Quantifying grain-shape changes in snow subjected to large temperature gradients

Abstract

Snow-cover models are used in many applications in today's snow and ice research. Although physically based models allow the evolution of the internal structure of the snow cover to be followed very closely, a quantitative and objective description of the layer texture's evolution in snow subjected to large temperature gradients is still required, in order to both improve and verify existing snow-cover models. Based on experiments done in the cold laboratory as well as on field observations on snow subjected to kinetic-growth metamorphism, we present new results on the quantification of texture-related parameters. Problems such as linking objective laboratory work to pragmatic field observations and finding a reproducible method to measure shape-related parameters are discussed. Finally, a new shape parameter is proposed, zero curvature, which differentiates well between depth hoar, faceted crystals and snow types with rounded grains. It also shows a pronounced dependence on temperature gradient.