Study On Quatitative Mornitoring Of Soil Erosion: Rainfall Erosivity Factor

Soil erosion is the process of that soil particles with surface attachments are moved, transferred and deposited under external forces, such as water power, gravity and wind power, physical, chemical weathering and eluviations, including human beings activities. Soil erosion has brought some problems such as land degradation, sedimentation and water pollution, which is one of the most serious environmental problems in the world.Soil erosion is very serious in China. The erosion area is about one third of the area of the country. About 5—10 billion tons of silt flows into rivers and lakes annually, especially in the up-middle parts of Yellow River and Yangtse River basins. Chinese government has being made great efforts on soil erosion controlling. Because of low vegetable coverage and intensive human activities, serious soil erosion also takes place in the upstream part of Huaihe River basin. Quantitative monitoring and assessment of soil erosion conditions is necessary.USLE is most widely used as an effective tool of monitoring and assessment of soil erosion after being proposed in 1965. Six factors, i.e rainfall erosivity (R factor), soil erodibility (K factor), topographic factor (LS factor), coverage factor (C) and supporting management factor (P factor), are defined as quantitative factors to describe how much effect of these on soil losses. Rainfall erosivity (R factor) is used as a comprehensive index to reflect climate effect on soil erosion. In USLE, it is generally expressed in terms of rainfall energy (E) and the max 30min rain intensity (I₃₀), both of which determined their potential to cause erosion. There are many researches on calculation of R, including the classical algorithm and his successors. Many simplized models of R have been proposed, which enables USLE apply to local regions with better availability and higher precision.Based on the Remote Sensing Quantitative Monitoring model (RSQM model) derived of USLE, an attempt will be given on region erosion monitoring in the Huaihe...