Three-Dimensional High-Resolution Numerical Study of the Tide and Circulation in the Pearl River Estuary and Its Adjacent Waters Part I:Model Building and Analysis

Based on an unstructured grid and finite-volume coastal ocean model(FVCOM),including highly accurate coastline and bathymetry data,a three-dimension model with high resolution is constructed in the Pearl River Estuary and its adjacent sea area to reproduce tides,tidal currents and residual currents.The comparison between observations and numerical modeling indicates that the computing results fit the measured values well.More elaborate co-tidal charts and pictures of tidal current ellipse of the four principal tide constituents as well as figures of tides,tidal currents and residual currents illustrate characteristics of tides and circulation in the research areas.The results show that there is mixed semidiurnal tide existing in the Pearl River,and the tide-type factor ranges from 1.1to 1.3.In the estuary,the tidal amplitude in the east side is higher than that in the west side,and the tide in the east propagates more quickly than that in the west;the tidal currents is mainly northwestern and southeastern with a rectilinear-current motion,and the maximum current velocity appears in the channel;the residual current in the channel flows towards the south,influenced by drainage of the runoff,while in the western shoal of the estuary,it flows towards the north,where a structure of circulation emerges.The tidal energy flux propagating from open sea,the maximum of which appears in the west and east channel of the estuary,mostly converges in the Pearl River Estuary,and circles counterclockwise around Qi'ao Island.