基于Copula函数的河南省干旱特征分析

基于河南省及周边26个站点降水资料,采用降水距平百分率识别干旱事件,统计了干旱历时和干旱烈度两个干旱特征变量,利用四种Copula函数建立了干旱历时和干旱烈度的联合分布,选取拟合度最优的Copula函数,通过空间插值法得到河南省干旱联合重现期空间分布,分析了干旱重现期的空间分布特征。结果表明,干旱联合重现期低值(干旱风险高)区在河南省南部,如南阳、信阳一带;干旱联合重现期高值(干旱风险低)区分布在河南省西部,如三门峡、栾川等地区。

Analysis of Characteristics of Drought in Henan Province Based on Copula Function

According to the precipitation data of 26 sites in Henan Province and around area, the percentage of precipitation was used to identify the drought event, which was defined and described by two drought characteristic variables, i.e., drought duration and drought severity. Four kinds of Copula functions were established to express the joint distribution of drought duration and drought severity. Then, fitting results of all Copula functions were compared, and the best fitting Copula function was employed to analyze the spatial distribution characteristics of return period of drought by spatial interpolation method. The results show that the regions with low joint return period of drought, i.e., with high risk for drought, are located in the south of Henan Province, such as Nanyang, Xinyang and so on, while the regions with high joint return period of drought, i.e., with low risk for drought, are located in the west of Henan Province, such as Sanmenxia, Luanchuan and so on.