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| Titel |
Solving Richards Equation for snow improves snowpack meltwater runoff estimations in detailed multi-layer snowpack model |
| VerfasserIn |
N. Wever, C. Fierz, C. Mitterer, H. Hirashima, M. Lehning |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1994-0416
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| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 8, no. 1 ; Nr. 8, no. 1 (2014-02-20), S.257-274 |
| Datensatznummer |
250116021
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| Publikation (Nr.) |
 copernicus.org/tc-8-257-2014.pdf |
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| Zusammenfassung |
| The runoff from a snow cover during spring snowmelt or rain-on-snow events is
an important factor in the hydrological cycle. In this study, three water
balance schemes for the 1 dimensional physically-based snowpack model
SNOWPACK are compared to lysimeter measurements at two alpine sites with a
seasonal snow cover, but with different climatological conditions:
Weissfluhjoch (WFJ) and Col de Porte (CDP). The studied period consists of 14
and 17 yr, respectively. The schemes include a simple bucket-type
approach, an approximation of Richards Equation (RE), and the full RE. The
results show that daily sums of snowpack runoff are strongly related to a
positive energy balance of the snow cover and therefore, all water balance
schemes show very similar performance in terms of Nash-Sutcliffe efficiency
(NSE) coefficients (around 0.63 and 0.72 for WFJ and CDP, respectively)
and r2 values (around 0.83 and 0.72 for WFJ and CDP, respectively). An
analysis of the runoff dynamics over the season showed that the bucket-type
and approximated RE scheme release meltwater slower than in the measurements,
whereas RE provides a better agreement. Overall, solving RE for the snow
cover yields the best agreement between modelled and measured snowpack
runoff, but differences between the schemes are small. On sub-daily time
scales, the water balance schemes behave very differently. In that case,
solving RE provides the highest agreement between modelled and measured
snowpack runoff in terms of NSE coefficient (around 0.48 at both sites). At
WFJ, the other water balance schemes loose most predictive power, whereas at
CDP, the bucket-type scheme has an NSE coefficient of 0.39. The shallower
and less stratified snowpack at CDP likely reduces the differences between
the water balance schemes. Accordingly, it can be concluded that solving RE
for the snow cover improves several aspects of modelling snow cover runoff,
especially for deep, sub-freezing snow covers and in particular on the
sub-daily time scales. The additional computational cost was found to be in
the order of a factor of 1.5–2. |
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