IOCAS-IR  > 海洋环流与波动重点实验室
典型海湾风暴潮的非线性与共振效应及其危险性评估研究
杨万康
Subtype博士
Thesis Advisor尹宝树
2019-05-13
Degree Grantor中国科学院大学
Place of Conferral中科院海洋所
Degree Name理学博士
Degree Discipline物理海洋学
Keyword风暴潮,非线性效应,共振,围垦工程,可能最大风暴潮水位
Abstract

我国遭受风暴潮灾害最严重的地区主要集中在华南沿海和东南沿海,尤其是在沿岸海湾内建设了大量的海洋工程,这些工程改变了海湾的自然形态和水动力环境,一旦发生重大海洋灾害,后果将十分严重。因此开展沿海典型海湾内的风暴潮机理研究及危险性评估,对于提高海湾地区的防灾抗灾能力具有重要意义。本文选取广西铁山湾和浙江三门湾作为研究对象,主要研究内容及结论如下:

首先基于ADCIRC二维数学模型对 1409威马逊台风经过铁山湾期间的天文潮-风暴潮非线性效应进行了研究,结果表明:铁山湾内天文潮和风暴潮的非线性作用较强,只考虑纯气象驱动会对预报结果造成较大误差,由天文潮与风暴潮相互作用产生的非线性水位在湾顶处达到最大。通过理论公式推导,建立了非线性水位和各影响因子之间的直接关系式。影响天文潮-风暴潮非线性效应的主要因子为风应力和底摩擦力的合力项、非线性对流项,两者对非线性效应的影响随空间和时间的变化而变化。当风暴潮峰值水位叠加不同相位天文潮时,非线性水位在高潮位达到负值最大,在落潮时达到正值最大,而且海湾内非线性作用越强,总水位峰值相对于天文潮高潮位的延迟时间就越长。

其次对三门湾历史上的强风暴潮增水过程进行经验模态分解后发现三门湾风暴潮增水过程中存在共振现象。然后采用理论公式推导和边值法对共振周期及振幅变化进行了研究。结果表明三门湾内各水道共振特征有所差异,共振周期总模态不超过5个,共振周期第一模态对应的水位振幅最大,然后依次递减,共振水位振幅在湾顶处达到最大。

三门湾内大量建设的围垦工程使得自然岸线和水深地形都发生了改变,利用数值模型对工程实施后的潮汐和风暴潮水位变化进行了预测研究。结果表明围垦工程使得海湾内的天文潮振幅有所下降,地形淤积导致的潮汐振幅减小幅度要远大于岸线改变产生的影响。对风暴潮水位的影响随台风路径的不同而有所差异,地形改变是影响三门湾内风暴潮峰值水位变化的主要因素。西北向台风路径下峰值水位抬升最明显,水位增加显著区域主要集中在健跳水道及三门湾湾顶处,峰值水位抬升最大可达0.4m

 

最后基于数值模型以可能最大热带气旋参数为基础构建了多种假想台风路径计算了三门湾内的可能最大风暴潮水位(PMSS),结果表明沿西北向且距离三门湾中心为最大风速半径处登陆的台风使得风暴潮增水达到最大,当PMSS叠加天文高潮位时,水位已经超过了沿岸海堤高程。将三门湾沿岸陆地依照高程概化为计算区域进行漫堤计算,淹没最严重的区域出现在湾顶处,最大淹没面积达到了120 km2,三门核电厂址前沿水位与不溢流相比下降了0.5m。本研究可为三门湾沿岸围垦工程及核电厂址的安全防护提供科学依据。

Other Abstract

The storm surge causes great damage to Southeast and South China every year. Especially, many reclamation projects have been initiated and resulted in coastline change and hydrodynamic conditions change. The loss would be severe once marine disasters occur. Therefore, it is critical to study the mechanism and risk assessment of storm surge in typical bays to improve storm surge disaster prevention. Tieshan Bay in Guangxi and Sanmen Bay in Zhejiang are selected as research objects in this paper. The main research contents and conclusions are as follows:

Firstly, a two-dimensional ADCIRC model has been presented in which the storm surge in Tieshan Bay induced by Typhoon Rammasun of July 2014 to investigate tide-surge interaction. The result shows that nonlinear effect is strong in Tieshan Bay and leads to large error in storm surge simulation when only meteorological force considered. Nonlinear levels due to tide-surge interaction increase from outside the bay to inside. Through the derivation of theoretical formula, a direct relationship between the nonlinear residual levels and the dynamic influencing factors is established. It is demonstrated that the combination of wind stress and bottom friction terms and advection terms play leading roles in the derivations. The combination of wind stress and bottom friction terms and advection terms show complex spatial and temporal variation. Numerical experiments are conducted to study the surge peak superimposed with different phase of tidal levels. The nonlinear level reaches maximum negative value at high tide and maximum positive value at falling tide. Moreover, the lag time of maximum total level relative to the high tide gets longer where the nonlinear effect is stronger.

Secondly, Empirical Mode Decomposition method (EMD) is applied to decompose storm surge data in Sanmen Bay and presence of resonance is found. Then the resonance phenomenon is studied by theoretical formula derivation and numerical simulation. The numerical model results show that there are less than five resonant period modes in the Sanmen Bay and resonance characteristics of the waterways in Sanmen bay are different. The amplitude of first mode of the resonant period is largest and decreases in sequence. The resonant amplitude gain gradually increases from outside of the bay to inside, especially significant at the top of bay.

Reclamation projects in Sanmen Bay have changed the natural shoreline and topography. A two-dimensional numerical model is applied to evaluate the impacts of reclamation projects on tidal and storm surge levels in Sanmen Bay. The model result shows that the tidal level decreases due to reclamation projects and bathymetry change has a more significant impact on tidal amplitude than shoreline change effect. The variation of surge level in different types of typhoon paths is complex. Similarly, the rise of peak surge levels due to the change of topography is also significant. The maximum surge level rise occurs in the path of northwest landing typhoons and exceeds 0.4m at the top of the bay.

At last, a storm surge model for Sanmen Bay is established and a number of hypothetical typhoon paths using possible maximum tropical cyclone parameters are applied to calculate the possible maximum storm surge at Sanmen Bay. The model results show that the north-west landfalling path to the left of bay by maximum wind radius causes the maximum storm surge in Sanmen Bay. Strom surge inundation happens when the PMSS superposed with high tidal level and the land height data is then generalized in model to calculate flooding areas. The maximum inundation area reaches 120 km2 and the total water level near sanmen nuclear power plant gets lower by 0.5m than that without inundation. The conclusion could provide scientific basis for the protection of the sanmen nuclear power plant and reclamation projects.

Language中文
Document Type学位论文
Identifierhttp://ir.qdio.ac.cn/handle/337002/156814
Collection海洋环流与波动重点实验室
Corresponding Author杨万康
Recommended Citation
GB/T 7714
杨万康. 典型海湾风暴潮的非线性与共振效应及其危险性评估研究[D]. 中科院海洋所. 中国科学院大学,2019.
Files in This Item:
File Name/Size DocType Version Access License
典型海湾风暴潮的非线性与共振效应及其危险(10933KB)学位论文 开放获取CC BY-NC-SAApplication Full Text
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Google Scholar
Similar articles in Google Scholar
[杨万康]'s Articles
Baidu academic
Similar articles in Baidu academic
[杨万康]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[杨万康]'s Articles
Terms of Use
No data!
Social Bookmark/Share
All comments (0)
No comment.
 

Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.