TCD The Cryosphere Discussions TCD 1994-0440 Copernicus GmbH Göttingen, Germany 10.5194/tcd-6-2305-2012 Investigating the dynamics of bulk snow density in dry and moist conditions using a one-dimensional model De Michele C. 1 Avanzi F. 1 Ghezzi A. 1 Jommi C. 2 DIIAR-Politecnico di Milano, Piazza L. da Vinci 32, Milano I20133, Italy DIS-Politecnico di Milano, Piazza L. da Vinci 32, Milano I20133, Italy 04 07 2012 6 4 2305 2325 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.the-cryosphere-discuss.net/6/2305/2012/tcd-6-2305-2012.html The full text article is available as a PDF file from http://www.the-cryosphere-discuss.net/6/2305/2012/tcd-6-2305-2012.pdf

Snowpack is a complicated multiphase mixture with mechanical, hydraulic, and thermal properties, highly variable within the year in response to climatic forcings. Bulk density is a macroscopic property of the snowpack used, together with snow depth, to quantify the water stored. In seasonal snowpacks, the bulk density is characterized by a strong non-linear behaviour due to the occurrence of both dry and wet conditions. In literature, bulk snow density estimates are obtained principally with multiple regressions, and snowpack models have put the attention principally on the snow depth and snow water equivalent. Here a one-dimensional model for the temporal dynamics of the bulk snow density has been proposed, accounting for both dry and moist conditions. The model assimilates the snowpack to a two-constituent mixture: a dry part including ice structure, and air, and a wet part constituted by liquid water. It describes the dynamics of three variables: the depth and density of the dry part and the depth of liquid water. The model has been calibrated and validated against hourly data registered in two SNOTEL stations, Western US, with mean values of the Nash-Sutcliffe coefficient ≈0.90–0.92.

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