多年平均降水资源空间变化模拟方法的研究

Simulating methods of average annual rainfall on spatial changes

区域多年平均降水量的研究是集水农业工程规划的基础 ,也是有限的降水资源合理利用和配置的依据。研究利用 ARC/INFO地理信息系统 ,建立了研究区的栅格数字高程模型( DEM)及近 30年的年均降水量空间数据库 ;采用 9种算法 (距离权重法、趋势面法、样条函数法、普通 Kriging法、通用 Kriging方法 1、通用 Kriging方法 2、泰森多边形法、多元回归法和综合方法 ) ,计算并比较分析了研究区多年平均降水量的时空变化。研究结果表明 ,在平均降水量模拟的 9种算法中 ,综合方法的计算精度最高 ,其最大相对误差为 6.395% ;其次为普通 Kriging法 ,其最大相对误差为 6.756%。在 7种插值算法中 ,采用指数模型模拟半异矩的普通 Kriging法计算精度较高 ,统计模型的误差最大 ,其最大相对误差为 9.0 4 1 %。利用模拟精度最优的栅格降水空间数据库 ,建立的多年平均降水资源信息系统 ,可快速计算研究区内任一地域单元中降水的总量及其空间变化 ,对集水农业径流资源模拟、工程规划、发展战略及决策管理 ,均具有重要的意义。

Study on the spatial changes of Average Annual Rainfall (AAR) is not only a basis of the engineering planning for rain harvesting agriculture,but also an important index for the reasonable utilization of limited rainfall water resources.Using ARC/INFO GIS technology,the raster Digital Elevation Model (DEM) and the average annual rainfall databases for nearly 30 years in the study areas were established.By means of 9 methods (Inverse distance weighted,trend,spline,ordinary Kriging,Universal Kriging 1,Universal Kriging 2,multivariable regression,and comprehensive approach),the spatial and temporal changes of AAR were calculated and comparatively analyzed.Results indicated that simulating precision of the comprehensive method is the best one in the 9 approaches,and its maximum relative error is 6.395%,the next is ordinary Kriging method with exponential model to simulate semivariogram,and its maximum relative error reaches to 6.756%.As far as the seven kinds of interpolation approaches are concerned,the precision of ordinary Kriging method is the best one,and the error of statistical model is relatively high,of which the relative error reaches to 9.041%.The AAR information system,established by raster rainfall spatial databases using optimized methods,can quickly and timely calculate the total quantity and its spatial changes on any scales in the study areas,which has an important role in runoff simulating,engineering planning,strategy developing,and decision making as well as management for rainfall harvesting agriculture.