2010年汛期多模式对山东降水预报的检验

为提高数值预报模式在山东汛期降水的预报能力,为降水预报及模式物理参数方案选择和调整提供客观依据,对2010年汛期（6-9月）山东区域MM5、WRF-RUC（WRF快速循环同化系统）和T639模式24 h、48 h累积降水预报产品,进行晴雨、一般性降水和分量级降水TS评分及平均绝对误差、平均误差分析。结果表明：从晴雨预报准确率来看,3种模式相差不大;一般性降水和小雨预报,MM5模式评分结果最差,T639模式预报效果最好;中雨以上量级,24 h降水T639模式预报效果最好,特别是24 h大暴雨评分T639模式达到了10.37 %,而48 h降水T639模式预报效果下降明显。无论24 h降水还是48 h降水,除9月WRF-RUC模式平均绝对误差最小外,6-8月T639模式平均绝对误差均为最低,WRF-RUC模式24 h和48 h降水各月平均误差均为负偏差;不同的降水预报检验方案和天气过程类型对检验结果有一定的影响。     

新疆快速更新循环数值预报系统预报能力检验评估

对新疆快速更新循环数值预报系统2009年1、12月和2010年1、4、7、10月份的降水量和气温进行了检验,并与不做同化的预报结果进行了对比,得到以下结果：（1）降水Ts评分北疆好于南疆,偏西好于偏东,其中北疆西部、北部、北疆沿天山一带、天山山区、南疆西部山区最好。漏报率的分布表现为北疆沿天山一带、天山山区较小,南疆、东疆较大。空报率的情况为：南疆、东疆普遍较高,北疆沿天山一带较低,其他地区居中。（2）典型个例检验发现降水落区预报有较好的参考价值,但大降水中心位置的预报能力不稳定,和田、巴州南部的空报现象比较突出。（3）温度预报准确率南疆、东疆总体偏低,北疆西部、北部较高,其他地区居中,个别山区站存在较大误差。（4）现行新疆快速更新循环数值预报系统的预报能力不比不采用同化高。     

Prediction of ground subsidence in Samcheok City,Korea using artificial neural networks and GIS

This study shows the construction of a hazard map for presumptive ground subsidence around abandoned underground coal mines (AUCMs) at Samcheok City in Korea using an artificial neural network, with a geographic information system (GIS). To evaluate the factors governing ground subsidence, an image database was constructed from a topographical map, geological map, mining tunnel map, global positioning system (GPS) data, land use map, digital elevation model (DEM) data, and borehole data. An attribute database was also constructed by employing field investigations and reinforcement working reports for the existing ground subsidence areas at the study site. Seven major factors controlling ground subsidence were determined from the probability analysis of the existing ground subsidence area. Depth of drift from the mining tunnel map, DEM and slope gradient obtained from the topographical map, groundwater level and permeability from borehole data, geology and land use. These factors were employed by with artificial neural networks to analyze ground subsidence hazard. Each factor’s weight was determined by the back-propagation training method. Then the ground subsidence hazard indices were calculated using the trained back-propagation weights, and the ground subsidence hazard map was created by GIS. Ground subsidence locations were used to verify results of the ground subsidence hazard map and the verification results showed 96.06% accuracy. The verification results exhibited sufficient agreement between the presumptive hazard map and the existing data on ground subsidence area. An erratum to this article can be found at     

VERIFICATION OF MATHEMATICL MODEL FOR SEDIMENT TRANSPORT BY UNSTEADY FLOW IN THE LOWER YELLOW RIVER

Field data from the Lower Yellow River (LYR) covering a period often consecutive years are used to test a mathematical model for one dimensional sediment transport by unsteady flow developed previously by the writers. Data of the first year of the said period, i.e., 1976, are used to calibrate the model and those of the remaining years to verify it. Items investigated include discharge, water stage, rate of transport of suspended sediment and riverbed erosion/deposition. Comparisons between computed and observed data indicate that the proposed model may well simulate sediment transport in the LYR under conditions of unsteady flow with sufficient accuracy.     

Numerical simulation and land subsidence control for deep foundation pit dewatering of Longyang Road Station on Shanghai Metro Line 18

In terms of controlling groundwater in deep foundation pit projects, the usual methods include increasing the curtain depth, reducing the amount of pumped groundwater, and implementing integrated control, in order to reduce the drawdown and land subsidence outside pits. In dewatering design for confined water, factors including drawdown requirements, the thickness of aquifers, the depth of dewatering wells and the depth of cutoff curtains have to be considered comprehensively and numerical simulations are generally conducted for calculation and analysis. Longyang Road Station on Shanghai Metro Line 18 is taken as the case study subject in this paper, a groundwater seepage model is developed according to the on-site engineering geological conditions and hydrogeological conditions, the excavation depth of the foundation pit as well as the design depth of the enclosure, hydrogeological parameters are determined via the pumping test, and the foundation pit dewatering is simulated by means of the three-dimensional finite difference method, which produces numerical results that consistent with real monitoring data as to the groundwater table. Besides, the drawdown and the land subsidence both inside and outside the pit caused by foundation pit dewatering are calculated and analyzed for various curtain depths. This study reveals that the drawdown and the land subsidence change faster near the curtain with the increase in the curtain depth, and the gradient of drawdown and land subsidence changes dwindles beyond certain depths. In this project, the curtain depth of 47/49 m is adopted, and a drawdown-land subsidence verification test is completed given hanging curtains before the excavation. The result turns out that the real measurements basically match the calculation results from the numerical simulation, and by increasing the depth of curtains, the land subsidence resulting from dewatering is effectively controlled.     

