Ripening processes and meltwater movement in Arctic snowpacks

Abstract

<p>This is a study of the processes controlling snowpack ripening and the movement of meltwater through wet snowpacks. Measurements made in the Canadian High Arctic during the 1979, 1980, and 1981 snowmelt periods, included premelt stratigraphy, surface energy balance, physical changes in snowpack properties during melt, snow and soil temperatures, and water movement within the pack. Field observations and computer modelling demonstrated an interdependence of finger flow at the wetting front and ice layer growth at premelt snow horizons. Ice layers grow rapidly in cold snowpacks, slowing the finger wetting front advance and releasing considerable latent heat which warms the underlying snow and toil. Since the ground is frozen when water reaches the ground surface, the meltwater refreezes at the snowpack base. The growth of this basal ice layer limits the amount of water available for daily runoff and extends the melt period, a phenomenon which is typical of cold arctic snowpacks. A redistribution of flow within the snowpack, concentrating flow in certain areas and diminishing it in others, is due to variations in ice layer properties, and not flow instabilities or vertical flow channels. The re sult is a spread of the rising limb of the melt wave at depth and a decrease of the peak flow. Results from a multiple flow path model, suggest that flow variability is similar in snowpacks from different environments. This indicates that the model is applicable to snowpacks in a wide range of environments.</p>