Numerical simulation of typhoon-induced storm surge along Jiangsu coast,Part Ⅰ:Analysis of tropical cyclone

The Tropical Cyclone Best Track Dataset issued by the Shanghai Typhoon Institute of the China Meteorological Administration, for the period from 1949 to 2013, was analyzed, and the typhoons threatening the Jiangsu coast were categorized into three different classes in terms of track, including typhoons making straight landfall, typhoons active in offshore areas, and typhoons moving northward after landfall. On the basis of the 65-year dataset, the typhoon parameters of these three categories, including the central pressure and the maximum wind speed, were investigated. Statistical analysis suggested that the minimum central pressure increased northward and shoreward gradually. The relationship between the maximum wind speed and the minimum central pressure was established through second-order polynomial fitting. Considering typhoons No. 1210, No. 0012, and No. 9711 as the basic typhoons, ten hypothetical cyclones with typical tracks and minimum central pressure occurring during the period from 1949 to 2013 were designed, providing the driving conditions for numerical simulation of typhoon-induced storm surges along the Jiangsu coast.     

Spatio-temporal distribution characteristics and influencing mechanisms of storm surge in Guangdong. Hong Kong and Macao Greater Bay AreaEI北大核心CSCD

基于1970—2018年珠江口潮位站历史潮位资料，结合风暴潮数值模拟结果，统计分析了粤港澳大湾区风暴潮的时空分布特征并探讨了风暴潮增水影响机理。结果表明：在空间分布上，伶仃洋、狮子洋、前航道等区域出现较大增水的频率较高，与该区域特殊的地理位置及伶仃洋河口湾漏斗状形态产生的能量辐聚有关，增水极值与台风登陆地点和台风强度均有关系；风暴潮发生时间主要集中在7—9月，占全年总次数的74.4%；影响粤港澳大湾区的强台风以上级别的台风频次增加趋势明显，各站点历年最高潮位呈增加趋势，平均速率为0.02~0.03m/a；台风路径对风暴潮增水的空间分布有较大影响，当台风在大湾区西岸登陆，距离台风登陆点约2.5倍最大风速半径的位置可产生较大的增水值；最大增水随着台风中心压强的降低而升高，中心压强每下降10hPa，最大增水值上升0.4~1.1m；当台风移动速度接近8.3m/s，珠江口形成较为稳定的风暴潮水位梯度，产生较大的风暴潮增水。     

Prediction of Hydraulic Stability of Francis Turbines of Three Gorges Hydropower Station

1　ＩｎｔｒｏｄｕｃｔｉｏｎＯｐｅｒａｔｉｎｇｓｔａｂｉｌｉｔｙｉｓｔｈｅｉｍｐｏｒｔａｎｔｇｕａｒａｎｔｅｅｏｆａｔｕｒ ｂｏｇｅｎｅｒａｔｏｒｕｎｉｔ ｓｌｏｎｇ ｔｅｒｍａｎｄｓａｆｅｏｐｅｒａｔｉｏｎ．Ｔｈｅｔｕｒｂｏ ｇｅｎｅｒａｔｏｒｕｎｉｔｏｆｔｈｅＴｈｒｅｅＧｏｒｇｅｓｈｙｄｒｏｐｏｗｅｒｓｔａｔｉｏｎｉｓｏｎｅｏｆｔｈｅｌａｒｇｅｓｔｔｕｒｂｏｇｅｎｅｒａｔｏｒｕｎｉｔｓｉｎｔｈｅｗｏｒｌｄ，ｗｉｔｈｉｔｓｔｕｒｂｉｎｅ ｓｒａｔｅｄｏｕｔｐｕｔｏｆ 710ＭＷ，ｍａｘｉｍｕｍｏｕｔｐｕ…     

Analysis of Hydrologic Property of Poyang Lake

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State of the “dam-foundation” system during operation of the outlet of the chirkey hydroelectric station

Conclusions  

Analysis of Micro Organic Compound Pollution in Major City River Reaches of the Main Stem of the Changjiang River

1　ＳｔｕｄｙＡｒｅａｓａｎｄＳｔｕｄｙＭｅｔｈｏｄｏｌｏｇｙ1.1　ＳａｍｐｌｉｎｇＡｒｅａｓａｎｄＳａｍｐｌｅＴｙｐｅｓＡｌｌｔｈｅｓａｍｐｌｅｓｗｅｒｅｃｏｌｌｅｃｔｅｄｆｒｏｍｍａｉｎｓｔｅｍｃｒｏｓｓ-ｓｅｃｔｉｏｎｓａｎｄｎｅａｒｓｈｏｒｅｗａｔｅｒｓｏｆ 2 2ｍａｊｏｒｃｉｔｙｒｉｖｅｒｒｅａｃｈｅｓｏｆＰａｎｚｈｉｈｕａ ,Ｙｉｂｉｎ ,Ｌｕｚｈｏｕ ,Ｃｈｏｎｇｑｉｎｇ ,Ｆｕｌｉｎｇ ,Ｗａｎｘ ｉａｎ ,Ｙｉｃｈａｎｇ ,Ｓｈａｓｈｉ,Ｙｕｅｙａｎｇ ,Ｗｕｈａｎ ,Ｅｚｈｏｕ ,Ｈｕａｎｇ ｓｈｉ,Ｊ…     

