【作者】 耿姗姗；

【导师】 王坚红；

【作者基本信息】 南京信息工程大学 ， 气象学， 2011， 硕士

【摘要】 本文基于FVCOM海洋模式,采用无结构、分辨率可变的不规则三角网格及有限体积法,考虑天文潮、径流及台风等作用的影响,建立了包括长江口、杭州湾在内的近海风暴潮数值模型。建立了长江口、杭州湾海域三维潮汐潮流水动力模型,与实测资料对比并讨论研究海域的潮汐潮流性质,验证结果表明本文所建立的水动力模型能够准确再现长江口、杭州湾水动力特性,这为下文风暴潮的模拟奠定了水动力基础。通过建立四组理想风场试验,讨论了FVCOM模拟的理想风生流分布情况。统计分析自1995年以来22个对长江口、杭州湾影响较为显著的台风,并归纳出直接入侵长江口、杭州湾的两类台风：Ⅰ类为正面登陆型,Ⅱ类为沿海北上型。对台风的风、压场分别采用了WRF模式与台风模型进行模拟,本文中台风模型的气压场计算采用Takahashi和Fujita T.公式,风场采用Ueno Takeo公式。经与实测资料对比后发现,台风模型可以满足FVCOM风暴潮对风、压场的要求,且调试方便,因此采用台风模型结果作为风暴潮的气象强迫。基于TC9806及TC0012台风,建立了两类影响长江口、杭州湾的典型风暴潮FVCOM数值模式,并分别建立了天文潮、台风及二者耦合作用下的三组数值试验进行对比分析。结果表明影响单站增、减水的因素除与台风强度有关,还与台风移动的路径有关。表层海流对台风的响应最为显著,且表层流速增幅大于底层；风暴潮过程中单点海流流向仍呈现周期性变化,仅在台风到达时流向出现改变,体现了长江口、杭州湾海域天文潮的主导作用；台风与地形的联合作用使得海流在局地小范围出现环流。台风过程同时造成了海流动量下传,深度直达海底。欧拉余水位受台风强迫,在近岸出现显著变化,余水位增幅可高达近1m。表层余流在台风前方的强风势与海岸地形的共同作用下形成急流,流速可达1-1.5m/s。垂直方向上余流最大梯度出现在岸界与地形共同作用的深度为5-6m的浅水区。更多还原

【Abstract】 A numerical model for coastal storm surge simulation has been established to cover the Changjiang estuary and Hangzhou Bay based on the Finite Volume Coast and Ocean Model (FVCOM). FVCOM adopts an unstructured, variable resolution triangular grid and finite volume method. In the same time, the model takes the effects of astronomical tides, surface runoff and typhoons into account.A 3-D numerical tidal model for the Changjiang estuary and Hangzhou Bay is established at first, and the characteristics of the tide and tidal current have been discussed. The computed results agree with the observation well. The tidal model also laid the groundwork for storm surge simulation.Four numerical experiments model for FVCOM ideal wind simulation have been established to test the simulated wind currents.22 typhoons in the Changjiang estuary and Hangzhou Bay are statistically analyzed, and two types of typhoons which invaded directly into Changjiang estuary and Hangzhou Bay are generalized:I is landed on Zhejiang province, II is moved northward on the sea. The WRF model and typhoon model are used to simulate the wind and pressure of the typhoon. The pressure field of typhoon model is computed by used of Takahashi and Fujita T., and the wind field is by Ueno.After comparing with the observed data, the typhoon model meets the storm surge model’s requirements, and it’s easy to adjust. So the study adopts the result of the typhoon model as meteorological field of the storm surge.A storm surge model for the Changjiang estuary and Hangzhou Bay is established considering separately the influence of astronomical tidal, typhoon (TC9806 and TC0012) and their coupling. The set-up and set-down of local water level are impacted by the intensity and the path of the typhoon. The variety of single point of the surface sea current under the three conditions is more obvious than the bottom one; the single point of flow direction under storm takes on the periodic variation still, and the difference happened only when typhoon arrives, it shows the important effect of the astronomical tidal in the Changjiang estuary and Hangzhou Bay; the distribution of the sea surface current is influenced by the intensity and path of the typhoon, and some small circulations appear at local small area under the typhoon and topography’s combined action. The oceanic momentum which caused by typhoon transferring downwards can get to the bottom of the sea. The coastal residual water elevation was influenced remarkablely by typhoons, and the effect of storm surge can make a set-up nearly 1m. The surface residual currents generate the jet which mainly repose to the strong wind of typhoon and the jet speed could get 1-1.5m/s. The biggest gradient of residual current in vertical section happens at shallow waters about 5-6m in deep.更多还原