【作者】 谭凤；

【导师】 张庆河；

【作者基本信息】 天津大学 ， 水利工程， 2012， 硕士

【摘要】 准确获取极端天气条件下近岸海域的波浪要素是保障港口与海岸工程设计安全的前提条件,因此研究台风、温带气旋和寒潮等大风过程中波浪的生成与演化具有重要意义。近年来,海浪数值模拟已成为研究近岸波浪的重要手段,而风场数据的合理性直接影响着波浪模拟结果的合理性。另外,近岸海域波浪模拟还需要考虑潮流的影响。为此,本文采用中尺度大气模式WRF来模拟风场以获取高精度风场数据,采用FVCOM二维潮流模式模拟近岸流场,采用SWAN海浪模式模拟波浪场,建立了大气-海洋-海浪模型系统,对台风及温带风暴过程中的近岸波浪进行模拟。论文的主要研究内容和结论如下:1、通过对比分析,合理确定了台风及温带风暴风况下WRF模式的各种参数,并对两种风况下大气数据同化的效果进行了分析。结果表明数据同化对台风的结果影响较大,对温带风暴过程的结果影响较小。为了使数据同化的效果更明显,需要更多的实测数据来进行同化。2、将WRF模型计算数据与QSCAT/NCEP混合风场数据及QSCAT/NCEP与台风模型合成风场数据进行了比较,结果表明WRF模型的计算结果明显优于其它两种风场数据,WRF模型计算值较其它数据更接近实测数据,可以比较合理地描述台风和温带风暴大风过程的风速、风向,可为近岸波浪场的模拟提供高精度风速。3、利用FVCOM二维潮流模式和SWAN海浪模式模拟2007年韦帕台风及2007年3月温带风暴潮流和波浪过程,将模拟结果与实测值进行对比验证,结果表明数值模型能很好地模拟台风和温带风暴过程的潮流和波浪。4、对台风风场作用下波浪变化规律进行了分析,结果表明在台风旋转风场的作用下波浪的传播方向会发生改变,波向逐渐变为与台风风向一致,并形成旋转的波浪场,但波浪场漩涡的位置相对风场漩涡的位置存在一定的滞后性。5、对浅水区域潮流对波浪的影响进行了分析,结果验证了近岸区域潮流对波浪作用的显著性,在近岸波浪计算时需要考虑潮流的作用。更多还原

【Abstract】 Accurate nearshore wave data in extreme weather is a prerequisite for design safety of port and coastal engineering. It is of great significance to investigate the wave generation and propagation during strong wind processes of typhoon, extratropical storm and cold wave. In recent years, the numerical simulation of waves has become a very important method for sea wave research. However, the reasonability of wave results directly depends on the reasonability of wind data. In addition, the effects of current should be taken into accout in nearshore wave simulation. Therefore, an atmosphere-ocean-wave system was developed to simulate the typhoon and extratropical storm wave process based on the mesoscale atmospheric model of WRF, the two-dimensional tidal current model of FVCOM and the wave model of SWAN. The main contents and results are as follows.(1) Various parameters of WRF under strong wind actions of typhoon and extratropical storm were determined by comparative analysis. The effects of data assimilation under two wind conditions were analyzed. It was indicated that data assimilation had great influence on typhoon wind results while having little influence on extratropical storm wind results. More observation data should be considered to improve data assimilation effects.(2) Comparisons among winds from WRF, QSCAT/NCEP Blended Ocean Winds, and mixed winds of QSCAT/NCEP and typhoon model showed that the WRF simulation data agree with the observation data more satisfactorily than the other data. WRF model can well simulate the wind speeds and directions in typhoon and extratropical storm and can provide high-precision wind data for wave simulation.(3) The two-dimensional tidal current model of FVCOM and SWAN wave model were applied to simulate the current and wave processes for the WIPHA typhoon in 2007 and the extratropical storm occurred in March, 2007. It is shown that the numerical models could well simulate the current and wave process of WIPHA typhoon and the extratropical storm.(4) The analysis of wave propagation under typhoon wind conditions indicated that the wave direction varied and was gradually consistent with wind direction with a circular wave field, but the center of wave field had a time delay compared to typhoon wind center.(5) The effects of tidal current on wave in shallow water were analyzed. It is verified that the tidal current had a remarkable effect on wave height in shallow water of nearshore zone. It is suggested that the effects of tidal current should not be neglected in nearshore wave simulation.更多还原