沂蒙山区降雨侵蚀力空间分布推算方法
Calculating methods of rainfall erosivity spatial distribution in Yimeng Mountain Area
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摘要: 以沂蒙山区88 个雨量站点1980—2010 年日降水数据为基础,采用普通克里格法和回归克里格法对多年平均降雨侵蚀力进行空间插值预测,分析评价不同空间插值方法预测结果的精度及差异性,掌握沂蒙山区降雨侵蚀力及空间分布特征。结果表明:1)2 种方法降雨侵蚀力插值结果空间分布规律一致,但回归克里格法对局部变异性描述更为精确;回归克里格法降雨侵蚀力预测值与实算值接近,降雨侵蚀力预测相对精度较普通克里格法提高53.64%。2)沂蒙山区降雨侵蚀力最大值为5 438.22 MJ·mm/ (hm2·h·a),最小值3 033.23 MJ·mm/ (hm2·h·a),均值4 133.92 MJ·mm/ (hm2·h·a);半方差函数分析显示,年均汛期降雨量和年均侵蚀性降雨量是影响降雨侵蚀力空间变异的主要因素。3)沂蒙山区降雨侵蚀力空间分布上遵循从南向西北和东北2 个方向逐渐递减的特征,降雨侵蚀力在沂蒙山区空间分布上属中等变异,但在县域尺度空间分布上呈弱变异(邹城除外)。Abstract: In order to understand the spatial distribution characteristics of rainfall erosivity in Yimeng Mountain Area, the authors used the ordinary kriging and regression kriging to predict the rainfall erosivity spatial distribution and to analyze the prediction precision and differences of the different interpolation methods, based on the 88 rainfall stations’ daily precipitation data (1980—2010) in Yimeng Mountain Area. The results indicated that, 1) although the spatial distribution regularities of rainfall erosivity in this two methods were coincident, the regression kriging was better for describing the local variabilities. The rainfall erosivity interpolation results of regression kriging are close to the actual calculation values, compared with the ordinary kriging, and the relative prediction accuracy was improved by 53.64%. 2) The maximum value of rainfall erosivity in Yimeng Mountain Area was 5 438.22 MJ·mm/ (hm2·h·a) and the minimum value was 3 033.23 MJ·mm/ (hm2·h·a); the mean value was 4 133.92 MJ·mm/ (hm2·h·a). The analysis of semi variance function showed that the average annual rainfall of flood season and the annual erosive rainfall were the main factors affecting the spatial variability of rainfall erosovity. 3) The spatial distribution pattern of rainfall erosivity in Yimeng Mountain Area decreased gradually from the south to the northwest and from the south to the northeast. The spatial distribution of rainfall erosivity in Yimeng Mountain Area was medium variability, but it was weak variability at county scale (except Zoucheng).