Model for dune morphodynamics under consideration of multidirectional winds, vegetation and biogenic crusts

其目的是在考虑到当地的风向、植被和生物结壳的情况下，对地球沙丘区域的形成进行建模。这种模式对我们理解古气候以及在气候变化下稳定的风沙系统的再动员都有影响。特别是，在这种系统中，一种常见的沙丘类型是植被线性沙丘(VLD)，但其形成条件仍然不确定。通过形态动力学建模，以澳大利亚斯特泽莱基沙漠和埃及-以色列边界附近的VLD为例，研究控制VLD伸长和稳定化的过程。这一区域为模式提供了一个很好的边界条件：从内盖夫一侧的VLD到西奈半岛的Seif和Barchan沙丘的形态过渡，在那里，人为影响导致植被和结壳的移除，以及在最近的风变化下沙丘的再动员。另一种与古气候研究相关的沙丘类型是星形沙丘。这种沙丘出现在多向风的地区，但对其生长和空间分布仍知之甚少。在本项目中，将采用多尺度模拟方法调查摩洛哥Erg Chebbi的14个恒星沙丘的形成历史，并根据沙丘地形、风和泥沙通量的现有数据进行验证。该项目的模拟将有助于阐明目前仍鲜为人知的沙丘地拉长和堆积的形成历史，并改进使用天然固沙剂保护风沙土的措施。

The aim is to model the formation of the Earth’s dune fields under consideration of local wind regimes, vegetation and biogenic crusts. This modeling has impact on our understanding of paleoclimate and the remobilization of stabilized aeolian systems under climate change. In particular, one common type of dune in such systems is the vegetated linear dune (VLD), but the conditions for its formation are still uncertain. By means of morphodynamic modeling, the processes controlling VLD elongation and stabilization shall be investigated based on the examples of the VLDs in Strzelecki Desert, Australia, and near the Egypt-Israel border. This area poses one excellent boundary condition for the model: the morphologic transition from VLD at the Negev side to seif and barchan dunes in Sinai, where anthropogenic influences led to removal of vegetation and crusts, and to dune remobilization under recent wind changes. One further type of dune relevant for the investigation of paleoclimate is the star dune. This dune occurs in areas of multidirectional winds, but their growth and spatial distribution are still poorly understood. In this project, a multiscale modeling approach shall be applied to investigate the formation history of the 14 star dunes of Erg Chebbi, Morocco, and validated based on available data on dune topography, wind and sediment flux. The simulations of this project shall help to elucidate the still poorly understood formation history of elongating and accumulating dune fields, and to improve measures of aeolian soil protection with natural sand stabilizers.