The response of climatic jump in summer in north china to global warming   总被引：1，自引：1，他引：0  

Huang Jiayou 《大气科学进展》2000,17(2):184-192

To reveal climatic variation over North China, the climatic jumps in summer in Beijing are analyzed using the data of precipitation of summer (June, July, August) during the period of 1841-1993, in which those missed before 1950 were reconstructed by the stepwise regression method with minimum forecast error. The climatic jumps at different scales are analyzed using different diagnostic methods with different decade (10-100 years) windows. Some new methods and ideas are proposed. The variance difference, the linear tendency difference, and the difference of power spectral distribution between the samples before and after the period at the moving point in the center of the series are compared with other methods (for example, Mann-Kendall test, t-test, and accumulative anomaly etc.). Considering the differences among the statistics above, a synthetic jump index is also proposed in order to get the definite jump points in the moving series. The results show that the climatic jumps in the area occurred in the 1890’s, the 1910s and the 1920s, and mostly in the 1920s, which suggests that the local climatic jumps in North China have a simultaneous response to the global warming in the hundred-year scales.  相似文献   

Estimation Of The Lagrangian Structure Function Constant C0 From Surface-Layer Wind Data     

D. Anfossi  G. Degrazia  E. Ferrero  S.E. Gryning  M.G. Morselli  S. Trini Castelli 《Boundary-Layer Meteorology》2000,95(2):249-270

Eulerian turbulence observations, madein the surface layer under unstable conditions (z/L > 0),by a sonic anemometer were used to estimatethe Lagrangian structure function constant _O. Twomethods were considered. The first one makes use of arelationship, widely used in the Lagrangian stochasticdispersion models, relating _O to the turbulent kineticenergy dissipation rate , wind velocity variance andLagrangian decorrelation time. The second one employsa novel equation, connecting _O to the constant of thesecond-order Eulerian structure function. Beforeestimating _O, the measurements were processed in orderto discard non-stationary cases at least to a firstapproximation and cases in which local isotropy couldnot be assumed. The dissipation was estimated eitherfrom the best fit of the energy spectrum in theinertial subrange or from the best fit of the third-orderlongitudinal Eulerian structure function. Thefirst method was preferred and applied to the subsequentpart of the analysis. Both methods predict thepartitioning of _O in different spatial components as aconsequence of the directional dependence of theEulerian correlation functions due to the isotropy.The _O values computed by both methods are presented anddiscussed. In conclusion, both methods providerealistic estimates of _O that compare well withprevious estimations reported in the literature, evenif a preference is to be attributed to the second method.  相似文献   

三峡水库汛期分期的变点分析方法研究   总被引：25，自引：3，他引：25  

刘攀郭生练  王才君张洪刚 《水文》2005,25(1):18-23

介绍了变点分析理论，结合三峡水库汛期的分期，阐述了均值变点、概率变点的理论与分析方法。采用宜昌站1882-2001年实测日流量资料，用均值变点分析方法对汛期每日最大洪峰构成的时间序列进行分期；同时选择一定的阈值，在假定发生概率服从二项分布的条件下，应用概率变点分析方法进行分期，最后给出了三峡水库汛期的分期方式。经比较表明，变点分析理论应用于汛期分期中，能反映来水的基本规律，具有一定的应用价值；但从理论上以及防洪的角度来讲，概率变点分析方法较均值变点方法更适于水库汛期的分期计算。  相似文献   

岩矿石物性参数的综合信息提取     

戴洪建  王信 《吉林地质》2005,24(2):96-100

探讨了区域物性参数统计整理方法，把概率论运用于物性参数统计中，提出参数幅度特征的概念。论述了多元物性参数的组合分析方法。为综合物理场的判断解释及项目设计阶段物探方法的有效选择提供了一种较有效的分析思路。  相似文献   

Seamless integration of spatial statistics and GIS: The S-PLUS for ArcView and the S+Grassland Links     

Shuming Bao  Luc Anselin  Doug Martin  Diana Stralberg 《Journal of Geographical Systems》2000,2(3):287-306

The extension of the functional capacity of geographic information systems (GIS) with tools for statistical analysis in general and exploratory spatial data analysis (ESDA) in particular has been an increasingly active area of research in recent years. In this paper, two operational implementations that combine the functionality of spatial data analysis software with a GIS are considered more closely. They consist of linkages between the S-PLUS software for data analysis and two different GIS implementations, the ArcView desktop system, which is mostly vector-oriented, and the primarily raster-based Grassland open GIS environment. We emphasize conceptual and technical issues related to the software implementation of these approaches and suggest future directions for linking spatial statistics and GIS. Received: 14 January 1999 / Accepted: 11 May 1999  相似文献   

