A Trace Gas Method of Evaluating Wind-enhancement of Interstitial Air Movement in Snow

Abstract:

Air movement in snow affects chemical and vapor transport within the snowpack and subsequent atmospheric exchange. To examine the effect of wind on mobility of air within the snowpack pore space we deployed four snow pickets, each mounted with seven carbon monoxide sensors at two sites in the Pacific Cascades during the 2013-2014 winter season. For each deployment we released a neutrally buoyant puff of carbon monoxide from a point source and measured the evolution of its concentration within the snow. We simultaneously measured wind forcing at high frequency with a sonic anemometer placed directly above the carbon monoxide sensors. By comparing the analytical solution for the diffusion of a concentrated puff in a porous medium of known permeability with the measured dispersion we then evaluated the effect of wind on air movement within the snow.