洪水影响预报和风险预警理念与业务实践   总被引：2，自引：0，他引：2       下载免费PDF全文

刘志雨 《水文》2020,40(1):1-6

我国是世界上洪涝灾害频繁而严重的国家之一,洪水预报预警是防汛减灾工作中重要的非工程措施和洪水防御工作的耳目和参谋。从水文行业的视角,回顾了近年来我国洪水预报预警技术与业务进展,分析了当前洪水预报预警工作面临的新形势和新要求,对比国内外同类行业发展查找了存在的差距,阐述了洪水影响预报和风险预警的定义和理念,从顶层对基于影响预报和风险预警的新一代洪水预报预警系统("国家洪水预报预警系统")总体框架进行了研究和设计,一些关键技术成果在大范围洪水早期预警业务实践中得到了探索应用,取得了较好的效果。  相似文献   

Location and probability of shoal margin collapses in a sandy estuary          下载免费PDF全文

Wout M. van Dijk  Dick R. Mastbergen  Geeralt A. van den Ham  Jasper R. F. W. Leuven  Maarten G. Kleinhans 《地球表面变化过程与地形》2018,43(11):2342-2357

Channel bank failure, and collapses of shoal margins and beaches due to flow slides, have been recorded in Dutch estuaries for the past 200 years but have hardly been recognized elsewhere. Current predictions lack forecasting capabilities, because they were validated and calibrated for historic data of cross‐sections in specific systems, allowing local hindcast rather than location and probability forecasting. The objectives of this study were to investigate where on shoal margins collapses typically occur and what shoal margin collapse geometries and volumes are, such that we can predict their occurrence. We identified shoal margin collapses, generally completely submerged, from bathymetry data by analyzing digital elevation models of difference of the Western Scheldt for the period 1959–2015. We used the bathymetry data to determine the conditions for occurrence, specifically to obtain slope height and angle, and applied these variables in a shoal margin collapse predictor. We found 299 collapses along 300 km of shoal margin boundaries over 56 years, meaning that more than five collapses occur on average per year. The average shoal margin collapse body is well approximated by a 1/3 ellipsoid shape, covers on average an area of 34 000 m² and has an average volume of 100 000 m³. Shoal margin collapses occur mainly at locations where shoals take up a proportionally larger area than average in the cross‐section of the entire estuary, and occur most frequently where lateral shoal margin displacement is low. A receiver operating characteristic curve shows that the forecasting method predicts the shoal margin collapse location well. We conclude that the locations of the shoal margin collapses are well predicted by the variation in conditions of the relative slope height and angle within the Western Scheldt, and likely locations are at laterally relatively stable shoal margins. This provides hypotheses aiding the recognition of these features in sandy estuaries worldwide. Copyright © 2018 John Wiley & Sons, Ltd.  相似文献   

2020年6月26日新疆于田6.4级地震前中期和短期预测依据与启示     

宋治平  薛艳  马亚伟  宋春燕  张小涛  晏锐  孟令媛  闫伟  苑争一 《中国地震》2020,36(3):407-416

2020年6月26日新疆于田6.4级地震发生在2020年度全国地震危险区内，震前作出了较好的中期（年度）和短期（月尺度和周尺度）预测，是少有的地球物理观测能力较低地区的强震前中期和短临预测较好震例。本文梳理了中期和短期预测的主要依据及其预测效能，研究表明，震前中期异常主要有流动地磁、多方法组合、5.0级地震平静打破、6.0级地震的准周期活动等；短期异常有4.0级地震活动图像、中源地震影响、于田垂直摆倾斜EW、于田GNSS基准站EW位移、和田GNSS基准站EW位移等。在总结震前分析预测过程的基础上，提出针对地球物理观测密度低地区的地震危险区论证和短临跟踪的建议，为该类地区的地震危险区判定及跟踪工作提供宝贵经验。  相似文献   

Parametric uncertainty assessment of hydrological models: coupling UNEEC-P and a fuzzy general regression neural network   总被引：1，自引：1，他引：0  

