西藏冻融侵蚀空间分布规律

Spatial Distribution Characteristics of Freeze-Thaw Erosion in Tibet

西藏是我国冻融侵蚀最主要的分布区,也是受冻融侵蚀危害最为严重的区域。以影响冻融侵蚀主要因子为指标所建立的评价模型对西藏冻融侵蚀进行分级评价所得出的结果为依据,分析了西藏冻融侵蚀的空间分布规律。分析结果表明:(1)西藏冻融侵蚀分布范围广大,冻融侵蚀总面积达664 317.4 km2,占该区国土面积的55.3%;(2)西藏冻融侵蚀的区域分异明显,不仅不同强度冻融侵蚀具有不同的区域分布特征,而且冻融侵蚀地区分布差异明显,每个地区都有不同于其他地区的冻融侵蚀空间分布特点;(3)西藏冻融侵蚀垂直分异明显,不同强度冻融侵蚀的百分比构成随海拔高度的升高而呈现有规律的变化,冻融侵蚀在垂向上的分布具有在海拔较低区域和较高区域分布面积小、强度大,中间区域分布面积大、侵蚀强度小的特点。

Tibet is the main distribution area of freeze-thaw erosion and the most serious damaged region by freeze-thaw erosion in China.In order to prevent and control the occurrence and development of the freeze-thaw erosion effectively,it is necessary to understand the present situation and spatial distribution characteristics of freeze-thaw erosion in Tibet.Based on the classification and assessment results of the freeze-thaw erosion,this paper comprehensively discussed the spatial distribution characteristics of freeze-thaw erosion in Tibet.The results show：（1） The distribution of freeze-thaw erosion is very extensive in Tibet,freeze-thaw erosion area is 664 317.4 km2,accounting for 55.3% of the total local land area.（2） The regional differentiation of freeze-thaw erosion is obvious.Not only the different intensity freeze-thaw erosion has the different regional distribution characteristics,but also the difference of the freeze-thaw erosion distribution in different region is also obvious,each region has its own spatial distribution characteristic,which is different with other regions.（3） The vertical differentiation of freeze-thaw erosion is also obvious in Tibet.The percentage constitutes of different intensity freeze-thaw erosion orderly change along with altitude,and the freeze-thaw erosion area is small and the intensity is heavy in high elevation region and low elevation region,and the freeze-thaw erosion area is large and the intensity is slight in middle elevation region.