Abstract

The influence of climate on landform evolution has received great interest over the past decades. While many studies aim at determining erosion rates or parameters of erosion models, feedbacks between tectonics, climate and landform evolution have been discussed, but addressed quantitatively only in a few modeling studies. One of the problems in this field is that coupling a large-scale landform evolution model with a general circulation model would dramatically increase the theoretical and numerical complexity. Only a few simple models are available so far that allow a numerical efficient coupling between topography-controlled precipitation and erosion. This paper fills this gap by introducing a quite simple approach involving two vertically integrated moisture components (vapor and cloud water). The interaction between both components is linear and depends on altitude. This model structure is in principle the simplest approach that is able to predict both orographic precipitation at small scales and a large-scale decrease in precipitation over continental areas without introducing additional assumptions. Even in combination with transversal dispersion and height-dependent evapotranspiration, the model is of linear time complexity and increases the computing effort of efficient large-scale landform evolution models only moderately. Even simple numerical experiments applying such a coupled landform evolution model show the strong impact of spatial precipitation gradients on mountain range geometry including steepness and peak elevation, position of the principal drainage divide, and drainage network properties.

Highlights

  • This paper fills this gap by introducing a quite simple approach involving two vertically integrated moisture components. The interaction between both components is linear and depends on altitude. This model structure is in principle the simplest approach that is able to predict both orographic precipitation at small scales and a large-scale decrease in precipitation over continental areas without introducing additional 10 assumptions

  • This study presents a new model for orographic precipitation for use in large-scale landform evolution models such as the 590 stream-power incision model (SPIM) or the shared stream-power model

  • We arrived at a model with two moisture components, which are interpreted as vapor and cloud water

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Summary

Introduction

The redistribution of moisture from the oceans towards continental domains governs the global erosion engine. The models proposed by Roe et al (2003), Smith and Barstad (2004), and Garcia-Castellanos (2007) use the concept 60 of vertically integrated water contents and the respective fluxes per unit width. The model proposed by Smith and Barstad (2004) defines two components, interpreted as cloud water and hydrometeors This model focuses on condensation and fallout at small scales, while it cannot predict transport over long distances. Using a quite ingenious approach for describing deviations from equilibrium, it is able to capture the increase in precipitation with altitude as well the slow decrease in precipitation with increasing distance from the ocean It requires an artificial smoothing at small scales, to the model of Roe et al (2003).

The governing equations
The effect of topography
Boundary conditions
Numerical implementation
Characteristic length scales
The influence of transversal dispersion
Extension by evapotranspiration
Comparison to existing models
Impact of continentality on landform evolution
Conclusions
Findings
635 References
Full Text
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