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| Titel |
The effect of a rainfall and discharge variability on erosion rates in a highly active tectonic setting: a stochastic approach |
| VerfasserIn |
Jean Braun, Eric Deal, Christoff Andermann |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250111341
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| Publikation (Nr.) |
 EGU/EGU2015-11446.pdf |
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| Zusammenfassung |
| The influence of climate on surface processes and consequently on landscape evolution is
undeniably important; despite this, many fluvial landscape evolution models do
not integrate an accurate or physically based parameterisation of precipitation, the
climatic forcing most important for fluvial processes. This is likely due to two major
challenges; first of all there is the difficulty in moving from the hourly, daily and
monthly timescales most relevant to precipitation to the millennial timescales used in
landscape evolution modelling. To confront this challenge, we adopt the approach of
Tucker and Bras, 2000 and Lague, 2005, and upscale precipitation with a statistical
parameterisation accounting for mean precipitation as well as short term (daily) variability.
This technique is key in capturing and quantifying the importance of rare, extreme
events.
The second challenge stems from the fact that erosion rates are proportional not to
precipitation, but rather to discharge, which results from a complex convolution of the
regional precipitation patterns with the landscape. To address this second obstacle we present
work that investigates the relationship between a stochastic description of precipitation and
one of discharge, linking general patterns of precipitation and discharge rather than
attempting to establish a deterministic relationship. To achieve this we model the effect of
precipitation variability on runoff variability as well as compare associated precipitation and
discharge measurements from a range of climatic regimes and spatial scales in the
Himalayas. Using the results of this work, we integrate the statistical parameterisation of
precipitation into a landscape evolution model, allowing us to explore the effect of realistic
precipitation patterns, specifically precipitation variability, on the evolution of relief and
topography.
References
Bras, R. L., & Tucker, G. E. (2000). A stochastic approach to modeling the role of rainfall
variability in drainage basin evolution. Water Resources Research, 36(7), 1953-1964.
doi:10.1029/2000WR900065
Lague, D. (2005). Discharge, discharge variability, and the bedrock channel profile.
Journal of Geophysical Research, 110(F4), F04006. doi:10.1029/2004JF000259 |
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