沙漠公路防护林不同林带位置的风沙流结构

利用BSNE集沙仪对沙漠公路两侧防护林的近地表风沙流结构进行研究,结果表明:(1)随着高度的增加,不同林带位置上部的输沙量趋于一致,各点风沙流输沙量差异主要集中在近地表处,而植被覆盖与否对近地表气流中的输沙量有决定性作用,输沙量表现为:迎风面流沙地林带间背风面林带内。(2)迎风面及流沙地风沙流输沙量主要分布在距地表20 cm高度内,背风面则集中分布在50 cm高度内,均占观测高度输沙总量的74%以上,林带间及林带内风沙流输沙量在各高度层分布较为平均,介于11%~23%之间。(3)护林体系外(迎风面、背风面及流沙地),风沙流输沙垂直分布差异很大,输沙量随高度增加呈幂函数形式降低,而防护林体系内(林带间及林带内),风沙流垂直分布差异趋于减小,输沙量随高度增加呈多项式形式先降低后增加。

Aeolian-Sand Flow Structure at Different Locations along Desert Highway Shelterbelt

In this paper, BSNE sampler was used to study Aeolian-sand flow structure in ground layer along both shelterbelt sides of a desert highway.The results are as follows:① The Aeolian-sand flux at the upper part of shelterbelt trended to accordance with the increase of height at different positions of shelterbelt.The difference of Aeolian sand flux at different observation sites occurred mainly in the ground layer.Vegetation and its coverage had a decisive effect on Aeolian-sand flux in the ground layer.Aeolian-sand flux along the shelterbelt was in an order of windward side ＞ quicksand land ＞ inter-shelterbelt zone ＞ leeward side ＞ shelterbelt;② The Aeolian-sand flux on windward side of the shelterbelt and quicksand land was mainly distributed within 20 cm height from the ground surface,and that on leeward side of the shelterbelt was mainly distributed within 50 cm height,which accounted for over 74％ of the total Aeolian-sand flux within the observation height.The Aeolian-sand flux in the inter-shelterbelt zone and the shelterbelt was relatively uniform and varied in a range of 11％-23％;③ The difference of vertical distribution of Aeolian-sand flux outside of the shelterbelt windward side, leeward side and quicksand land was very high,the Aeolian-sand flux was decreased with the increase of height in a power-function way, but it was in a decrease trend in the shelterbelt, and the Aeolian-sand flux was decreased at first and then increased with the increase of height in a polynomial-function way.