基于GIS和USLE的汶川地震后理县土壤侵蚀特征及分析

为了较准确地评估汶川地震后理县的土壤侵蚀状况,该研究结合GIS、RS、USLE(universal soil loss equation)定量地分析了汶川地震灾区理县的潜在土壤侵蚀和实际土壤侵蚀状况,并对地震前后土壤侵蚀量做了简要的对比分析,并且从坡度、坡向、土地利用类型、高程4个方面系统地研究了不同侵蚀强度区的面积和土壤侵蚀量的变化。研究结果表明:震后理县全年土壤侵蚀量达844.46万t/a,平均侵蚀量为1957.79t/(km2·a),属于轻度侵蚀,相比地震前轻度侵蚀、强度侵蚀、极强度侵蚀区域面积都有很大增长,有林地、坡度≥30°～50°、海拔≥2000～3000m、坡向为南坡、西坡的地带土壤侵蚀比较严重。该研究为理县震后土壤侵蚀的预防和治理工作提供了很好的依据。

Characteristics and analysis of soil erosion in Li country after Wenchuan earthquake based on GIS and USLE

In order to more accurately evaluate soil erosion of Li country, Wenchuan earthquake-stricken area, Sichuan province, potential and actual soil erosion was qualitatively analyzed using the combination method of GIS, RS and USLE, and a brief comparison of soil erosion before and after earthquake was conducted. Moreover, changes of soil erosion area about different erosion intensity and the soil erosion amount were studied from four aspects, including slope, slope aspect, land use patterns and elevation. The results showed that soil erosion in Li country amounted to 844.46 million tons in the whole year and the average soil erosion was 1957.79 t/(km2·a), belonging to the moderate erosion. Compared with before earthquake, the areas of soil erosion were enlarged in mild, intensive and extreme regions especially at the region with slope more than 30-50 degree, altitude more than 2000-3000 m, as well as aspect of south and west slope. Further, the results provide a better basis for the reconstruction and the conservation of the soil erosion in Li country.