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| Titel |
Seasonal evolution of snow permeability under equi-temperature and temperature-gradient conditions |
| VerfasserIn |
F. Domine, S. Morin, E. Brun, M. Lafaysse, C. M. Carmagnola |
| 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 ; 7, no. 6 ; Nr. 7, no. 6 (2013-12-18), S.1915-1929 |
| Datensatznummer |
250085193
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| Publikation (Nr.) |
 copernicus.org/tc-7-1915-2013.pdf |
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| Zusammenfassung |
| The permeability (K) of snow to air flow affects the transfer of energy, water vapor and chemical species between the snow and
the atmosphere. Yet today little is known about the temporal evolution of snow permeability as a function of metamorphic
regime. Furthermore, our ability to simulate snow permeability over the seasonal evolution of a snowpack has not been
tested. Here we have measured the evolution of snow permeability in a subarctic snowpack subject to high temperature-gradient
(TG) metamorphism. We have also measured the evolution of the same snowpack deposited over tables so that it evolved in the
equi-temperature (ET) regime. Permeability varies in the range 31 × 10−10 (ET regime) to 650 × 10−10
m2 (TG regime). Permeability increases over time in TG conditions and decreases under ET conditions. Using measurements of
density ρ and of specific surface area (SSA), from which the equivalent sphere radius r is determined, we show that the
equation linking SSA, density ρ and permeability, K = 3.0 r2 e(−0.013 ρ) (with K in m2, r in m and
ρ in kg m−3) obtained in a previous study adequately predicts permeability values. The detailed snowpack model Crocus is used to simulate the
physical properties of the TG and ET snowpacks. For the most part, all variables are well reproduced.
Simulated permeabilities
are up to a factor of two greater than measurements for depth hoar layers,
which we attribute to snow microstructure and its aerodynamic properties.
Finally, the large difference in
permeabilities between ET and TG metamorphic regimes will impact atmosphere-snow energy and mass exchanges. These effects
deserve consideration in predicting the effect of climate change on snow properties and snow–atmosphere interactions. |
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