基于日降雨量的年均降雨侵蚀力估算模型及其应用——以四川省凉山州为例

摘要

To improve the applicability of Revised Universal Soil Loss Equation (RUSLE) in areas short of rainfall data,such as precipitation,continuous rainfall intensity and raindrops kinetic energy,a new procedure is proposed to estimate the rainfall erosivity factor (R) in mountainous area,southwest China.Soil erosion in Liangshan Yi Autonomous Prefecture in Sichuan of China was selected as an example to be studied using the proposed model.The spatial distribution of soil erosivity across Liangshan Prefecture was analyzed considering land usage and slope of the land employing Geographic information system techniques.The results showed that,soil erosion was less severe in northwest part of Liangshan than in southern and eastern parts,especially in the dry valley sections of such rivers as the Yalong,Heishui and Meigu.Serious soil erosion occurred in farmland with a slope of more than 10.5％ (or 6°).The vegetation coverage may affect the soil erosivity in woodland and grassland.The finding will provide support to the soil and land management in Liangshan in regarding to soil erosion.%为提高连续性降雨强度、降雨量、雨滴动能等数据缺乏地区修正通用土壤侵蚀方程(RUSLE)的计算精度,提出了针对我国西南地区基于日降雨的年均降雨侵蚀力估算模型.进而RUSLE与GIS技术结合,剖析了四川省凉山州的土壤侵蚀空间分布特征.研究表明,四川省凉山州西北部土壤侵蚀较轻,东部和南部侵蚀较高,特别是金沙江干流沿岸、雅砻江下游、黑水河和美姑河等流域侵蚀最为严重.结合土地利用和坡度分析,凉山州＞6.的旱地土壤侵蚀最严重,而林地和草地土壤侵蚀的强弱主要取决于植被覆盖程度.