城市供水管网在地震时的连通可靠性分析

考虑地震作用效应和管道抗力的随机特性,建立了埋地管道单元的概率预测模型,评估其在地震时的震害状态。把供水管网系统简化为边权有向网络图,通过Monte Carlo随机模拟过程,近似再现管网中各管段的破坏状态,进而分别结合图论理论方法和模糊关系矩阵法,对管网进行连通可靠性分析。由于Monte Carlo模拟算法是以管网各节点与水源点处于连通状态的近似频率计算来代替精确概率分析,为获得稳定的计算结果,对所用算例进行了5000次模拟。算例分析表明,基于图论方法和模糊关系矩阵法得到的管网连通可靠性结果基本相等。     

侏罗系镍钒元素纵向、平面分布特点及有利区预测

为了研究镍钒元素分布特点及其与油气藏的关系,统计分析了准噶尔盆地各层（不合地表）岩心、岩屑和原油中镍和钒元素的含量,发现在泥岩的镍、钒含量最大、砂岩的次之、油样和油砂（沥青）的较小,试油结果也有同样的结论;剖面上来说,侏罗系和二叠系（烃源岩层）的镍、钒含量较大,大于别的层至少一个数量级;对单井而言,当试油结果为油水同层或含油水层时,镍钒含量大,纯油层反而小,说明水层对微量元素的贡献是增大的正效应,油层是负效应;单井试油结论为纯水,那么该层的镍钒比值就小于1.最后指出A至G镍钒元素的低值区是油气勘探的有利区.     

Seasonal drought predictability in Portugal using statistical–dynamical techniques

Atmospheric forecasting and predictability are important to promote adaption and mitigation measures in order to minimize drought impacts. This study estimates hybrid (statistical–dynamical) long-range forecasts of the regional drought index SPI (3-months) over homogeneous regions from mainland Portugal, based on forecasts from the UKMO operational forecasting system, with lead-times up to 6 months. ERA-Interim reanalysis data is used for the purpose of building a set of SPI predictors integrating recent past information prior to the forecast launching. Then, the advantage of combining predictors with both dynamical and statistical background in the prediction of drought conditions at different lags is evaluated. A two-step hybridization procedure is performed, in which both forecasted and observed 500 hPa geopotential height fields are subjected to a PCA in order to use forecasted PCs and persistent PCs as predictors. A second hybridization step consists on a statistical/hybrid downscaling to the regional SPI, based on regression techniques, after the pre-selection of the statistically significant predictors. The SPI forecasts and the added value of combining dynamical and statistical methods are evaluated in cross-validation mode, using the R² and binary event scores. Results are obtained for the four seasons and it was found that winter is the most predictable season, and that most of the predictive power is on the large-scale fields from past observations. The hybridization improves the downscaling based on the forecasted PCs, since they provide complementary information (though modest) beyond that of persistent PCs. These findings provide clues about the predictability of the SPI, particularly in Portugal, and may contribute to the predictability of crops yields and to some guidance on users (such as farmers) decision making process.     

组合预测模型在女性呼气高峰流量参考值地理分布研究中的应用

随着地理学的发展以及人们对健康问题的日益关注,医学地理学得到迅速发展。鉴于目前医学参考值制定时仍存在忽略地理因素的影响,本文收集中国各地3809 例健康成年女性呼气高峰流量参考值,分析地理因素对其的影响,计算不同地区参考值的数值差异,探究地理因素对医学参考值产生影响的机理,其中,纬度、海拔高度、年平均气温、年平均相对湿度、年降水量、表土砂砾百分率、表土参考容量共7项地理因素存在显著的相关性。利用ArcGIS中的Moran's I指数对数据进行分析,确定数据与空间及地理因素存在关系。并通过岭回归分析,建立回归方程,并进行插值。研究结果表明,中国健康成年女性肺部呼气高峰流量与纬度与海拔、气候、土壤等地理因素之间存在着显著的关系,同时证明,岭回归与支持向量机组合模型的地理分布差异预测结果优于单独预测方法。     

Forecasting flash floods using data-based mechanistic models and NORA radar rainfall forecasts

