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| Titel |
A comprehensive approach to analyze discrepancies between land surface models and in-situ measurements: a case study over the US and Illinois with SECHIBA forced by NLDAS |
| VerfasserIn |
M. Guimberteau, A. Perrier, K. Laval, J. Polcher |
| 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 ; 16, no. 11 ; Nr. 16, no. 11 (2012-11-05), S.3973-3988 |
| Datensatznummer |
250013553
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| Publikation (Nr.) |
 copernicus.org/hess-16-3973-2012.pdf |
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| Zusammenfassung |
| The purpose of this study is to test the ability of the Land Surface Model SECHIBA to simulate
water budget and particularly soil moisture at two different scales: regional and local. The
model is forced by NLDAS data set at 1/8th degree resolution over the 1997–1999 period. SECHIBA
gives satisfying results in terms of evapotranspiration and runoff over the US compared with four
other land surface models, all forced by NLDAS data set for a common time period. The simulated
soil moisture is compared to in-situ data from the Global Soil Moisture Database across Illinois
by computing a soil wetness index. A comprehensive approach is performed to test the ability of
SECHIBA to simulate soil moisture with a gradual change of the vegetation parameters closely
related to the experimental conditions. With default values of vegetation parameters, the model
overestimates soil moisture, particularly during summer. Sensitivity tests of the model to the
change of vegetation parameters show that the roots extraction parameter has the
largest impact on soil moisture, other parameters such as LAI, height or soil resistance having
a minor impact. Moreover, a new evapotranspiration computation including bare soil evaporation
under vegetation has been introduced into the model. The results point out an improvement of the
soil moisture simulation when this effect is taken into account. Finally, soil moisture sensitivity
to precipitation variation is addressed and it is shown that soil moisture observations
can be rather different, depending on the method of measuring field
capacity. When the observed field capacity is deducted from the observed volumetric water
profiles, simulated soil wetness index is closer to the observations. |
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