In the Xiangshan Bay at the east coast of China, coastal marine pollution is conspicuous and severe in recentyears. As transport of the pollutants is closely related to the coastal circulation, there is a great practical significance to investigate the circulation in this area. In this work, the surface pattern and vertical profiles of Lagrangian residual velocity (LRV) were studied based on field observation data from the inner Xiangshan Bay. By tracking GPS-GPRS drifters' trajectories, the surface LRV pattern is going out in the central deep trough and flowing inwards near the shoreside. Combined with data from two mooring stations, vertical profiles of LRV is flowing out at surface and flowing in at the bottom, consistent with the gravitational circulation induced by baroclinic effects at the estuary. However, according to the diagnostic analysis, the main mechanism driving the residual current is barotropic rather than baroclinic. The LRV equation is controlled by the tidally-averaged barotropic pressure gradient force, tidal body force and tidally-averaged turbulent stress, while the tidally-averaged baroclinic pressure gradient force is one order of magnitude less than other forces. Additionally, the tidally mean eddy viscosity coefficient which is used in the expression of tidally-averaged turbulent stress might be not adequate and requires further studies.

Xiaoxuan Sheng;Qi Quan;Jinzhen Yu;Xinyan Mao;Wensheng Jiang

Key Laboratory of Physical Oceanography,Ministry of Education,Qingdao 266100,China;College of Oceanic and Atmospheric Sciences,Ocean University of China,Qingdao 266100,China;State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200241,China;Key Laboratory of Marine Environment and Ecology,Ocean University of China,Qingdao 266100,China

海洋学报（英文版）

[1]Xiaoxuan Sheng;Qi Quan;Jinzhen Yu;Xinyan Mao;Wensheng Jiang-.Tide-induced Lagrangian residual velocity and dynamic analysis based on field observations in the inner Xiangshan Bay, China)[J].海洋学报（英文版）,2022(10):32-40

recentyears,drifters,shoreside

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