The influence of pollution on solar heating and melting of a snowpack

Abstract

The effect of impurities in snow on solar heating and possible melting of a layered snowpack is studied using the developed computational model for the spectral radiative transfer. The combined model includes different approaches for two spectral regions. The recently obtained analytical solution based on the two-flux method for the diffuse component of the radiation intensity is employed in a part of the infrared range, where pure snow is almost opaque and impurities do not affect the radiation field. On the contrary, the numerical procedure, which takes into account the layered structure of polluted snow is used in the visible and adjacent near-infrared spectrum. Small soot particles are considered as a representative component of the impurities. Both the externally mixed and the internally mixed soot particles inside the ice grains are considered. The recently developed numerical procedure for transient heat transfer calculations taking into account heat conduction, convective heat transfer at the snow surface and radiative cooling in the atmospheric window of transparency is employed to estimate a contribution of the layered impurity on heating and melting of snow. Some computational results for the problem typical of the Arctic summer are discussed. It is shown that the local impurities may lead to considerable additional heating of deep layers of snow. The effect of a strongly polluted snow surface layer is also considered.