利用长江上游135个国家基准气象站1960-2009年的日降雨量统计得到的多年平均降水量,并对这些气象站的多年平均降雨量和该地区225个县多年平均降雨量数据进行空间分析处理,结合USLE模型计算得到长江上游土壤水蚀分布图,利用GIS技术手段对不同降雨带下的土壤水蚀状况进行了分析。研究表明:该区域水蚀量占土壤侵蚀总量的78%;水蚀程度分布与降雨带分布均呈自西向东递增趋势,局部存在差异。江源区及川西北部,多年平均降雨量小于900 mm,水蚀以微度为主;川中部地区降雨分布不均,水蚀区域差异较大;四川盆地与陕、甘交界地段,降雨等级在4-5之间、重庆北部降雨等级在7-8之间的地区,水蚀均较为严重,以强度以上为主;云南西北金沙江下游地区、重庆西南以及湖北秭归、宜昌等地降雨等级在7-8之间,水蚀以中、强度为主;当降雨等级为8时,土壤侵蚀指数达最大(160.5)。该结果与2000年长江上游土壤侵蚀遥感调查结果基本一致,为进一步揭示长江上游水土流失的空间分布及成因提供参考。

Based on daily rainfall data recorded by 135 meteorological stations from 1961 to 2009 and multi-year average precipitation data of 225 counties in the Upper Yangtze River Basin,combined with water erosion distribution map calculated by USLE model,the relationship between precipitation and water erosion in the Upper Yangtze River Basin was analyzed through using the spatial analysis function on GIS software.The results show that water erosion accounts for 78% of the whole soil erosion; for the distribution of water erosion and precipitation,although there is significant difference in local area,they are all increasing from west to east.The source region and northwest of Sichuan,where multi-year average precipitation is less than 900 mm,occurs micro-degree water erosion mainly.In central Sichuan,just as uneven precipitation distribution,water erosion is uneven.In the junction of Sichuan and Shaanxi,Sichuan and Gansu,where precipitation grade is 4 to 5 and north of Chongqing where precipitation grade is 7 to 8,water erosion is serious,intensity erosion occurs mainly; middle intensity erosion dominates the region of the northwest of Yunnan,southwest of Chongqing and Yichang of Hubei,where precipitation grade is 7 to 8.The soil erosion index reaches the maximum value (160.5)in precipitation grade 8.This result is close to 2000 Remote Sensing interpretation of soil erosion,revealing the soil erosion distribution features and causes under different precipitation condition in the Upper Yangtze River