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| Titel |
Verification of the multi-layer SNOWPACK model with different water transport schemes |
| VerfasserIn |
N. Wever, L. Schmid, A. Heilig, O. Eisen, C. Fierz, 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 ; 9, no. 6 ; Nr. 9, no. 6 (2015-12-07), S.2271-2293 |
| Datensatznummer |
250116880
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| Publikation (Nr.) |
 copernicus.org/tc-9-2271-2015.pdf |
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| Zusammenfassung |
| The widely used detailed SNOWPACK model has undergone constant development
over the years. A notable recent extension is the introduction of a Richards
equation (RE) solver as an alternative for the bucket-type approach for
describing water transport in the snow and soil layers. In addition,
continuous updates of snow settling and new snow density parameterizations
have changed model behavior. This study presents a detailed evaluation of
model performance against a comprehensive multiyear data set from
Weissfluhjoch near Davos, Switzerland. The data set is collected by automatic
meteorological and snowpack measurements and manual snow profiles. During the
main winter season, snow height (RMSE: < 4.2 cm), snow water equivalent
(SWE, RMSE: < 40 mm w.e.), snow temperature distributions (typical
deviation with measurements: < 1.0 °C) and snow density (typical
deviation with observations: < 50 kg m−3) as well as their temporal
evolution are well simulated in the model and the influence of the two water
transport schemes is small. The RE approach reproduces internal differences
over capillary barriers but fails to predict enough grain growth since the
growth routines have been calibrated using the bucket scheme in the original
SNOWPACK model. However, the agreement in both density and grain size is
sufficient to parameterize the hydraulic properties successfully. In the melt
season, a pronounced underestimation of typically 200 mm w.e. in SWE is
found. The discrepancies between the simulations and the field data are
generally larger than the differences between the two water transport
schemes. Nevertheless, the detailed comparison of the internal snowpack
structure shows that the timing of internal temperature and water dynamics is
adequately and better represented with the new RE approach when compared to
the conventional bucket scheme. On the contrary, the progress of the
meltwater front in the snowpack as detected by radar and the temporal
evolution of the vertical distribution of melt forms in manually observed
snow profiles do not support this conclusion. This discrepancy suggests that
the implementation of RE partly mimics preferential flow effects. |
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