COMPARISON BETWEEN RESULTS OF MODEL TESTS AND OBSERVED DATA FOR THE FLUCTUATING BACKWATER REGION OF THE GEZHOUBA RESERVOIR

The fluctuationg backwater region of a reservoir has a twofold property of a river as well as a reservoir and undergoes scouring and deposition alternately. Phys- ical model simulating the fluvial processes in a fluctuating backwater region has to ensure the similarities of both scouring and deposition. This causes some difficulties in model design and the selection of model sediment. This paper describes the model study of the fluctuating backwater region of the Gezhouba Project on the Yangtze River. Plastic particles with specific gravity of 1 .056 are used. The physical. model covers a reach of mountainous river 130 km in length. The experimental results show that the total amount of deposit, its distribution along the reach, the size distribution of the deposit, and lengths of the backwater region for various discharges all agree very well with the measured data in reservoir after 5 years of operation. This fact indicates that the model design, including the selection of model sediment, is quite acceptable.     

Long term sediment transport simulation of the Danube,Sava, and Tisa rivers

The aim of this paper is to evaluate a newly developed one dimensional unsteady flow, sediment transport and bed evolution model for a looped river network through a long term simulation of a real-life scenario. The model was assessed by verifying it for the Danube, Tisa, and Sava rivers in Serbia for a five year time interval. The total length of the modeled domain was 741.94 km from which 486.48 km is the length of the modeled Danube River reach, 132.50 km the modeled section of the Sava and 122.96 km the length of the modeled Tisa River reach. The simulated domain included smaller tributaries such as the Kolubara, Mlava, Nera, Pek, Porecka, Tamis, and Great Morava rivers. Due to the size of the domain that was included in the model, the work also includes extensive research regarding the available measurements, issues with measurement errors, and suggestions on overcoming incomplete measurements by developing different types of correlations. The attained results were analyzed by comparing the simulation results with measured water levels, discharges, and suspended sediment concentrations. The implemented evaluation of the results confirmed the developed model's reliability.     

岩体随机不连续面三维网络模型的检验

岩体随机不连续面三维网络模拟技术成熟与否的一个重要标志就是最终的网络模型是否能够较真实地再现岩体的实际情况,为了使三维网络模型的结果能够真正地应用于实际工程,就必须对模拟的结果进行必要的检验,检验的办法就是将模拟出的模型剖面图形与原型测量窗口的图形进行图形对比,或者将原型的观测数据与模型的测试数据进行数据对比,当这种检验达到精度时,模拟出的模型为有效模型,可以投入工程实际应用。     

一种基于可预报性的暴雨预报评分新方法Ⅱ:暴雨检验评分模型及评估试验

针对当前暴雨预报检验采用二分类事件检验方法存在较严重的“空报”“漏报”双重惩罚,没有考虑暴雨时空分布不均和预报评分可比性不够等问题,在分析预报员对暴雨预报评分期望值基础上,设计了一种基于可预报性的暴雨预报检验评分新方法和计算模型,分析了理想评分,并对2015-2016年4-10月中国中央气象台5 km×5 km定量降水格点预报和降水落区等级暴雨预报进行评分试验,获得了以下结果和结论:（1）预报员对暴雨预报评分期望值呈现梯级下降特征,与传统的TS评分存在显著差异;（2）设计了一种基于可预报性的暴雨预报检验新方法,通过引入e指数函数构建暴雨预报评分基函数,进而构建暴雨评分模型,该模型可以较好地拟合预报员对暴雨预报评分的期望值,同时改善了评分在不同量级阈值处的断崖式突变情况;（3）提出了预报与观测的邻域匹配方法,即一个预报点与所定义邻域中的一组观测相匹配,并利用距离加权最大值法确定暴雨评分值权重系数,预报与观测距离越近,距离权重系数越大,评分值权重越大,提高了评分的合理性,避免了距离较远的匹配站点得高分不利于鼓励预报员提高预报精度的问题;（4）对中国中央气象台逐日5 km×5 km水平分辨率的定量降水格点预报产品和中央气象台定量降水落区等级预报产品进行了评分试验,暴雨预报准确率全国平均值大于60分。基于可预报性的暴雨预报检验新评分与传统暴雨预报TS评分逐日演变特征相似,但可以较好地解析TS为0的预报评分,解析后的新评分与预报员和公众的心理预期更为接近。      

2008年T213与德国降水数值预报产品对比检验分析

为了解各种数值预报的误差特点,更好地在预报过程中选择数值预报产品作为参考依据,将中国国家气象中心的T213降水预报和德国降水预报分别进行晴雨预报检验,对2008年5—8月期间东北地区降水资料进行对比分析。结果表明：两种模式24—120h预报正确率为60%—70%左右,随着预报时效的增加,正确率呈下降趋势,德国降水预报的正确率高于T213,两种预报漏报率均明显小于空报率,T213漏报率较低,为5%左右,德国降水预报空报率较低,为20%左右。对2008年4—6月出现东北冷涡过程的两种模式降水预报进行对比分析,发现德国降水预报正确率明显高于T213预报,对冷涡降水预报有一定的指示意义。