基于GIS的贝叶斯统计推理技术在印度野牛生境概率评价中的应用     

张洪亮  李芝喜  王人潮  张军  孟鸣 《遥感学报》2000,4(1):66-70,83

首先给出ＣＯ２倍增下遥感－光合作物产量的概念模型,之后分析未受ＣＯ２倍增的遥感－光合作物产量估测模型;在考虑ＣＯ２倍增对作物产量的影响后,对影响干物质累积的作物光合速率的模型进行修正,进而修正遥感－光合作物产量估测模型。建立ＣＯ２倍增下作物产量影响模型,求取各参数,并在ＣＯ２倍增下对我国华北地区冬小麦产量影响进行填图,表明模型的估测结果有良好的可比性。  相似文献   

基于GIS的贝叶斯统计推理技术在印度野牛生境概率评价中的应用   总被引：11，自引：0，他引：11  

张洪亮  李芝喜  王人潮  张军  孟鸣 《遥感学报》2000,4(1):66-70,83

目前,ＧＩＳ技术已被广泛应用在野生动物生境研究中。但是,作为空间数据分析和处理工具,ＧＩＳ缺乏进行启发式推理的能力。因此,与擅长于此的贝叶斯统计推理技术相结合则是解决这一问题的重要途径。以西双版纳纳板河流域生物圈保护区为试验区,综合应用ＧＩＳ技术和多元统计技术建立印度野牛生境的两个逻辑斯蒂多元回归模型：趋势表面模型和环境模型,第一个模型的自变量是位置坐标,第二个模型的自变量是一组环境因子,然后应用贝叶斯统计合并这两个模型产生贝叶斯综合模型。结果表明,贝叶斯综合模型优于环境模型,可应用于野生动物生境概率评价。  相似文献   

T106产品夏季降水概率预报自动化系统   总被引：10，自引：2，他引：8  

牛叔超  朱桂林  李燕  刘月辉  朱宝来 《气象》2000,26(3):37-39

利用１０６格点场资料,构造能反映本地天气动力学牲的组合预报因子,对预报时效场进行叠加处理,对预报着急区格点资料取其均值或极值。预报因子和预报量均采用非线性０、１化自理。用最优子集回归建立降水预报方程用多因子概率权重回归其降水概率。系统从资料采集到输出概率结果在５８６以上微机上实现全自动化,预报结果客观、定量。  相似文献   

全球气候变暖对长江三角洲极端高温事件概率的影响   总被引：19，自引：1，他引：18  

邓自旺  丁裕国  陈业国 《南京气象学院学报》2000,23(1):42-47

研究了全球气候变暖对长江三角洲极端高温事件（ＥＨＴＥ）概率的影响。结果表明,全球增暖将使ＥＨＴＥ发生的概率增大。当夏季逐日平均最高气温在现有的基础上升高３．０℃后,ＥＨＴＥ发生的概率将由现在的０．１３增加到０．２～０．３,即夏季出现级端最高气温≥３５℃的天数将由现在的１２ｄ左右增加到２０～３０d。  相似文献   

Fragility curves for reinforced concrete structures in Skopje (Macedonia) region     

E. Dumova-Jovanoska   《Soil Dynamics and Earthquake Engineering》2000,19(6):314

A method for the development of earthquake intensity–damage relations, given as fragility curves and damage probability matrices is proposed in this paper. The proposed method is applied on reinforced-concrete frame-wall structures. Two sets of fragility curves and damage probability matrices are developed. The first one is for reinforced-concrete frame structures lower than 10 stories. For this purpose, a six-story frame structure is used. The other set is defined for reinforced-concrete frame-wall structures higher than 10 stories. A 16-story frame-wall structure was chosen as a sample. The sample structures were designed according to Macedonian design code. The conditions of the local seismic hazard were the subject of special concern for the development of earthquake intensity–damage relations. Because of the limited number of real time histories from the Skopje region, a set of 240 synthetic time histories were generated. Geological dates from the Skopje region were used. Response of the sample structures under earthquake excitation was defined performing nonlinear dynamic analysis. Modeling of the nonlinear behavior of the structural elements was completed according to state-of-the-art methods in this field. A modified Park and Ang damage model was chosen as a measure of the structure's response to earthquake excitation. Five damage states were defined to express the condition of damage. As a result of the analytical research, the values of the global damage index corresponding to each damage state were determined. Using the dates from the nonlinear dynamic analysis of the sample structures under all 240 synthetic time histories, the two sets of fragility curves and damage probability matrices were defined.  相似文献