Correlation of extreme waves and water levels using a third-generation wave model and a 3D flow model     

C.W. Li  Y. Song 《Ocean Engineering》2006,33(5-6):635-653

A procedure to correlate extreme wave heights and extreme water levels in coastal waters using numerical models together with joint probability analysis has been proposed. A third-generation wave model for wave simulation and a three-dimensional flow model for water level simulation are coupled through the surface atmospheric boundary layer. The model has been calibrated and validated against wind, wave and water level data collected in the coastal waters of Hong Kong. The annual maximum wave height and the concomitant water level have been obtained by simulating the annual extreme typhoon event for 50 consecutive years. The results from bivariate extreme value analysis of the simulated data show that the commonly used empirical method may lead to underestimation of the design water level.  相似文献   

Geophysical and hydrogeologic investigation of groundwater in the Karoo stratigraphic sequence at Sawmills in northern Matabeleland,Zimbabwe: a case history     

Jens E. Danielsen  Torleif Dahlin  Richard Owen  Pride Mangeya  Esben Auken 《Hydrogeology Journal》2007,15(5):945-960

Geophysical and hydrogeological investigations have been carried out around Sawmills in Zimbabwe, Africa. The investigations are components of a larger investigation to assess the groundwater potential of the Karoo sedimentary basin with regards to supplying water to Bulawayo City. The Sawmills area was selected due to the availability of borehole logs indicating favourable stratigraphy for groundwater availability and due to the high yields from the aquifers measured from these boreholes. Data collected using two geophysical methods are presented here: transient electromagnetic (TEM) and continuous vertical electrical sounding (CVES) data. The data have also been processed using laterally constrained inversion (LCI). Because the CVES provides greater detail in the shallow subsurface, whereas TEM is more effective at depth, a more accurate image of the entire subsurface profile is provided based on using both methods. The results suggest that LCI of CVES and TEM data, in the subsurface at the required depths at Sawmills, is able to provide a substantially more accurate image of the subsurface than either method alone. The hydrogeological interpretation of the geophysical data is valuable for determining the depth to and thickness of the potential aquifer horizon(s) and for identifying the position of potential recharge zones.  相似文献   

鳌江流域洪水预报调度决策支持系统   总被引：3，自引：0，他引：3       下载免费PDF全文

唐勇  胡和平  田富强  卢麾 《水科学进展》2003,14(3):295-299

位于浙江省温州市南部的鳌江是一条洪水灾害频繁的河流.介绍了鳌江流域洪水预报调度决策支持系统的总体设计、功能模块、逻辑结构、模型组织以及应用水文学及水力学的方法对流域洪水演进过程进行模拟计算的方法等,建立了一个可以在中小流域推广应用的防洪预报调度系统.  相似文献   

Engineering a Remote Survey of Jet's Divertor Structure Under Conditions of Restricted Access Using Digital Photogrammetry     

B. Macklin  R. Brade  F. Hurd  S. F Mills  S. Sanders  R. Stokes  & J. Tait 《The Photogrammetric Record》1998,16(92):213-223

JET (Joint European Torus) Joint Undertaking is currently planning to install its new Gasbox Divertor remotely. In line with JET's policy and philosophy, it was decided to survey the divertor structure remotely to confirm its position, shape and integrity prior to installing the new tile configuration. A survey to metrology standards with sub-millimetre accuracy is required. While remote surveys have been carried out in the past, they have not been to this level of accuracy. Digital photogrammetry (the evolution of photogrammetry, using CCD cameras) in conjunction with “targetless” software was selected as being the most suitable technique. It was seen as the natural evolution of the survey techniques already developed for use at JET, as well as having the potential to assist in preparations for future remote handling operations. Photogrammetry requires a large number of retroreflective targets to ensure accurate results. Clearly it would not be practical to fit targets remotely to the divertor structure. However, a technique has been developed at JET which uses a combination of targeted and targetless photogrammetry. A number of frames fitted with targets will be remotely positioned on the divertor structure. When surveyed these targets allow accurate determination of camera positions. Specially developed software allows the selection of untargeted features of components in the digital pictures. Their co-ordinates can be determined by triangulation from the known camera positions. Trials have shown that accuracy of ±0.6 mm is achievable. This paper will describe the development of this concept, the design of the necessary equipment, the testing to prove the accuracy and feasibility and the trials carried out in JET's In-vessel Training Facility. These included remote handling of the six million pixel camera and other equipment, data handling and download via an ethernet link through the remote handling articulated boom, development of survey techniques, optimization of analysis techniques using coded targets for fast processing and finally the engineering assessment of the divertor structure based on survey results.  相似文献   

