Item: .physical models for determining changes in microstructure of snow during metamorphism
Title: .physical models for determining changes in microstructure of snow during metamorphism
Proceedings: Proceedings of the 2000 International Snow Science Workshop, October 1-6, Big Sky, Montana
Authors: R. L. Brown Civil engineering Department, Montana State University, Bozeman, MT 59717 P. K. Satyawali, SASE, Site Office 3167, Sector 240, Chandigarh 160023, India Michael Lehning and Perry Bartelt Swiss Federal Institute for Snow and Avalanche Resea
Abstract: Since the internal microstructure is important for determining the mechanical, thermal and physical properties of snow, a study was undertaken to develop a physical model that can predict changes in microstructure of snow due to metamorphism and mechanical loads. The microstructure was defined in terms of the 3-D coordination number, mean grain size, mean bond radius and mean neck length. For situations where temperature gradients were small, a mixture theory was used to calculate growth for grains and bonds. These calculated results were then compared with experimental data and found to adequately predict changes in these variables. In situations where temperature gradient effects dominate, a physical model was developed which calculated grain and bond growth rates. This model was found to give results that appear to be representative of what happens in snow under TG conditions However, a lack of data to date has precluded a thorough evaluation. For mechanical effects, another physical model was developed to determine bond growth rates due to stresses applied to the snow. These models have been incorporated into the SNOWPACK program, which was developed by the Swiss Federal Institute for Snow and Avalanche Research as a tool for assisting avalanche hazard forecasters.
Keywords: snow, microstructure, metamorphism, sintering
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