“Rosshelf” company and development of the arctic shelf of Russia

Power Technology and Engineering -     

Optimization of parabolic bars for maximum Bragg resonant reflection of long waves

This paper presents an analytical solution for the problem of the long wave reflection by a series of artificial bars with parabolic configuration in terms of the associated Legendre functions. It is shown that both the reflection and transmission coefficients depend solely upon the number of bars, the dimensionless bar height, the dimensionless bar width and the dimensionless bar distance. Particularly, under the Bragg resonance condition, i.e., the distance between two adjacent bars is about half of the wavelength of the normal incident waves, the analytical solution for the peak Bragg resonant reflection is obtained, which reveals that the peak Bragg resonance depends upon the number of bars, the dimensionless bar height and the dimensionless bar width. Based on this solution, the optimization of the parabolic bars is made to obtain the maximum Bragg resonance and a group of optimal curves, which may be very useful in the design of Bragg breakwaters with parabolic bars.     

基于台风参数模型的江苏海域风暴增减水研究

以正面袭击江苏的"达维"台风为例,运用台风参数模型、第三代波浪模型和基于浅水方程水动力模型对台风期间江苏沿海的风暴增减水进行模拟研究。首先,运用Je氏台风参数模型模拟了台风的梯度风场,并与NECP再分析风场数据对"达维"台风场进行合成,与观测值进行比较,拟合结果良好;然后,以模拟的台风风场为驱动,模拟台风经过期间江苏海域的波浪场,同时计算台风期间江苏海域的天文潮;最后,运用浅水方程计算江苏海域的增减水,并研究了沿海增减水分布情况。研究结果表明:灌河口附近最大风暴增水达1.9 m左右,由于台风中心位置的影响,江苏沿海最大增水从北往南呈先增大后递减的趋势。     

海平面上升背景下辐射沙脊风暴潮增水研究

海平面上升将对沿海环境构成严重威胁,风暴潮灾害频发和加剧是其中的重要表现。相关研究揭示水深和潮波变化是引起风暴潮增水与海平面上升之间非线性关系的两大主要因素。在地形和潮波系统较为复杂的苏北辐射沙脊海域这种非线性关系尤为明显。总结了该海域潮波、风暴潮特征和海平面变化趋势,利用WRF模式和Delft 3D风暴潮模式相结合,建立了东中国海和南黄海二维天文潮-风暴潮耦合数学模型。分析研究了海平面上升以后,相同路径和强度的两种典型台风作用下,辐射沙脊海域风暴增水极值和高潮位变化。分析结果表明:海平面上升后,辐射沙脊海域增水作用普遍减弱,近岸较外海明显;而在辐射沙脊中、南部,海平面上升对天文潮高潮位的增强作用要强于对风暴增水的减弱作用。     

Numerical simulation of typhoon-induced storm surge along Jiangsu coast,Part I: Analysis of tropical cyclone

The Tropical Cyclone Best Track Dataset issued by the Shanghai Typhoon Institute of the China Meteorological Administration, for the period from 1949 to 2013, was analyzed, and the typhoons threatening the Jiangsu coast were categorized into three different classes in terms of track, including typhoons making straight landfall, typhoons active in offshore areas, and typhoons moving northward after landfall. On the basis of the 65-year dataset, the typhoon parameters of these three categories, including the central pressure and the maximum wind speed, were investigated. Statistical analysis suggested that the minimum central pressure increased northward and shoreward gradually. The relationship between the maximum wind speed and the minimum central pressure was established through second-order polynomial fitting. Considering typhoons No. 1210, No. 0012, and No. 9711 as the basic typhoons, ten hypothetical cyclones with typical tracks and minimum central pressure occurring during the period from 1949 to 2013 were designed, providing the driving conditions for numerical simulation of typhoon-induced storm surges along the Jiangsu coast.     

“达维”台风作用下连云港海域台风浪数值模拟

为准确模拟"达维"台风过境期间连云港海域波浪场分布,采用Jelesnianski风场模式模拟的海面10m风速作为波浪模式MIKE-SW的驱动风场,再现1210号"达维"台风登陆连云港海域波浪变化过程。模拟计算结果表明,Jelesnianski风场模式成功复演了"达维"台风过境期间风动力变化过程,1210号"达维"台风与1209号"苏拉"台风形成明显的双台风效应;"达维"台风风暴潮期间,连云港海洋站最大风暴增水1.78m,连云港海域风暴增水现象十分明显;利用三重网格嵌套技术,考虑实时风暴潮增水效应的台风浪模型能够较好地模拟连云港近海波浪成长过程,台风过境期间徐圩海洋站处H1/3波高最大值为3.86m,近岸海域波高等值线分布较为密集,分布趋势与水下地形等深线基本一致,破波带以内水域衰减速度明显加快,与连云港海域属于淤泥质海岸类型的性质相吻合。     

