灌区降水量与参考作物腾发量的联合分布模型研究

Joint distribution model of precipitation and reference crop evapotranspiration in irrigation area

为从系统和风险的新角度描述灌溉系统的两个基本变量,在分析参考作物腾发量研究现状的基础上,以宁夏卫宁灌区为例,基于灌区降水量和参考作物腾发量之间具有的天然相关性,首先应用P-III曲线法推求得到二者的频率分布曲线,再运用Copula函数方法构建了降水量和参考作物腾发量年际联合分布模型,给出了降水量和参考作物腾发量的重现期等值线图,为灌溉系统的规划和风险评价提供了新的技术支撑。

The relationship between two basic variables of irrigation system from the new aspects of the system and the risk is described and on the basis of analyzing the current research on the reference crop evapotranspiration, both of the frequency distribution curves of the precipitation and the reference crop evapotranspiration are derived by applying P-III frequency curve calculation method at first based on the natural coorelation between them by taking Weining Irrigation Area in Ningxia as a study case, and then the annual joint distribution model of precipitation and reference crop evapotranspiration is con- structed through Copula method, furthermore, the isoline maps of the recurrence period of the precipitation and reference crop evapotranspiration therein are given; which provides a brand-new basic technological support for planning and risk as- sessment of irrigation system.