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Titel |
The effect of background hydrometeorological conditions on the sensitivity of evapotranspiration to model parameters: analysis with measurements from an Italian alpine catchment |
VerfasserIn |
N. Montaldo, V. Toninelli, J. D. Albertson, M. Mancini, P. A. Troch |
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 ; 7, no. 6 ; Nr. 7, no. 6, S.848-861 |
Datensatznummer |
250004859
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Publikation (Nr.) |
copernicus.org/hess-7-848-2003.pdf |
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Zusammenfassung |
Recent developments have made land-surface models (LSMs) more complex through
the inclusion of more processes and controlling variables, increasing numbers of parameters
and uncertainty in their estimates. To overcome these uncertainties, prior to applying a
distributed LSM over the whole Toce basin (Italian Alps), a field campaign was carried out
at an experimental plot within the basin before exploring the skill and parameter
importance (sensitivity) using the TOPLATS model, an existing LSM. In the summer and
autumn of 1999, which included both wet (atmosphere controlled) and dry (soil controlled)
periods, actual evapotranspiration estimates were performed using Bowen ratio and, for a
short period, eddy correlation methods. Measurements performed with the two methods are in
good agreement. The calibrated LSM predicts actual evapotranspiration quite well over the
whole observation period. A sensitivity analysis of the evapotranspiration to model
parameters was performed through the global multivariate technique during both wet and dry
periods of the campaign. This approach studies the influence of each parameter without
conditioning on certain values of the other variables. Hence, all parameters are varied
simultaneously using, for instance, a uniform sampling strategy through a Monte Carlo
simulation framework. The evapotranspiration is highly sensitive to the soil parameters,
especially during wet periods. However, the evapotranspiration is also sensitive to some
vegetation parameters and, during dry periods, wilting point is the most critical for
evapotranspiration predictions. This result confirms the importance of correct
representation of vegetation properties which, in water-limited conditions, control
evapotranspiration.
Keywords: evapotranspiration, sensitivity analysis, land surface model, eddy
correlation, Alpine basin |
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