrodynamic, the conservative pollutant transport, the tidal-induced residual current, the trajectories of characteristic particles and water half-exchange time were simulated. The results showed that tides in Xiangshan bay are irregular semidiurnal ones, of which M2 is dominant. The spatial pattern of tide residual currents was obvious, which could be divided into two branches. The first branch was flowing in from the east of Niubishan waterway, and then flowed out into the south of Fodu waterway bypassing Liuheng Island. The other was flowing in from the Fodu waterway, and flowed out from the east of Niubishan waterway, the part of which was joining in the first branch. The residual current in the west of Xilugang bay is pointing to the entrance of Xiangshangang bay, and the residual current in Xilugang bay is pointing to the harbor entrance. By considering the exchange of conservative pollutant in the whole Xiangshangang bay with the open sea, the water half-exchange time in Xilugang bay is 90 days, and which in Huangdungang and Tiegang bay is near 180 days, and the water half-exchange time in range of the branches is within 20 days.