Arman Ahmadi  Dimitri P. Solomatine 《水文科学杂志》2019,64(9):1080-1094

Due to the complicated nature of environmental processes, consideration of uncertainty is an important part of environmental modelling. In this paper, a new variant of the machine learning-based method for residual estimation and parametric model uncertainty is presented. This method is based on the UNEEC-P (UNcertainty Estimation based on local Errors and Clustering – Parameter) method, but instead of multilayer perceptron uses a “fuzzified” version of the general regression neural network (GRNN). Two hydrological models are chosen and the proposed method is used to evaluate their parametric uncertainty. The approach can be classified as a hybrid uncertainty estimation method, and is compared to the group method of data handling (GMDH) and ordinary kriging with linear external drift (OKLED) methods. It is shown that, in terms of inherent complexity, measured by Akaike information criterion (AIC), the proposed fuzzy GRNN method has advantages over other techniques, while its accuracy is comparable. Statistical metrics on verification datasets demonstrate the capability and appropriate efficiency of the proposed method to estimate the uncertainty of environmental models.  相似文献   

基于热层电离层耦合数据同化的热层参量估计   总被引：1，自引：0，他引：1       下载免费PDF全文

何建辉  乐新安 《地球物理学报》2020,63(7):2497-2505

本文采用高效集合卡尔曼滤波(EnKF)算法和背景场热层电离层理论模式NCAR-TIEGCM,开发了热层电离层数据同化系统.基于全球空地基GNSS电离层斜TEC观测、CHAMP和TIMED/GUVI热层参量观测构型设计了系列观测系统模拟实验,对热层参量进行估计.实验结果表明,(1)通过集合卡尔曼滤波算法同化电离层TEC观测能够较好地优化热层参量.(2)中性质量密度优化效果在整个同化阶段均有提升,提升百分比能达到40%.(3)积分氧氮比在同化阶段也能得到较好的优化,但在电子密度水平梯度变化剧烈区域效果较差.最后本文对中性质量密度进行了预报评估,结果表明,由于中性成分优化,在地磁平静条件下其预报时间尺度可长达24h.  相似文献   

Groundwater contaminant source identification based on iterative local update ensemble smoother          下载免费PDF全文

YANG Ai-lin  JIANG Si-min  LIU Jin-bing  JIANG Qian-yun  ZHOU Ting  ZHANG Wen 《地下水科学与工程》2020,8(1):1-9

Identification of the location and intensity of groundwater pollution source contributes to the effect of pollution remediation, and is called groundwater contaminant source identifcation. This is a kind of typical groundwater inverse problem, and the solution is usually ill-posed. Especially considering the spatial variability of hydraulic conductivity field, the identification process is more challenging. In this paper, the solution framework of groundwater contaminant source identification is composed with groundwater pollutant transport model (MT3DMS) and a data assimilation method (Iterative local update ensemble smoother, ILUES). In addition, Karhunen-Loève expansion technique is adopted as a PCA method to realize dimension reduction. In practical problems, the geostatistical method is usually used to characterize the hydraulic conductivity feld, and only the contaminant source information is inversely calculated in the identifcation process. In this study, the identification of contaminant source information under Kriging K-field is compared with simultaneous identification of source information and K-field. The results indicate that it is necessary to carry out simultaneous identification under heterogeneous site, and ILUES has good performance in solving high-dimensional parameter inversion problems.  相似文献   

State estimation of tidal hydrodynamics using ensemble Kalman filter     

《Advances in water resources》2014

This paper presents a coupling of an ensemble Kalman filter (EnKF) with a discontinuous Galerkin-based, two-dimensional circulation model (DG ADCIRC-2DDI) to improve the state estimation of tidal hydrodynamics including water surface elevations and depth-integrated velocities. The methodology in this paper using EnKF perturbs the modeled hydrodynamics and bottom friction parameterization in the model while assimilating data with inherent error, and demonstrates a capability to apply EnKF within DG ADCIRC-2DDI for data assimilation. Parallel code development presents a unique aspect of the approach taken and is briefly described in the paper, followed by an application to a real estuarine system, the lower St. Johns River in north Florida, for the state estimation of tidal hydrodynamics. To test the value of gauge observations for improving state estimation, a tide modeling case study is performed for the lower St. Johns River successively using one of the four available tide gauging stations in model-data comparison. The results are improved simulations of water surface elevations and depth-integrated velocities using DG ADCIRC-2DDI with EnKF, both locally where data are available and non-locally where data are not available. The methodology, in general, is extensible to other modeling and data applications, for example, the use of remote sensing data, and specifically, can be readily applied as is to study other tidal systems.  相似文献   

