雅鲁藏布江曲水-乃东段沙化空间特征研究

Spatial feature of desertification in Qushui-Naidong area of Yarlung Zangbo River

雅鲁藏布江曲水-乃东段地处"一江两河"核心区域,土地沙化对区域经济发展和生态安全造成重大影响。通过收集多源数据,采用RS、GIS和数理统计方法,研究沙化分布特点及驱动机理。结果表明:沙地分布呈现北重南轻、西重东轻的格局,总面积621km2,占全区面积15%;沙化从轻度到极重度的面积大致呈现正态分布,极重度沙地面积95km2,占沙地总面积的15%;重度沙地153km2,占25%;中度沙地314km2,占51%;轻度沙地58km2,占9%;近东西向断层破碎带成为沙地发育和发展主体;海拔≤4200m的沙地占沙地总面积98%,坡度≤15°的沙地占沙地总面积85%,平地及全阳坡沙地占沙地总面积的77%;极重度沙地的沟壑密度平均值达659m/km2;近年来,雅鲁藏布江北岸及拉萨河东岸沙化大致维持扩散态势,与之隔河而望的区域因工程防治,沙化面积收缩。

The Qushui-Naidong area is located in the main region of watershed of the Yarlung Zangbo River,the Lhasa River,and the Nyang Qu River,and desertification there has been making a significant impact on regional economic development and ecological security.By collecting multi-source data,and using remote sensing and geographic information system technology,desertification distribution feature and driving mechanism were studied.The results showed that the desertification area accounted for 15% of the total area is about 621 km2,its distribution pattern is severe in northern and light in southern,severe in western and light in eastern;The area from light desertification to extremely severe desertification generally expresses as a normal distribution,the extremely severe desertification area accounted for 15% of the total desertification area is about 95km2;The severe area is about 153 km2 which accounts for 25% of the total desertification area;The medium area is about 314 km2 which accounts for 51%;the light is about 58 km2 which accounts for 9%;The nearly east-west fault fracture zone is the main region of desertification development and growth;The sand land its altitude ≤4200m accounts for 98% of the total,the sand land its slope ≤15° accounts for 85%,and the flat and full sunny sand accounts for 77%;The average gully density in the extremely severe desertification area is 659m/km2;In recent years,the desertification in the north bank of Yarlung Zangbo River and the east bank of the Lhasa River generally kept spread situation,but the desertification area of the other banks has been reducing because of project prevention.