雅鲁藏布江源区土壤侵蚀特征

    Soil Erosion in the Source Area of the Yarlung Zangbo in China

    • 摘要: 以雅鲁藏布江源区所在的马泉河流域为研究区域,运用遥感和GIS技术对土壤侵蚀及其空间分布的地貌特征进行研究,结果表明:轻度及其以上强度土壤侵蚀面积为18 933.33 km2 ,占源区面积的71.86%;冻融侵蚀是土壤侵蚀的主要形式,占源区面积的82.53%;风力侵蚀占5.33% ,集中分布在河谷宽谷段;水力侵蚀面积所占比例较小,以微度侵蚀为主。土壤侵蚀的地理分布规律受海拔高度的影响较大,垂直分异明显,主要发生在坡度等级较低、地势较平坦的地区。轻度以上冻融侵蚀主要分布在海拔4 600~5 200 m,且有20%以上集中在0°~5°坡地;风力侵蚀主要分布在海拔4 600~5 600 m、0°~25°坡地。极强烈风力侵蚀以西南坡向最大,南、西、东南坡和平地分布较少。强烈风力侵蚀以平地所占比例最大,东北和西2个坡向次之。坡向对冻融侵蚀影响较小。

       

      Abstract: Soil erosion and geomorphological characteristics of its spatial distribution in the Maquan River basin, which was taken as a case for study of the Yarlung Zangbo River source area, were studied, with remote sensing and GIS technologies. Results show that the area under soil erosion above light is 18 933.33 km2 , accounting for 71.86% of the total source area; freeze-thaw erosion is the major form of soil erosion, accounting for 82.53%; wind erosion occurs only in wide sections of the river valley, accounting for 5.33%; and water erosion, often mild in intensity, is small in area. Geographical distribution of the soil erosion is highly influenced by altitude with significant vertical differentiation. Soil erosion is mainly distributed in areas relatively low in slope or flat in topography. Extremely strongwind erosion occursmainly on slopes facing southwest, and quite little on slopes facing south, west and south-east and in flatland, while strongwind erosion mostly in flatland, and some on slopes facing northeast and west. Aspect of a slope does not affect much on freezethaw erosion.

       

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