工程养护海滩对"803"风暴潮的响应过程研究     

朱磊  杨燕雄  杨雯  房克照 《海洋通报》2019,38(1):102-14

研究养护海滩对风暴潮的响应过程在人工养滩工程设计与施工中具有重要意义。老龙头养护海滩在竣工半个月后遭遇“803”风暴潮，导致岸滩滩肩最大蚀退 6.5 m，沙坝坝顶最大下蚀 1.2 m。在现场测量的基础上，利用 XBeach 建立风暴潮过程 的老龙头海滩海床演变模型，研究结果表明： （1） XBeach 模拟结果与实际地形变化侵淤趋势一致，风暴潮期间人工沙坝均向岸移动，但模拟结果的侵蚀程度更大，海滩响应更加剧烈； （2） 强浪条件下人工沙坝的透射系数为 0.29~0.42，常浪条件下透射系数为 0.45~0.95，因而人工沙坝在大浪条件下掩护作用更佳； （3） 风暴潮期间人工沙坝附近破波显著，坝顶流速明显增大，最大可达 1.21 m/s，是无人工沙坝情况下的 2.3 倍，而在人工沙坝向岸侧，因波能提前耗散，流速减为 0.28 m/s，是无人工沙坝时的 0.4 倍，且没有产生离岸流。老龙头养护工程整体泥沙损失较少，易于恢复.  相似文献   

A simplified hindcast method for the estimation of extreme storm surge events in semi-enclosed basins     

《Applied Ocean Research》2019

Human presence, coastal erosion, and tourism activities are increasing the attention to coastal flooding risk. To perform risk assessments, long time series of observed or hindcast wave parameters and tide levels are then necessary. In some cases, only a few years of observation are available, so that observed extreme data are not always representative and reliable. A hindcast system aimed to reconstruct long time series of total tide levels may be of great help to perform robust extreme events analysis and then to protect human life, activities as well as to counteract coastal erosion by means of risk assessments. This work aims to propose a simplified method to hindcast storm surge levels time series in semi-enclosed basins with low computational costs. The method is an extension of a previous work of some of the authors and consists of a mixed approach in which the estimation of storm surge obtained by using the theory of linear dynamic system is corrected by using a statistical method. Both steps are characterized by low computational costs. Nevertheless, the results may be considered reliable enough also in view of the simplicity of the approach. The proposed method has been applied to the Manfredonia case study, a small village located in the Southern Adriatic Italian coast and often prone to coastal flooding events. The comparison of extreme events estimated on the basis of hindcast levels time series is satisfactorily similar to those estimated on the basis of observed tide series.  相似文献   

一种风暴轴逐日监测的方法及应用   总被引：1，自引：1，他引：0  

顾聪  朱伟军 《气象科学》2015,35(3):268-278

提出了一种风暴轴逐日监测的方法, 可以获得逐日的风暴轴变化情况。并且采用了动态阈值定义了新的风暴轴的强度和位置指数, 从而可以有效对比不同层次、不同区域、不同时间的风暴轴变化情况。利用NCEP/NCAR再分析资料进行了监测结果的诊断分析。结果表明:各气象要素滤波结果都能表现出两个风暴轴主体, 但有位置上的差别。同时可以利用逐日检测的结果求得逐候、逐月的风暴轴监测结果。在不同高度的风暴轴中, 250~300 hPa高度的风暴轴强度最大, 850 hPa有极小值出现, 各层风暴轴强度呈现准正压结构。采用500 hPa高度场风暴轴监测结果做代表, 讨论了两大洋上各自的风暴轴偏强/偏弱、偏东/偏西、偏北/偏南时同期大气环流的500 hPa高度场和300 hPa纬向风场差异。  相似文献   

地面沉降对渤海湾风暴潮灾害防治的影响研究     

王威  周俊  易长荣 《城市地质》2011,6(4):31-35

渤海湾沿海地区地面沉降严重、风暴潮灾害频发。本文以天津作为典型区域,对风暴潮潮位测定、风暴潮灾害和防风暴潮预案措施等方面开展研究,认为地面沉降对上述3方面均有的不同程度的影响,在风暴潮灾害防治中必须考虑地面沉降问题。  相似文献   

Appraisal of storm beach buffer width for cyclonic waves     

F.-C. Lee  John R.-C. Hsu  W.-H. Lin 《Coastal Engineering》2011

The loss of beach sand from berm and dune due to high waves and surge is a universal phenomenon associated with sporadic storm activities. To protect the development in a coastal hazard zone, hard structures or coastal setback have been established in many countries around the world. In this paper, the requirement of a storm beach buffer, being a lesser extent landward comparing with the coastal setback to ensure the safety of infrastructures, is numerically assessed using the SBEACH model for three categories of wave conditions in terms of storm return period, median sand grain size, berm width, and design water level. Two of the key outputs from the numerical calculations, berm retreat and bar formation offshore, are then analysed, as well as beach profile change. After having performed a series of numerical studies on selected large wave tank (LWT) test results with monochromatic waves using SBEACH, we may conclude that: (1) Berm erosion increases and submerged bar develops further offshore as the storm return period increases for beach with a specific sand grain size, or as the sand grain reduces on a beach under the action of identical wave condition; (2) Higher storm waves yield a large bar to form quicker and subsequently cause wave breaking on the bar crest, which can reduce the wave energy and limit the extent of the eroding berm; (3) A larger buffer width is required for a beach comprising small sand grain, in order to effectively absorb storm wave energy; and (4) Empirical relationships can be tentatively proposed to estimate the storm beach buffer width, from the input of wave conditions and sediment grain size. These results would benefit a beach nourishment project for shore protection or design of a recreational beach.  相似文献   

