毛乌素沙地不同固沙措施下沙丘的移动特征

Barchan dunes movement of different sand fixation measures in Mu Us sandy land

【目的】研究不同固沙措施下沙丘的治理效果及移动特征.【方法】以Google Earth平台高分辨率遥感影像为基础,选择毛乌素沙地中未经过固沙措施、沿迎风坡进行单圈植被固定、沿迎风坡进行多圈植被固定和生物与非生物沙障相结合的四种固沙措施条件下的新月形沙丘共70座,通过影像测量,并结合研究区风况资料,分析了2002-2010年,不同固沙措施下的新月形沙丘移动的性质、强度以及沙丘移动与高度的变化规律.【结果】研究区起沙风主风向为偏西北风,频率66.4%,受此影响,沙丘向偏东南方向移动;由于植被增加了沙丘表面粗糙度,四种不同类型沙丘的年平均移动速度分别为:流动沙丘(5.4m/a)>单圈植被固定沙丘(4.1m/a)>多圈植被固定沙丘(1.8m/a)>生物与非生物结合固定沙丘(1.0m/a).【结论】随着植被的增加,沙丘移动速度减慢.

[Objective] In order to study the effect and movement characteristics of sand dunes move- ment under different sand fixation measures. [Method] This text was based on QuickBird high resolution image, select 70 typical barchan dunes in Mu Us Sandy Land, and divided into four types： mobile dune, fixed sand dune with one circle natural vegetation, fixed sand dune with multi circle natural vegetation, fixed sand dune with biological and abiotic sand barriers,combined with image measurement and wind re- gime data, Analyzed the character, speed of dune movement from 2002 to 2010 and the change regulation of dune movement and height variation. [Result] The investigated area influenced by northwesterly wind, which frequency of 66.4%, the moving direction of sand dunes in study area was southeast. Due to the veg- etation increased the dune surface roughness, at the same height, the average speed for the four different types of dunes was,mobile dune （5.4 m/a）〉fixed sand dune with one circle natural vegetation （4. 1 m/a） 〉fixed sand dune with multi circle natural vegetation （1.8 m/a）〉fixed sand dune with biological and abi- otic sand barriers （1.0 m/a）. Height and movement speed of mobile dune and fixed sand dune with one cir- cle natural vegetation had extremely significant negative correlation. [Conclusion] With the increase of veg- etation, the movement of the dunes slowed down.