Regional Soil Erosion Terrain Factor Analysis And Retrieval Research

Analysis and Extraction of Topographic Factor in Regional Soil and Water LossLiu Xinhua(Directed by Li Rui)AbstractTopography is one of factors affecting soil and water loss. Selection, extraction and analysis of multi scale topographic factor is an radical issue in assessment of regional soil and water loss, which is an important portion in macro assessment and analysis of regional soil and water loss project.Based on analysis of China soil loss and its landform characters, multi scale topographic index are developed and extracted. A gradient correction downscaling model is initially made and applicability of relief index in macro scale is analyzed. The main results are:1.Based on the research in assessment of soil and water loss and geomorphology in home and abroad, according to the characters of china soil loss and landform environment, multi scale topographic index in assessment of soil loss are developed. Gradient is main index in micro scale. Relief, roughness and variance coefficient in elevation are main index in macro scale.2.Using multi scale DEM datum, multi scale topographic index are extracted and mapped in the whole country and sample area in bess plateau, which prepare topographic datum basis for developing regional soil and water loss assessment model.3.Based on overlay and analysis function in GIS, a gradient correction downscaling model in yanr gully is made, which apply an effective method for sealing-up in multi scale.4.Using long-term average sediment transport modulus in china, applicability of relief is initially analyzed and assessed, which establish a foundation for study the quantitative relation between topographic factor and soil erosion. Initial results indicate relief is the best topographic factor in assessment of regional soil and water loss.