灌溉水利用效率的空间分布特征及等值线图研究

Spatial Distribution of Irrigation Water Use Efficiency and Its Isogram

基于全国各行政区的现状灌溉水利用效率数据,采用地质统计学及空间自相关分析方法对灌溉水利用效率的空间分布特性进行分析。结果表明:空间自相关法得到现状灌溉水利用效率在1500 km范围内各方向上存在着较明显的自相关关系,总体上没有较显著的方向性,但在ES-WN方向上的自相关性起主要作用。灌溉水利用效率各向同性条件下变异函数可用指数模型描述,在1900 km空间范围内存在着显著的相关性,除ES-WN方向外,并未体现明显的各向异性,与空间自相关分析结论基本一致。理论变异参数的分析结果表明,灌溉水利用效率的空间变异主要是结构性因素起决定作用,结构性变异达到91%左右。对比灌溉水利用效率及代表影响指标的空间分布格局可知,ET0均值、年均降水量对于灌溉水利用效率的影响是间接的,灌溉水利用效率与节水灌溉工程面积比存在显著正相关关系。

Data of current irrigation water use efficiency （IWUE） of administrative area in China were collected and its spatial distribution is analyzed using geostatistical and spatial autocorrelation approaches. The results of spatial autocorrelation analysis indicate that positive autocorrelation of IWUE extends to about 1500 km and the directionality is not obvious on the whole while the autocorrelation in the direction of ES-WN play a main role. The isotropic variogram of IWUE can be described with sphere model. The results from geostatistical approach show that the IWUE exhibits significant spatial autocorrelation within the range of 1900 km. and there is no remarkable anisotropic except in the ES-WN direction, which are consistent with the results from spatial autocorrelation approach. The analytical result of model parameter shows that the spatial variability of IWUE is mainly influenced by structure factors and the structural variability reaches about 91%. Comparing the spatial distribution pattern of IWUE with representative impact indexes, it is found that the influence of average ETo and annual precipitation is indirect and the proportion of water saving irrigation project area has significant positive correlation relationship with IWUE.