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Connecteur WG Think‐Tank Team Jo?o Pedro Nunes John Wainwright Charles L. Bielders Frédéric Darboux Peter Fiener David Finger Laura Turnbull 《地球表面变化过程与地形》2018,43(6):1355-1360
Water‐ and sediment‐transfer models are commonly used to explain or predict patterns in the landscape at scales different from those at which observations are available. These patterns are often the result of emergent properties that occur because processes of water and sediment transfer are connected in different ways. Recent advances in geomorphology suggest that it is important to consider, at a specific spatio‐temporal scale, the structural connectivity of system properties that control processes, and the functional connectivity resulting from the way those processes operate and evolve through time. We argue that a more careful consideration of how structural and functional connectivity are represented in models should lead to more robust models that are appropriate for the scale of application and provide results that can be upscaled. This approach is necessary because, notwithstanding the significant advances in computer power in recent years, many geomorphic models are still unable to represent the landscape in sufficient detail to allow all connectivity to emerge. It is important to go beyond the simple representation of structural connectivity elements and allow the dynamics of processes to be represented, for example by using a connectivity function. This commentary aims to show how a better representation of connectivity in models can be achieved, by considering the sorts of landscape features present, and whether these features can be represented explicitly in the model spatial structure, or must be represented implicitly at the subgrid scale. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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Numerical models are used to examine the effects of porphyroblast growth on the rheology of compositionally layered rocks (metapelites and metapsammites) and by extension the middle crust during prograde metamorphism. As porphyroblast abundance increases during prograde metamorphism, metapelitic layers will strengthen relative to porphyroblast‐free metapelitic units, and potentially relative to quartzofeldspathic metapsammitic units. As metapelitic layers become stronger, the integrated strength of compositionally layered successions increases, potentially causing large volumes of mid‐crustal rock to strengthen, altering the strain‐rate distribution in the middle crust and affecting the geodynamic evolution of an orogenic belt. The growth of effectively rigid porphyroblasts creates strength heterogeneities in the layer undergoing porphyroblast growth, which leads to complex strain‐rate distributions within the layer. At the orogen scale, the strengthening of large crustal volumes (on the order of thousands of cubic kilometres) changes the strain‐rate distribution, which may change exhumation rates of high‐grade metamorphic rocks, the geothermal structure and the topography of the orogen. The presence of a strong zone in the middle crust causes strain‐rate partitioning around the zone, suppressed uplift rates within and above the zone and leads to the development of a basin on the surface. 相似文献
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