降雨侵蚀力作为评价降雨对土壤侵蚀能力的关键指标,对于确定土壤可蚀性以及预防水土流失、制定水土保持规划与决策具有重要的理论意义.本文选取陕南地区及其周边地区共22个气象站1960-2014年连续55年日降雨量数据,利用逐日降雨量估算侵蚀力模型计算陕南地区降雨侵蚀力;在ArcGIS10平台下,采用反距离权重空间插值的方法,绘制陕南地区降雨侵蚀力空间分布图,分析全年及其季节空间分布特征;利用Mann-Kendall趋势分析法、气候趋向率和变异系数分析降雨侵蚀力年内和年际变化特征.结果表明:(1)陕南地区多年平均年降雨侵蚀力空间分布与年侵蚀性降雨量空间分布具有相似性,都是由北向南逐渐增加.(2)陕南地区多年平均年降雨侵蚀力为3 872MJ· mm·hm-2 ·h-1 ·a-1,年内分布差异较大,主要集中于6-9月,冬季变异系数最大.安康站点夏季降雨侵蚀力上升趋势通过了0.01显著性检验.(3)降雨侵蚀力年际变异系数达到0.30,80年代降雨侵蚀力最大.略阳站点年降雨侵蚀力呈下降趋势,汉中站点基本不变.%As an indicator of soil erosion,rainfall erosivity is significant for its role in developing soil erosion prediction as well as prevention strategies,and it plays an important role in decision making for soil and water conservation.For the period of 1960-2014,values of rainfall erosivity was collected at 22 meteorological stations located in the southern region of Shaanxi and its surrounding areas and then they were analyzed on a daily basis.A rainfall erosivity spatial distribution map was drawn and the annual and seasonal distribution characteristics was analyzed using the inverse distance weighted interpolation method under the platform of ArcGIS 10.The methods of Mann Kendall climatic trend analysis was used to interpret the characteristics of annual or interannual rainfall erosivity.The results show that:1) The spatial distribution characteristics of average annual rainfall erosivity in the south of Shaanxi Province were similar to that of annual erosive rainfall,with an increasing trend from the north to the south;2) the value for the annual average rainfall erosivity in southern Shaanxi was 3872 MJ · mm · hm-2 · h-1 -1a.Its seasonal distribution was uneven,concentrating from June to September.The maximum variation coefficient occurs in the winter.The summer rainfall erosivity of Ankang station climbed up through the 0.01 significant test;3) the variation coefficient of annual rainfall erosivity was 0.30,and the rainfall erosivity reached its maximum in the 1980s.Lueyang station expressed a downward trend,and Hanzhoung stays mainly unchanged.
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