集雨农业降水资源评估方法的研究

利用降水和地形资料，建立了定西县及其邻近的２５个观测站点的栅格数字高程模型（ＤＥＭ）、各测站近３４年的实测降水量及其相关信息空间数据库。采用统计模型、空间插值和综合方法，模拟了研究区３４年的年平均降水量、降水变率、降水保证率、丰水年和欠水年的年均降水量，以及雨季（７￣９月）和春小麦生长时期（３月中旬￣７月中旬）的降雨量空间分布，用５个观测站点的降水资料对各种模拟方法进行了精度评估。并且，在不同的空

Research on the Estimation Methods of Precipitation Resource for Rain harvesting Agriculture

Based on the rainfall data and topographic maps at 25 observation stations around Dingxi County, the grid digital elevation models(DEM) in the related areas and the spatial database of annual average precipitation(AAP) and relative information in the late 34 years at each station were established. According to the statistics, spatial interpolations and comprehensive methods, the spatial distributions and changes of AAP for 34 years, AAP coefficients of variation, AAP under different rainfall probabilities, AAP in arid and humid years and average rainfall in rainy seasons and growing seasons for spring wheat were modelled. At the same time, simulated precision of each method was estimated by 5 test stations, and the AAP was calculated by using the above databases on different scales(i.e, villages and catchments in the related areas). Results indicated that the comprehensive method had the highest simulation precision in the 9 approaches(inverse distance weighted, trend, spline, ordinary Kriging, universal Kriging one, universal Kriging two, multi variable regression and comprehensive methods), its maximum relative error was 6.895%. The next was ordinary Kriging method, and its maximum error reached to 6.756%. As far as the 7 interpolation approaches were concerned, the precision of ordinary Kriging method was the best. The error of statistical model was relatively high, of which the maximum relative error was 9.041%. The AAP estimation system established by the measured and predicted rainfall spatial databases could quickly and timely calculate the spatial distributions and changes on any scales in the related areas, and it had an important influence in the agricultural engineering planning, development strategy and decision making as well as water management in rain harvesting agriculture.