A DRY SNOW PACK MODEL

A dry snow pack is viewed as an interacting mixture of rigid ice grains and air occupying the pore space in the matrix. The three-dimensional mass, momentum and energy balances are formulated within the framework of interacting continua theory. The assumption of a common ice and air temperature is made to reflect the very slow relative motion between the air and ice. Focusing on a one-dimensional vertical snow pack, five constitutive postulates and two external prescriptions are made to obtain a closed system of partial differential equations. We consider the response of the snow pack to surface forcing by annual variations of heat flux and pressure. Nondimensional analysis of the differential equations and surface conditions determines the major balances and leads to a reduced model. The equations are solved numerically for the temperature, air velocity, density and pressure through the snow pack resulting from both thermal forcing and pressure forcing at the surface.