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| Titel |
Sensitivity of hydro-geomorphic processes to catchment-scale variations in rainfall distribution |
| VerfasserIn |
Declan Valters, Simon Brocklehurst, David Schultz |
| 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 |
250109955
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| Publikation (Nr.) |
 EGU/EGU2015-9909.pdf |
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| Zusammenfassung |
| The dynamics of severe storms have a pronounced effect on the temporal and spatial
distribution of water input to river catchments in upland environments, particularly those with
complex orography and steep topographic gradients. Existing landscape evolution models
typically forsake realistic patterns of rainfall during storm events, in favour of uniform
rainfall input. It is demonstrated that this simplification fails to resolve localised areas of
flooding and erosion within a drainage basin, despite the known significance of erosion
thresholds and orographic enhancement of rainfall. This shortfall can be remedied
by the incorporation of high-resolution precipitation data from rainfall radar into
model simulations, accounting for sub-catchment-scale variation in precipitation
patterns.
Using a series of simulations with both synthetic and real topographies, it is shown that
there is a wide variation in hydro-geomorphic response observed in comparison to
simulations with spatially-averaged rainfall: localised water depths and erosion rates vary by
up to an order of magnitude within the catchments studied. The real-data examples, chosen
from severe UK rainfall events over the last 10 years, are analysed by combining the
CAESAR-Lisflood landscape evolution model at 5m resolution with data from the UK Met
Office NIMROD rainfall radar at 1km resolution. The model-coupling framework presented
is also suited to using output from weather forecasting models. The applications are
wide-ranging, from improving the accuracy of hydrological predictions during single storm
events, to understanding longer-term evolution of catchment-scale geomorphology. |
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