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

目的是在考虑到当地风况、植被和生物结皮的情况下，模拟地球沙丘的形成。这种模拟对我们理解古气候和气候变化下稳定的风成系统的再活化具有重要意义。特别是，在这样的系统中，一种常见的沙丘类型是植被线性沙丘（VLD），但其形成的条件仍然不确定。通过形态动力学模拟，控制VLD的延伸和稳定的过程将被调查的基础上的VLD在Strzelecki沙漠，澳大利亚，和以色列边境附近的例子。这一地区构成了一个很好的边界条件的模型：从VLD在Negev侧的形态过渡到赛夫和新月形沙丘在西奈半岛，人为影响导致植被和地壳的去除，并在最近的风的变化下沙丘再动员。与古气候研究有关的另一种沙丘类型是星星沙丘。这种沙丘出现在多方向风的地区，但其生长和空间分布仍然知之甚少。在本项目中，将采用多尺度模拟方法调查摩洛哥Erg Chebbi的14个星星沙丘的形成历史，并根据沙丘地形、风和沉积物通量的现有数据进行验证。该项目的模拟将有助于阐明尚不清楚的拉伸和堆积沙丘场的形成历史，并改进使用天然固沙剂保护风积土的措施。

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.