全过程联合校正方法在饶河流域洪水预报中的应用研究     

王钦钊  黄一昕  梁忠民  邓晓栋 《水文》2021,41(2):45-50

为提高饶河流域洪水预报精度,将全过程联合校正(EPJC)方法与三水源新安江(XAJ)模型结合,按一定比例划分洪水预报总误差为各过程误差,基于系统响应理论反演得到面雨量计算误差和模型参数误差,重新输入流域水文模型正演得出校正后的洪水过程。选取洪峰流量相对误差、峰现时间绝对误差、径流深相对误差和确定性系数作为模型评价指标,量化XAJ预报与EPJC校正结果,并与传统的动态系统响应曲线(DSRC)方法进行对比。结果表明,EPJC能够考虑全过程误差,与实际误差分布情况更相符,可提升饶河流域的洪水作业预报精度,值得进一步研究与推广。  相似文献   

我国无缝隙精细化网格天气预报技术进展与挑战   总被引：5，自引：2，他引：3       下载免费PDF全文

金荣花  代刊  赵瑞霞  曹勇  薛峰  刘凑华  赵声蓉  李勇  韦青 《气象》2019,45(4):445-457

本文总结了2014年以来我国无缝隙精细化网格天气预报业务的技术进展,讨论了未来发展所面临的关键技术难点。无缝隙精细化网格预报技术的发展,得益于综合气象观测数据和多源资料融合分析网格实况产品的支撑,更依赖于多尺度数值预报模式和实时快速更新同化预报系统的快速发展。经过近5年的探索和努力,我国已经初步建立了针对不同预报时效的无缝隙精细化网格预报技术体系。对于0～4 h预报时效,主要基于全国雷达拼图和GRAPES-Meso模式预报,发展临近分钟级滚动外推预报技术;对于4 h到30 d预报时效,主要通过对区域或全球不同时空分辨率模式预报进行偏差订正、客观解释应用以及降尺度分析,提高预报的准确度和精细度。与此同时,研发了自动化、智能化的交互式预报制作平台,以满足客观高效制作与预报员对极端或高影响天气主观预报优势相结合的需求。发展了以格点实况分析场为参照的空间分析检验方法,初步实现了对高分辨率网格预报的质量跟踪和性能评估。未来的网格预报技术体系,需要吸纳前沿的技术研究成果,包括人工智能应用技术、高级多模式统计后处理技术和协调一致性关键技术等,并且建立统一完整的技术架构和开发标准等。  相似文献   

飞机积冰预报算法对比及其集成预报模型研究     

卞双双  何宏让  安豪  潘晓滨  张云 《气象》2019,45(10):1352-1362

以人工增雨作业获取的飞机积冰实例资料为基础,利用WRF模式对51次飞机积冰过程进行数值模拟,对比分析了常用七种积冰预报算法对积冰潜势区和强度的预报效果,进而采用评分权重集成法建立了飞机积冰强度集成预报模型,并检验了其预报效果。结果表明:(1)假霜点温度经验法对2002年4月4日积冰个例的预报效果与实况一致,而其他积冰算法预报效果均与实况相差较大;(2)对51次飞机积冰预报效果进行统计检验发现,假霜点温度经验法的预报效果最好,积冰强度预报准确率为72.55%,其次是RAOB法,IC指数法和I积冰指数法次之,改进的IC指数法预报准确率最差,只有19.61%;(3)对比不同积冰算法建立的集成预报模型的预报效果发现,选用IC指数法、假霜点温度经验法、RAOB法进行集成预报时,预报准确率最高,且漏报率、偏弱率及偏强率均能控制在10%以内,比单一预报算法中的最高预报准确率提高了8%,且漏报率降低了4%,偏强率降低了8%。  相似文献