一次强烈雹暴的多普勒天气雷达资料分析   总被引：4，自引：2，他引：2  

王丛梅  景华  王福侠  王丽荣 《气象科学》2011,31(5):659-665

利用石家庄多普勒天气雷达资料和常规探测资料,对2008年5月17日发生在河北南部的强烈雹暴的生成环境和动力机制以及发展演变特征进行了分析。内蒙古东部冷涡后部的冷空气和低层暖湿气流在河北中南部交汇,导致这个地区上空的层结不稳定,低层的暖切变和地面的东风辐合线为触发系统。高低空急流、不稳定层结、强垂直风切变为强烈雹暴的发生提供了有利的环境条件。强烈雹暴的多普勒天气雷达观测特征表现为一个次超级单体的发展移动过程,呈现回波悬垂和弱回波区特征,强回波核区反射率因子达到73 dBz,三体散射现象明显,对应径向速度图表现为弱中气旋,旋转速度为15 m/s。次超级单体右移特征明显,沿承载层平均风方向偏右侧移动。风暴相对螺旋度(Srh)大值与强雹暴的产生密切相关,0.3～2.1 km的Srh正值出现以及2.1～6.1 km的Srh减小随后迅速增加对冰雹的预报有很好的指示意义。  相似文献   

风暴相对螺旋度与强对流天气类型的关系分析   总被引：3，自引：0，他引：3       下载免费PDF全文

石燕茹  寿绍文  王丽荣  杨荣珍  赵严厂 《气象与环境学报》2011,27(1):65-71

对风暴相对螺旋度(SRH)的定义进行了介绍.通过对2007-2008年石家庄地区27次强对流天气过程的统计分析,找出短时暴雨、冰雹和大风任意组合时高、低层SRH的不同特征,得到不同天气现象的预报指标,并利用2009年的几次强对流天气过程进行了验证.结果表明:出现短时暴雨时,SRH低经常连续较长时间为正值,但数值较小,S...  相似文献   

Deterministic and ensemble storm surge prediction for Atlantic Canada with lead times of hours to ten days     

《Ocean Modelling》2015

Regional deterministic and ensemble surge prediction systems (RDSPS and RESPS respectively) are used to forecast sea levels off the east of Canada and northeast US. The surge models for the RDSPS and RESPS have grid spacings of 1/30° and 1/12° respectively. The models are driven by surface air pressure and 10 m winds generated by operational global deterministic and ensemble prediction systems that are run operationally by the Canadian Meteorological Centre. Surge forecasts are evaluated for the period 1 March, 2013 to 31 March 2014. Based on traditional statistics (e.g., standard deviation of the difference between observations and predictions) both systems are shown to have skill in forecasting surges six days into the future. It is shown however that skill exists beyond six days if allowance is made for errors in the timing of large surges. The usefulness of the RESPS is demonstrated for two positive surges (important for coastal flooding and erosion) and a negative surge (important for safe navigation in shallow water). It is shown that the RESPS can identify events not forecast by the RDSPS, and can also add useful additional information on the timing of the surge, an important consideration in tidally dominated waters. Several new types of display are used to illustrate the sort of information that can be generated by the RESPS to support the issuers of warnings of unusually high and low total water levels.  相似文献   

Combined Ozone and Biological Treatment of Oak Wood Leachate          下载免费PDF全文

Henric Svensson  Henrik Hansson  William Hogland 《洁净——土壤、空气、水》2015,43(4):598-604

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Rapidly installed temporary gauging for hurricane waves and surge,and application to Hurricane Gustav     

Andrew B. Kennedy  Uriah Gravois  Brian Zachry  Rick Luettich  Tony Whipple  Robert Weaver  Janelle Reynolds-Fleming  Qin J. Chen  Roni Avissar 《Continental Shelf Research》2010

Hurricanes can produce extreme nearshore waves and surge, but permanent gauging stations are often much sparser than is desired. This paper describes the rationale behind and outline for rapidly installed temporary coastal gauges, and presents results during Hurricane Gustav (2008). Within 48 h prior to landfall, twenty self-recording pressure gauges were deployed in depths of 1.4–23 m over more than 700 km of coastline, using helicopters to cover the large distances. Results showed a complex picture that was strongly dependent on location. East of the Mississippi Delta, open coast waves were large, and surge reached 3.8 m NAVD88 in marshes. West of the delta but near landfall, waves and surge were generally smaller as the river levees blocked flow from East to West. West of landfall, both waves and surge were very small and the most prominent feature was a water level drawdown that reached 1.5 m. Wave spectra varied strongly depending both on location and time from landfall.  相似文献