Capillary Rise in Snow
Ccile Colou1, Ke Xu2, Bernard Lesaffre1, and Jean-Bruno Brzoska1
Snow is a complex porous medium where liquid water may rise to several centimeters high due to
capillary rise.
Previous experimental measurements in a cold laboratory on wet snow samples allowed us to relate
the capillary rise level with snow characteristics (porosity, grain size).
In this study, a network model was adapted to snow to simulate this phenomenon. The pore texture
of a wet snow block is simulated by a cubic lattice of cylindrical bonds. Bond lengths are the same,
equal to the mesh size of the lattice. Their circular sections vary with the two-dimensional pore size
distribution, computed from image analysis of thin sections. At a given height, a bond contains water
if the two following conditions are fulfilled: first, it should be thin enough in radius so that capillary
pressure balances hydrostatic pressure at this level; second, there exists a continuous path of such
bonds that connects the bottom of the lattice.
Simulations were systematically compared to observations of the maximum level of capillary rise
for ten different snow samples. Simulated and experimental results varied in the same direction.
Difference between simulation and measurement varied from 0.5 to 2.8 cm when the height of cap-
illary rise varied from 1 to 10 cm. We could infer from previous results that the ratio of the mean
convex radius of curvature to density contained relevant information on pore size. Simulated profiles
of liquid water content were compared to vertical thin sections of three refrozen samples of saturated
snow. They decreased too slowly above the fully saturated layer.
1
Meteo-France, Centre National de Recherches Mtorologiques, Centre d'Etudes de la Neige, 1441 rue de
la piscine, F-38406 Saint Martin d'Hres Cedex, FRANCE
2 Laboratoire de Physique des phnomnes de Transport et de Mlange, Bd3, Tlport2, BP79, 86960 Futur-
oscope, FRANCE
45
Previous Page
