Investigating parabolic and nebkha dune formation using a cellular automaton modelling approach
Investigating parabolic and nebkha dune formation using a cellular automaton modelling approach
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DOI：
10.1002/esp.1571
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发表时间：
2008-04
影响因子：
3.3
通讯作者：
J. Nield;A. Baas
中科院分区：
文献类型：
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作者：
J. Nield;A. Baas
在沿海和半干旱生态地貌相互作用复杂且不能很好量化的环境中，植被对风沙丘陵景观的形态塑造起着重要作用。我们提出了一个离散的生态地貌风沙景观模型(DECAL)，能够模拟看起来逼真的植被沙丘形状，允许在不同的时间和空间尺度上探索生态和形态过程之间的关系。细胞自动机算法应用了三个简单的规则，导致了复杂沙丘环境的自组织，包括具有独特沉积尾巴的nebkha，它与梅斯基特类型的灌木形成联系，以及发夹(长壁)抛物线沙丘，它具有尾脊，它是从与植被演替相关的井喷演变而来的。改变模拟的条件会产生不同的景观，这些景观与真实世界的沙丘观测结果定性一致。该模型模拟了地形对泥沙供应、植被分布、密度和生长特征以及初始扰动变化的响应。将植被引入到模型中，将空间和时间尺度联系在一起，以前在裸沙细胞自动机中是无量纲的。网格分辨率比建模的植被元素的代表性大小粗略，产生相似的形态，但当单元大小缩小到更小的维度时，所产生的景观演变显著不同。模型进一步表明，多种植被类型的相对响应特征及其与地貌过程的相互反馈对景观平衡有显著影响，表明在风沙环境中，植被产生了一个特征的长度尺度。这个简单的植被沙丘模型展示了细胞自动机方法在探索复杂地球表面系统中生态和地貌之间相互作用的影响方面的能力和多功能性。版权所有©2007 John Wiley&Sons，Ltd.
Vegetation plays an important role in shaping the morphology of aeolian dune landscapes in coastal and semi‐arid environments, where ecogeomorphic interactions are complex and not well quantified. We present a Discrete ECogeomorphic Aeolian Landscape model (DECAL) capable of simulating realistic looking vegetated dune forms, permitting exploration of relationships between ecological and morphological processes at different temporal and spatial scales. The cellular automaton algorithm applies three simple rules that lead to self‐organization of complex dune environments, including nebkhas with distinctive deposition tails that form in association with mesquite‐type shrubs, and hairpin (long‐walled) parabolic dunes with trailing ridges that evolve from blowouts in association with vegetation succession. Changing the conditions of simulations produces differing landscapes that conform qualitatively to observations of real‐world dunes. The model mimics the response of the morphology to changes in sediment supply, vegetation distribution, density and growth characteristics, as well as initial disturbances. The introduction of vegetation into the model links spatial and temporal scales, previously dimensionless in bare‐sand cellular automata. Grid resolutions coarser than the representative size of the modelled vegetation elements yield similar morphologies, but when cell size is reduced to much smaller dimensions, the resultant landscape evolution is dramatically different. The model furthermore demonstrates that the relative response characteristics of the multiple vegetation types and their mutual feedback with geomorphological processes impart a significant influence on landscape equilibria, suggesting that vegetation induces a characteristic length scale in aeolian environments. This simple vegetated dune model illustrates the power and versatility of a cellular automaton approach for exploring the effects of interactions between ecology and geomorphology in complex earth surface systems. Copyright © 2007 John Wiley & Sons, Ltd.