渤海主要分潮的模拟及地形演变对潮波影响的数值研究

NUMERICAL STUDY ON TIDES OF BOHAI SEA AND IMPACT OF TOPOGRAPHY CHANGES ON THE TIDAL WAVE SYSTEM

基于FVCOM数值模式,利用1972年和2002年水深岸线数据,分别对渤海主要潮波系统进行模拟,研究了水深岸线变化对渤海主要分潮的影响。结果表明渤海地形演变会引起各分潮无潮点位置移动和振幅的改变,其中M2、S2分潮黄河口附近无潮点位置向东北方向迁移20km以上,且渤海湾湾顶振幅减弱,莱州湾内振幅增强;K1、O1分潮位于渤海海峡附近的无潮点亦向东北方向偏移,移动距离为10km左右,且渤海湾湾顶振幅明显减弱。在此基础上,本文通过敏感性数值实验,对导致黄河口外M2分潮无潮点位置移动的主要因素进行了初步分析。结果显示,在岸线不变的情况下,水深变化导致无潮点向东北方向迁移;而岸线变化导致无潮点向东南方向迁移。

Tides in the Bohai Sea are sensitive to the water depth and coastline. In this paper, two numerical experiments were set up based on FVCOM, to study their impacts on the major tidal constituents in the Bohai Sea using different topography and coastline data(1972, 2002). The evolution of topography causes the amphidromic point a northeastward displacement and the amplitude changing. For M2 and S2 tidal constituents, the locations of the amphidromic points near the Huanghe(Yellow) River estuary move about 20 km northeastward; meanwhile, the amplitudes decrease in the Bohai Bay and increase in the Laizhou Bay. For K1 and O1 tidal constituents, the amphidromic points move about 10 km northeastward and the amplitudes decrease significantly in the northern Bohai Bay. The numerical sensitivity experiments show that the amphidromic point of the M2 constituent near the Huanghe River estuary would move northeastward if considering the depth evolution only, and would move southeastward if taking account of the coastline evolution only.