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| Titel |
2-way coupling the hydrological land surface model PROMET with the regional climate model MM5 |
| VerfasserIn |
F. Zabel, W. Mauser |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 17, no. 5 ; Nr. 17, no. 5 (2013-05-02), S.1705-1714 |
| Datensatznummer |
250018866
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| Publikation (Nr.) |
 copernicus.org/hess-17-1705-2013.pdf |
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| Zusammenfassung |
Most land surface hydrological models (LSHMs) consider land surface processes
(e.g. soil–plant–atmosphere interactions, lateral water flows, snow and
ice) in a spatially detailed manner. The atmosphere is considered as
exogenous driver, neglecting feedbacks between the land surface and the
atmosphere. On the other hand, regional climate models (RCMs) generally
simulate land surface processes through coarse descriptions and spatial
scales but include land–atmosphere interactions. What is the impact of the
differently applied model physics and spatial resolution of LSHMs on the
performance of RCMs? What feedback effects are induced by different land
surface models? This study analyses the impact of replacing the land surface
module (LSM) within an RCM with a high resolution LSHM.
A 2-way coupling approach was applied using the LSHM PROMET
(1 × 1 km2)
and the atmospheric part of the RCM MM5 (45 × 45 km2).
The scaling interface SCALMET is used for down- and upscaling
the linear and non-linear fluxes between the model scales.
The change in the atmospheric response by MM5 using the LSHM is analysed, and
its quality is compared to observations of temperature and precipitation for a
4 yr period from 1996 to 1999 for the Upper Danube catchment. By
substituting the Noah-LSM with PROMET, simulated non-bias-corrected near-surface air temperature improves for annual, monthly and daily courses when
compared to measurements from 277 meteorological weather stations within the
Upper Danube catchment. The mean annual bias was improved from −0.85 to
−0.13 K. In particular, the improved afternoon heating from May to September
is caused by increased sensible heat flux and decreased latent heat flux as
well as more incoming solar radiation in the fully coupled PROMET/MM5 in
comparison to the NOAH/MM5 simulation. Triggered by the LSM replacement,
precipitation overall is reduced; however simulated precipitation amounts
are still of high uncertainty, both spatially and temporally. The
distribution of precipitation follows the coarse topography representation
in MM5, resulting in a spatial shift of maximum precipitation northwards of
the Alps. Consequently, simulation of river runoff inherits precipitation
biases from MM5. However, by comparing the water balance, the bias of annual
average runoff was improved from 21.2% (NOAH/MM5) to 4.4%
(PROMET/MM5) when compared to measurements at the outlet gauge of the
Upper Danube watershed in Achleiten. |
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