Aeolian transport over a developing transverse dune
Aeolian transport over a developing transverse dune
复制标题
DOI：
10.1007/s40333-013-0243-2
复制
发表时间：
2014-06
影响因子：
3
通讯作者：
Z. Dong;P. Lv;Zhengcai Zhang;Junfeng Lu
中科院分区：
文献类型：
--
作者：
Z. Dong;P. Lv;Zhengcai Zhang;Junfeng Lu
沙丘上风沙运动的时空变化是控制沙丘形态的基本因素。在本研究中，我们获得了直接的实地观测，风输运在一个发展中的横向沙丘在沙坡头风沙实验场在中国的腾格里沙漠东南部。与平坦表面和与风平衡的沙丘上的关系相比，发展中沙丘上的输送率与风速的关系复杂。我们得到的趋势线运输率在横向沙丘与距离。运输率一般增加，从脚趾到顶部以上的stoss斜坡，但在运输率之间的差异的波峰和脚趾比那些已经提出了更高的沙丘。因此，运输率的波峰/趾比似乎在很大程度上取决于沙丘高度。沙丘上方不同点在不同风速下的通量密度廓线可以很好地用指数衰减律来描述，就像已经提出的跃移通量密度廓线一样。通量密度分布函数中的系数可以根据传输率和风速来定义。然而，相对衰减率随高度和平均跃移高度对风速的依赖性比在风洞中和在平坦表面上观察到的要弱。在这项研究中获得的初步结果需要更多的证据，从实地观察，以充分描述上述发展中的沙丘风沙运输。
The spatial and temporal changes in aeolian transport over a dune are fundamental factors that control the morphology of the dune. In the present study, we obtained direct field observations of aeolian transport over a developing transverse dune at the Shapotou Aeolian Experiment Site in the southeastern part of China’s Tengger Desert. The transport rate versus wind speed relationship is complicated over a developing dune compared with the relationships over flat surfaces and over dunes that are in equilibrium with the wind. We obtained trend lines for transport rate over the transverse dune versus distance. The transport rate generally increased from the toe to the crest above the stoss slope, but the difference in transport rate between the crest and the toe was smaller than those that have been proposed for taller dunes. The crest/toe ratio for transport rates therefore seems to depend greatly on dune height. Flux density profiles for different points above the dune at different wind speeds were well described by the exponential decay law, as has been proposed for saltation flux density profiles. Coefficients in the flux density profile function can be defined in terms of the transport rate and wind speed. However, the dependence of relative decay rate with height and average saltation height on wind speed was weaker than that observed in a wind tunnel and above a flat surface. The preliminary results obtained in this study require more evidence from field observations to fully describe aeolian transport above developing dunes.