Abstract

Data-based mechanistic (DBM) models can offer a parsimonious representation of catchment dynamics. They have been shown to provide reliable accurate flood forecasts in many hydrological situations. In this work, the DBM methodology is applied to forecast flash floods in a small Alpine catchment. Compared to previous DBM modelling studies, the catchment response is rapid. The use of novel radar-derived ensemble quantitative precipitation forecasts based on analogues to drive the DBM model allows the forecast horizon to be increased to a level useful for emergency response. The characterization of the predictive uncertainty in the resulting hydrological forecasts is discussed and a framework for its representation illustrated.

Editor Z.W. Kundzewicz; Guest editor R.J. Moore     

两种背景场改进方案对新疆“狭管”风区风场预报性能评估

为了客观评价Wind Energy Resource Assessment System /CMA(简称WERAS/CMA)系统(CTL方案)和将其中的客观分析法改成四维同化系统(简称FDDA方案)对既受狭管效应影响、又受湖陆风影响的阿拉山口和达坂城-小草湖风区起伏下垫面中的风能资源数值模拟的优劣,根据2009年7、10月和2010年1、4月 12UTC的NCEP再分析资料以及同期CMACAST下发的WMO各种常规观测资料开展了风场预报效果对比实验。结果表明:(1)对复杂区域而言,两种方案比过去单纯只用中尺度模式进行风场模拟的平均相对误差至少减小10%;(2)总体而言,两种方案对70 m高度处的风速模拟误差要大于30、50、100 m处的误差,在受多种环流尺度影响区域,模式在刻画平均风速/风向频率廓线方面的缺陷均极其相似;(3)在70 m高度上,两种方案5 m·s^-1以内的风速平均相对误差可达60%～130%,>5 m·s^-1的误差可控制在15%以内;对受湖陆风影响区域的模拟误差明显偏大,误差大小与湖陆风效应的季节变化有关; (4)两种方案均能抓住70 m左右高度上不同等级风速段的气候背景,对达坂城风区5～15 m·s^-1风速段的Ts预报评分可达0.6～0.7,对阿拉山口和小草湖风区≤5 m·s^-1风速段的Ts预报评分分别可达0.6～0.7和0.9左右。然而,对达坂城风区≤5 m·s^-1风速段的Ts预报评分仅0.3～0.4;(5)两种方案对所有风区需采取停机保护措施的、15 m·s^-1以上强风预报的Ts评分仅在0.4～0.6;(6)同一测风塔不同高度上,FDDA方案对风的预报效果不一定总优于CTL方案,但在70 m高度上,FDDA总体略优于CTL;即使同一风区,各个测风塔之间两种方案的预报效果也是因局地多尺度环流影响的不同或因预报的高度不同或预报季节的不同而异,这种预报误差差异的机理还有待探究。     

基于卡尔曼滤波算法的焦炭价格预测

焦炭价格预测研究具有重要的理论和实践意义,本文利用卡尔曼滤波算法对焦炭价格进行预测研究。建立状态空间模型时,选取焦炭价格作为唯一的状态变量,通过每一时刻变量观测值与预测值形成的新息,不断更新和迭代,以寻求最优估测值。实证分析表明,该算法对焦炭价格的跟踪和预测效果较好。     

利用T213物理量“垂叠法”模型制作沙澧河上游关键区面雨量预报

利用沙澧河流域上游关键区2003-2006年6-8月降水资料和同时段T213产品中预报产品,分析了关键区强降水发生前24h T213产品中比湿、相对湿度、水汽通量、水汽通量散度、假相当位温、垂直速度等物理量垂直空间结构特征,并根据不同特征,构建T213物理量"垂叠法"暴雨和大雨预报模型,对沙澧河流域上游关键区分别作大雨以上(面雨量≥20mm)和暴雨以上(面雨量≥40mm)强降水预报。通过检验和试用,该预报模型对2007-2009年6-8月沙澧河流域上游关键区面雨量≥20mm强降水预报准确率平均达54.2%,对面雨量≥40mm强降水预报准确率平均为38.9%。