The influence of hillslope processes on large-scale landform evolution

在过去的几十年里，地貌演化模拟不仅在地貌学方面受到了越来越多的关注，而且在构造和气候变化的背景下也受到了越来越多的关注。目前这一领域的研究大多涉及大规模河流侵蚀，所建立的微分方程并不是很复杂，并且已经有了有效的数值实现。尽管坡面过程对气候和植被变化的敏感性可能比河流侵蚀的敏感性更高，但在数值模型中处理坡面过程的情况并不多见。特别是，山坡过程和河流侵蚀之间的相互作用显然只在少数几项研究中得到了解决。河流侵蚀是山坡过程的主要长期驱动因素。反过来，泥沙从山坡输送到河流带来了强烈的反馈。虽然山坡过程总体上减少了地形起伏，但这种反馈增加了平衡抬升所需的河流的陡度，因此甚至可能增加大范围的地形起伏。该项目试图量化山坡过程和河流侵蚀之间的相互作用，重点放在大规模的地貌演变上。不同的建模方法，从最简单的线性扩散方程到统计的、基于事件的滑坡模型都将被实施和研究。除了量化这些过程的影响外，重点将放在如何通过分析实际地形来评估不同模型在给定条件下的适用性以及如何估计各自的模型参数的问题。

Landform evolution modeling has received growing interest not only in geomorphology over the last decades, but also in the context of tectonics and climate change. Most of the contemporary studies in this field refer to large-scale fluvial erosion where the established differential equations are not very complicated, and efficient numerical implementations have become available. In contrast, processes at the hillslope scale are more complex, and there is little consensus about appropriate modeling approaches.Although the susceptibility of hillslope processes to changes in climate and vegetation may be even higher than that of fluvial erosion, hillslope processes have been addressed in numerical models not very often. In particular, the interaction between hillslope processes and fluvial erosion has apparently been addressed only in a few studies. Fluvial erosion is a major long-term driver of hillslope processes. In turn, the delivery of sediments from the hillslopes to the rivers introduces a strong feedback. While hillslope processes in general reduce relief, this feedback increases the steepness of the rivers required for balancing uplift and may thus even increase the large-scale relief.The project attempts to quantify the interaction between hillslope processes and fluvial erosion with focus on large-scale landform evolution. Different modeling approaches ranging from the simplest linear diffusion equation to statistical, event-based landslide models will be implemented and investigated. Beyond quantifying the effect of these processes, focus will be on the question how the applicability of the different models under given conditions can be assessed by analyzing real topographies, and how the respective model parameters can be estimated.