A transport‐distance approach to scaling erosion rates: 2. sensitivity and evaluation of Mahleran
A transport‐distance approach to scaling erosion rates: 2. sensitivity and evaluation of Mahleran
复制标题
缩放侵蚀率的传输距离方法：2. Mahleran 的灵敏度和评估
DOI：
10.1002/esp.1623
复制
发表时间：
2008
影响因子：
3.3
通讯作者：
Bantigegne Fenti
中科院分区：
文献类型：
--
作者：
J. Wainwright;A. Parsons;E. Müller;R. Brazier;D. M. Powell;Bantigegne Fenti
在本系列的第一篇论文中，我们证明了大多数基于过程的侵蚀模型都有一系列内置的假设，这导致我们质疑其真正的过程基础。在本系列的第一篇论文中，提出了一种基于颗粒传播距离的替代土壤侵蚀模型（Mahlan-Model for Assessing Hillslope-Landscape Erosion，Runoff And Nutrients），本文介绍了该模型的两个评估中的第一个。敏感性分析表明，该数值模型与Parsons等人（2004年）的分析模型一致，并表明山坡上泥沙通量的下坡模式是降雨强度、持续时间和模式;山坡坡度;表面粗糙度和泥沙粒径的复杂相互作用。这一结果表明，山坡上沉积物转移的空间尺度是一个不平凡的问题，并且会因点而异，因事件而异，因此每年都会有所不同。根据18 m × 35 m地块上降雨模拟试验的现场数据对模型进行了评估，其中有径流水力学和泥沙通量的子地块尺度数据。结果表明，该模型能够再现沉降图，总体归一化均方根误差为18.4%，Nash-Sutcliffe效率为0.90。一旦针对特定土壤条件优化侵蚀参数，侵蚀沉积物粒度分布的空间和时间模式也可以很好地再现。版权所有© 2008约翰威利父子有限公司.
In the first paper in this series, we demonstrated that most process‐based erosion models have a series of in‐built assumptions that led us to question their true process basis. An alternative soil‐erosion model (Mahleran – Model for Assessing Hillslope‐Landscape Erosion, Runoff And Nutrients) based upon particle‐travel distance has been presented in the first paper in this series and this paper presents the first of two evaluations of the model. Here, a sensitivity analysis shows that the numerical model is consistent with the analytical model of Parsons et al. (2004) and demonstrates that downslope patterns of sediment flux on hillslopes are a complex interaction of rainfall intensity, duration and pattern; hillslope gradient; surface roughness and sediment size. This result indicates that the spatial scaling of sediment transfers on hillslopes is a non‐trivial problem and will vary from point to point and from event to event and thus from year to year. The model is evaluated against field data from a rainfall‐simulation experiment on an 18 m × 35 m plot for which there are sub‐plot‐scale data on runoff hydraulics and sediment flux. The results show that the model is capable of reproducing the sedigraph with an overall normalized root‐mean‐square error of 18·4% and Nash–Sutcliffe efficiency of 0·90. Spatial and temporal patterns of particle‐size distributions of the eroded sediment are also reproduced very well, once erosion parameters have been optimized for the specific soil conditions. Copyright © 2008 John Wiley & Sons, Ltd.