定量遥感支持下的红壤丘陵区土壤侵蚀敏感性评价——以长沙市为例

定量遥感技术的发展为研究区域生态环境敏感性提供了有效的手段.针对红壤丘陵区这一典型的脆弱生态系统,在遥感和地理信息系统的支持下,建立了红壤丘陵区土壤侵蚀敏感性评价信息系统.根据RUSLE方程中的4个自然条件因子对土壤侵蚀敏感性的影响,建立红壤丘陵区土壤侵蚀敏感性定量评价指标体系,并对长沙这一典型红壤丘陵区的土壤侵蚀敏感性进行评价.通过解译Lan出at TM/ETM 影像数据获得长沙市土壤侵蚀敏感性评价的K因子、C因子分布图;利用ARCGIS数字化和空间分析得到R因子以及地形起伏度分布(LS因子).通过主成分分析法确定各评价因子的权重;最后通过加权叠加法获得长沙市土壤敏感性评价结果.研究结果表明,高度敏感以上面积2618km2,占全市面积的20.3%,中度敏感面积4404km2,占全市面积的37.2%,轻度以下敏感面积5073km2,占全市面积的42.5%,这说明长沙市土壤侵蚀敏感性较高.

Soil Erosion Sensitivity Evaluation of Hilly Region of Red Soil Based on Quantitative Remote Sensing - a Case Study in Changsha City

The development of remote sense(RS) and geographic information system(GIS) provides an effective means for studying sensitivity of regional vulnerable ecology and environment.Aiming at the hilly region of red soil with vulnerable ecosystems and supported by the RS and GIS,this study establishes a soil erosion sensitivity evaluation information system database for hilly region of red soil.The quantitative indicates system for soil erosion sensitivity evaluation has been established,guided by four natural factors in the Revised Universal Soil Loss Equation(RUSLE) which are rainfall erosivity factor,soil erodibility factor,slop length and gradient factor,crop factor.the soil erosion sensitivity of a typical area in this region,i.e.,Changsha city is evaluated.The K factor and C factor values used for Changsha soil erosion sensitivity evaluation are obtained by interpreting Landsat TM/ETM+ image data,the R factor map and relief map(LS factor) are obtained by Digitizing and space analyzes in GIS;the weights of factors for evaluation are decided by PCA(Principal Component Analysis);the result of soil erosion sensitivity evaluation of Changsha is calculated by Multi-factor superposing with weight.The results showed that 20.3 percent of the total land(approximately 2618km2) are maintaining at high or extremity sensitivity,moderate sensitivity,42.5 percent of the total land(approximately 5073km2) are maintaining at mild or none sensitivity;it concludes that entire soil erosion sensitivity of Changsha city is high.The space distributing of all classificatory soil erosion sensitivity evaluation of Changsha is analysized.Reasons of soil erosion sensitivity are analysized from two points view which are relief and vegetation fraction.