基于局域网和拨号网络的电子邮件公文收发系统          下载免费PDF全文

张军  郭豫晋  荆肖军  赵玮 《山西气象》2004,(4):36-38

基于局域网和拨号网络的电子邮件公文收发系统彻底地改变了传统的信息传输方式，使用户能自动通过局域网或拨号网络收发邮件、浏览页面，极大地提高了地区与县局及服务单位之间传递公文、分发服务产品的效率，使上下级的信息交流更加直观、经济、便捷。  相似文献   

岩体风化的综合分带研究   总被引：23，自引：4，他引：23  

聂德新  韩爱果  巨广宏 《工程地质学报》2002,10(1):20-25

岩体的风化不仅会引起岩石物质成份、化学成份变化 ,而且也引起岩体裂隙、岩体完整性的改变。因而风化岩体中裂隙数量、岩体块度的变化与岩体的风化程度具有较好的对应关系。论文研究了用岩体裂隙间距、岩体的完整性指标、岩石质量指标对岩体风化程度进行分带 ,较好地将岩体风化分带与岩体结构、岩体工程特性紧密地结合起来。在岩体风化程度的定量划分上作了新的探索。  相似文献   

新疆伽师强震区余震序列的地震台阵定位   总被引：3，自引：2，他引：3       下载免费PDF全文

郭飙  刘启元  陈九辉  李顺成 《地震地质》2002,24(2):199-207,T001

1998年中国地震局地质研究所在伽师强震群区布设了 30台流动宽频带地震台 ,记录到比纳木及龙口两个强震 (M≥ 6 0 )的主震及余震序列。我们利用Geiger法和JHD方法对这两个地震序列进行了台阵定位。结果表明 :1)利用地震台阵数据的JHD定位结果可以较好地确定地震序列的相对空间位置 ,并且比Geiger法有更高的精度 ;2 )比纳木、龙口地震序列勾画出了两条不平行的SWW向断层 ,其走向及产状与相应主震的矩张量研究结果基本吻合 ,此地震序列可作为确定伽师强震群震源断层面的重要参考依据 ;3)比纳木和龙口地震序列发生在壳幔界面的梯度带上及壳内高、低速介质交界部位 ,这表明地震的形成与地壳深部构造环境密切相关 ;4 )伽师强震群具有张性破裂特征 ,其主要原因是塔里木盆地北缘的横向非均匀变形  相似文献   

地震定位研究综述   总被引：36，自引：2，他引：36  

田玥  陈晓非 《地球物理学进展》2002,17(1):147-155

综述了各种地震定位方法的基本原理，重点介绍了Geiger的经典方法以及在此基础上建立的各种线性方法：联合定位法，相对定位法，和最新的双重残差法；对每一种方法的应用情况，尤其是国内的工作做了总结；同时也指出了各种方法的特点，并进行了相应的比较，此外，还简要介绍了空间域的定位方法和各种非线性定位方法。  相似文献   

利用深反射地震数据构建的多阶面波频散曲线反演近地表横波速度结构——以跨班公湖—怒江缝合带深反射地震资料为例          下载免费PDF全文

张辉  刘志伟  贺日政  李巧灵 《地球物理学报》1954,63(12):4410-4430

深反射地震剖面法为了获取深部结构特征常常采取大的偏移距采集数据.目前公开发表的相关资料中,鲜有利用深反射地震炮集数据获取近地表的结构特征.为此,本文通过正演测试了相关数据处理流程,即利用有限差分正演了起伏地表模型的大偏移距地震单炮弹性波场特征,通过共检波点域面波信号F-K频谱叠加构建新方法,从深反射地震数据集中提取了高品质的多阶面波频散曲线,再利用多阶面波联合反演获得了近地表的结构特征.在前述正演流程基础上,利用跨越班公湖—怒江缝合带的SinoProbe深反射地震剖面中的实际炮集数据,求取了基阶和一阶瑞利波频散曲线,联合反演后得到近地表横波速度结构.该结果与初至波走时反演获取的纵波速度结构具有较好的一致性,且在近地表的浅层分辨率较纵波速度结构特征更高,而更与已有地质认识相吻合.本文提供的相关数据处理流程表明利用深反射地震炮集数据,也能够获取近地表浅层的横波速度结构.  相似文献   

岩体断裂粗糙度系数的各向异性研究   总被引：2，自引：1，他引：2  

杜时贵  唐辉明 《工程地质学报》1993,1(2):32-42

本文首次提出了断裂粗糙度系数的各向异性和粗糙度系数尺寸效应的各向异性概念。根据不同成因断裂表面形态的定性分析结果,结合2180个不同方向粗糙度系数实测值的统计结果,系统地阐述了Ⅰ型断裂(节理)和Ⅱ、Ⅲ型断裂(断层)粗糙度系数及粗糙度系数尺寸效应的各向异性规律。  相似文献