基于FVCOM的廉州湾及周边海域三维潮汐潮流数值模拟

基于采用不规则三角网格和有限体积方法的FVCOM模式,建立廉州湾三维潮流数值模型来重现廉州湾及周边海域的潮位和潮流变化状况。根据模拟结果计算得到了较以往更为精细的廉州湾及周边海域K₁、O₁和M₂分潮的同潮图,并计算了由此3个分潮引起的潮汐不对称的变化情况。K₁和O₁分潮在廉州湾外主要以驻波的形式存在,进入廉州湾后转化为前进波;M₂分潮在廉州湾外主要以前进波的形式存在,进入廉州湾后前进波特征更为明显。K₁和O₁分潮流在廉州湾外以旋转流为主,在廉州湾内以往复流为主;M₂分潮流在整个研究海域以往复流为主。由潮余流场的分布特点可以看出自南向北由外海进入廉州湾的潮余流,在冠头岭处分为两支,一支逆时针转向西,另一支被冠头岭阻挡在其南侧形成顺时针封闭环流。在廉州湾内部同时存在2个环流系统,湾顶的气旋式环流和口门处的反气旋式环流。

Three-dimensional numerical simulation of tides and tidal currents in the Lianzhou Bay and adjacent areas on the basis of FVCOM

A 3-D high-resolution hydrodynamic model was established by using an unstructured grid, finite-volume coastal ocean model (FVCOM) to study the tides and tidal currents in the Lianzhou Bay and adjacent areas. The simulation results were in good agreement with in situ data. The co-tidal maps of K1, O1, and M2 indicated that K1 and O1 were mostly standing waves outside the Lianzhou Bay while M2 had a largely propagating character. However, all three constituents turned to propagating waves when going into the Lianzhou Bay due to the shallow waters. The tidal current ellipses were plotted to describe the characters of K1, O1, and M2 constituents. It was shown that K1 and O1 were rotating outside the bay but rectilinear along the water channels inside the bay; and M2 had a mostly rectilinear character over the whole area. The residual tidal current showed that the flow was divided into two branches by Guantouling Peninsula. One of them turned to flow westward, and the other was blocked at the south of the Peninsula to be a clockwise circulation. In the Lianzhou Bay, there were two circulation systems, the cyclonic one at the mouth of the bay and the anti-cyclonic one at the top.