腾格里沙漠东南缘反向沙丘形态演化过程

沙丘形态演化是风沙地貌研究的重要内容。反向沙丘是指在相反方向风作用下形成的沙丘，有两个落沙坡，分别对应两个风向，在主风向作用下形成横向沙丘，但在相反方向风作用下，沙丘顶部向主风方向移动，从而形成反向沙丘。反向沙丘存在于任何有两个相反方向风的地区。以腾格里沙漠东南缘平坦沙地上发育的反向沙丘为研究对象，2010年对沙丘迎风坡和背风坡不同部位坡度进行1年期野外测量，旨在阐明反向沙丘的形态演化过程。结果表明：反向沙丘形态演化包括3个阶段：横向沙丘—过渡态—反向沙丘，但研究区的沙丘形态演化经历5个阶段：横向沙丘—过渡态—反向沙丘—过渡态—横向沙丘。不同演化阶段的沙丘迎风坡和背风坡角度发生明显变化。该研究结果增加人们对反向沙丘形态演化过程的认识，对区域风沙地貌改造利用提供理论依据。

The Reversing Dune Geomorphology Development Process in the Southeast Tengger Desert

Dune geomorphology is one of important issues in aeolian geomorphology. Reversing dune has two leeward slopes, and forms under two reversed wind directions. There are transverse dunes formed under primary wind direction, and the dune crest moves to primary wind direction under reversed wind direction. The reversing dunes can form under anywhere there are reversed wind directions. In this paper, the developing reversing dune on a flatted shifting surface in the southeast Tengger Desert were selected to study the dune geomorphology development processes. The windward slope and leeward slope were measured in the field conditions. The result indicated that the reversing dune development can divided into three stages:transverse dune, transition and reversing dunes. During the different development stages, the windward slope and leeward slope obviously changed.