SNF Project – Snow Metamorphism and Effective Transport Properties under Advective Conditions using In-situ Micro-Tomography

Funding source: external page Swiss National Science Foundation
Partners: external page WSL-Institute for Snow and Avalanche Research SLF

Background – Snow, a sintered porous material made of ice grains, has a complex porous microstructure that continuously changes with time and external conditions. Its effective mass transport properties, strongly dependent on the complex microstructure, are relevant for investigating a wide range of environmental processes.

Objectives – This project is aimed at quantifying snow metamorphism under advective airflow. Experiments, numerical simulation at the pore- and structure-level, and phase-field simulations will be combined. The hypothesis that the airflow will enhance recrystallization rate, increase structural change, and increase isotopic segregation, will be analyzed. The specific objective is to quantify the rates of these different processes. The 3D geometrical representations of snow samples will be obtained by micro-computed tomography (μCT) and used in direct pore-level simulations (DPLS) to numerically solve the governing mass, momentum, and energy conservation equations, allowing for the determination of the snow’s effective transport properties (e.g. permeability) and validated with direct measurements. Finally, phase-field modeling will simulate the observed evolution of the microstructure.

A functional understanding of snow metamorphism combined with airflow will give more in-depth understanding of the snow structure observed in polar and alpine regions. The results of our experiments and simulations can be used for improving models of firn compaction and evolution, for understanding evolution of the snowpack in arctic regions, for elucidating the flux mechanism of trace gases exchanged between the ground and atmospheric air, and for providing more accurate effective transport properties to forecasting models of late-stage alpine snowpack responsible for large scale avalanches.