Regional Soil Erosion Assessment With Remote Sensing And Geography Information System

Soil erosion has become the worldwide serious environment problem, threatening the human sustainable development. Soil erosion concerns multi factors, multi spatial and temporal scales. Remote sensing techniques have the ability to monitor the earth surface physical processes and detect the changes. The geography information system can play an important role in analysis and decision-making. On the regional level, this paper discusses the application purpose and the main parts of soil erosion monitoring and assessment. And this paper studies some methods of remote sensing and GIS applied to regional soil erosion monitoring and assessment.The main conclusions are as following:(1 ) Discussing the theoretical problem of soil erosion monitoring and assessment on regional scaleThis paper summarizes the studies of soil erosion assessment on regional scale to three categories depending on temporal scales. Those are soil erosion actual status survey and assessment on regional scale, regional dynamic change analysis of soil erosion status, and situation simulation. Soil erosion actual status survey and assessment on regional scale also can be divided into soil erosion risk ranking and soil loss quantitive assessment.Through the time scale, connotation and destination, this paper distinguishes the soil erosion risk ranking and erosion rate quantitative assessment, the two components of soil erosion status investigation. And it is considered that the soil erosion risk ranking is the main means suitable to support regional resources management.(2) Using three methods to assess the same area of Miyun Reservoir and Compareing the results obtained by these methods based on pixel to analysis the reason of differenceAmong these factors that influent the process of water and soil erosion, vegetation cover and slope steepness are selected. The vegetation cover data in the Upper Basin of Miyun Reservoir have been estimated from normalized difference vegetation index derived from Landsat-7 ETM+ images. Based on the pixels of DEM slope steepness is computed. Vegetation cover and topographic factor can be combined as a crosstab model. A soil erosion risk map with six grades can be drawn. Using the method the probability and the extent of soil loss can be measured.The annual soil loss is estimated with a modified version of the Universal Soil Loss Equation (USLE). All the data necessary for model factors estimation are collected between 2001 and 2002...