摘要
In the Xiangshan Bay at the east coast of China,coastal marine pollution is conspicuous and severe in recent years.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 tidallyaveraged 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.
基金
The National Natural Science Foundation of China under contract No.41630966
the Youth Talent Support Program of the Laboratory for Marine Ecology and Environmental Science,Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.LMEES-YTSP-2018-02-03。