香港沿岸台风暴潮灾害联合强度概率分析

以香港东部鲗鱼涌和大埔滘两个验潮站的风暴增水数据为基础,以1999-2018年影响香港的台风过程所引发的风暴最大增水为研究对象,利用广义极值分布分别对两站的最大台风增水进行一元拟合,并基于二元Copula函数,构造两站最大台风增水的联合概率分布,根据其联合重现频率进行潮灾的联合强度概率分析。研究结果表明:两站台风暴潮最大增水变量的联合重现频次能够反映台风在香港东部引发的风暴潮的强度,这种联合概率分析较一元分析有更强的地区适用性。     

“烟花”台风影响下长江南通以下河段的增水分布特征

为探讨台风对河口区域的影响,构建了覆盖中国东南沿海大范围数学模型,对2106号台风“烟花”产生的风暴潮进行了模拟,与实测气象及水位数据对比表明该模型可靠、合理。基于此模型,研究了“烟花”台风在长江口地区风暴潮增水的时空分布特征。研究表明,“烟花”台风期间,长江口区域整体表现为增水状态,最大增水大于0.5 m区域北至连云港、南至台州。南通以下河段最大增水值分布较均匀,均在1.5 m左右;上游区域增水幅度随潮汐过程呈规律波动,增水在涨潮中间时刻达到最大,于落潮中间时刻降至最低,至下游区域,波动规律逐渐消失;0.5 m以上增水历时从上游至下游逐渐减小。     

Effects of cluster land reclamation projects on storm surge in Jiaojiang Estuary,China

Variations in coastline geometry caused by coastal engineering affect tides, storm surges, and storm tides. Three cluster land reclamation projects have been planned for construction in the Jiaojiang Estuary during the period from 2011 to 2023. They will cause significant changes in coastline geometry. In this study, a surge-tide coupled model was established based on a three-dimensional finite-volume coastal ocean model (FVCOM). A series of numerical experiments were carried out to investigate the effects of variations in coastline geometry on tides, storm surges, and storm tides. This model was calibrated using data observed at the Haimen and Ruian gauge stations and then used to reproduce the tides, storm surges, and storm tides in the Jiaojiang Estuary caused by Typhoon Winnie in 1997. Results show that the high tide level, peak storm surge, and high storm tide level at the Haimen Gauge Station increased along with the completion of reclamation projects, and the maximum increments caused by the third project were 0.13 m, 0.50 m, and 0.43 m, respectively. The envelopes with maximum storm tide levels of 7.0 m and 8.0 m inside the river mouth appeared to move seaward, with the latter shifting 1.8 km, 3.3 km, and 4.4 km due to the first project, second project, and third project, respectively. The results achieved in this study contribute to reducing the effects of, and preventing storm disasters after the land reclamation in the Jiaojiang Estuary.     

Coupled modelling of storm surge,circulation and surface waves in a large stratified lake

The wind-driven nature of large lakes suggests that the accuracy of meteorological inputs is essential for hydrodynamic modelling. Moreover, coupling between the meteorological inputs and density stratification may also influence the simulated lake behavior. To investigate wind-driven large lake processes, a high-resolution coupled Delft3D-SWAN model was applied to Lake Ontario to simulate storm surges, surface waves, and circulation during two recent storm events. In both events, the sustained wind speeds approached 20 m s^?1; however, variations in wind direction and duration altered the lake's surface wave and storm surge responses. The influence of different atmospheric inputs was investigated by comparing results from two spatially varied atmospheric models: the Rapid Refresh (RAP) and the High-Resolution Deterministic Prediction System (HRDPS). Hydrodynamic simulations using HRDPS were marginally better, with maximum root mean squared errors (RMSE) between modelled and observed water levels of 0.07 m, compared to 0.08 m with RAP. Predictions of the magnitude and timing of the maximum wave heights varied based on wind fields, with differences between predicted peak wave heights of up to 0.4 m. Both events occurred during a stratified period, allowing for a comparative evaluation of the influence of baroclinic and barotropic processes on the simulated surface wave and storm surge results. Simulations including the vertical density gradient gave a better representation of current velocities with depth and resulted in an improved prediction of peak storm surge magnitudes and surface water level behavior following the storms, reducing the RMSE by up to 12%.     

潮汐河口闸下风暴潮特征模拟

潮汐河口闸下风暴潮水位对于河道防洪排水至关重要。以苏北里下河主要入海通道射阳河、黄沙河、新洋河和斗龙河等建闸河口为例,采用模型嵌套的方法,以平面二维数学模型模拟了里下河地区“9711”台风风暴潮期间闸下河段的潮汐水流和风暴潮运动过程,研究了闸下风暴潮水位相对河口风暴潮水位的变化特征。模拟结果显示,底摩擦、浅水变形、边界反射等相互作用影响,闸下风暴潮水位和潮汐水位存在一致的变化特性,即高潮位抬升,低潮位下降,潮差(增水)增加;涨潮历时缩短,落潮历时延长;风暴潮水位的变化幅度大于同时期的潮汐水位,风暴潮过程对于闸下排水具有显著影响。在与闸顶高程一致的上游水位条件下,相比天文潮过程,“9711”风暴潮过程可减少闸门过流流量的20%~25%。