区域气象干旱评估分析模式

Research of the regional meteorological drought assessment analysis model

为应对全球范围内日益严重的干旱问题,对区域气象干旱相对完整的评估分析模式开展了探讨。提出了从区域气象干旱识别到干旱特征值计算,再到干旱特征多变量分析的3个分析评估步骤。并以渭河流域为例,对研究区域进行了矩形干旱评估单元划分,选取了RDI(Reconnaissance Drought Index)为评估指标对区域内各单元各时段的干旱状态进行了识别,结果与历史记载的干旱年份吻合较好。分别采用了分布拟合、相关系数和Copula函数等统计学方法对区域干旱的干旱特征值(干旱历时、干旱面积、干旱强度和干旱频率)进行了特征分析,得出了一系列的单变量、双变量及多变量特征分析对比结果。通过对各类分布函数的计算和绘图,得到了渭河流域干旱事件发生的条件概率和重现期,形成了一套相对完整的区域干旱评估分析模式。

In order to cope with the increasingly serious global drought issue, this treatise investigates the relatively complete evaluation and analysis model on the regional meteorological drought. It proposes a three-step evaluation and analysis method, which includes the regional meteorological drought identification, the drought characteristic value calculation and the multivariable analysis on drought characteristics. Taking Weihe River basin as a case study example, the treatise first carries out a rectangular drought evaluation-unit division on the research area, selecting reconnaissance drought index as an evaluation indicator to identify drought conditions in each unit at different time periods in the research area. The result is almost in accordance with the historical record on the years of drought. Then the treatise uses statistical methods such as the distribution fitting, the correlation coefficient, the copulas function to carry out characteristic analysis on the regional drought characteristic values （the drought duration, the drought area, the drought severity and the drought frequency）, drawing a series of analytic and comparative results on the univariate, the bivariate and the multivariate characteristics. Based on the distribution function calculation and construction on different distribution functions, the treatise comes to the occurrence conditional probability and recurrence interval of droughts in Weihe Basin, forming a relatively complete evaluation and analysis model on the regional meteorological drought.