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Measurement and simulation of snow metamorphism and effective transport properties under advective conditions using in-situ micro-tomography

English title MEASUREMENT AND SIMULATION OF SNOW METAMORPHISM AND EFFECTIVE TRANSPORT PROPERTIES UNDER ADVECTIVE CONDITIONS USING IN-SITU MICRO-TOMOGRAPHY
Applicant Steinfeld Aldo
Number 141017
Funding scheme Project funding (Div. I-III)
Research institution Institut für Energietechnik ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Fluid Dynamics
Start/End 01.07.2012 - 30.09.2015
Approved amount 174'777.00
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All Disciplines (3)

Discipline
Fluid Dynamics
Other disciplines of Earth Sciences
Hydrology, Limnology, Glaciology

Keywords (2)

Mass transport; Recrystallization

Lay Summary (English)

Lead
Lay summary

Using in-situ micro-tomography of representative snow samples, an experimental system will be developed for investigating the snow metamorphism under airflow. In-situ time-lapse experimental runs will be first conducted using micro computer tomography (μCT) on quasi-isothermal snow, and then extended on snow under a temperature gradient. The 3D digital representations of snow samples will be obtained by μCT and applied 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. Finally, phase-field modeling will simulate the observed evolution of the microstructure. Of special focus is the accurate determination of the effective permeability and thermal conductivity. Vapor mass flux and recrystallization rate will be determined using an adapted version of particle image velocimetry based on time-lapse images.

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 research proposed has crucial significance to a wide range of environmental processes, including evolution of the snowpack in arctic regions, and flux mechanism of trace gases exchanged between the ground and atmospheric air. This project will enable the determination of more accurate effective transport properties, which in turn can be incorporated in forecasting models of late-stage alpine snowpack responsible for large-scale avalanches.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Metamorphism during temperature gradient with undersaturated advective airflow in a snow sample
Ebner Pirmin Philipp, Schneebeli Martin, Steinfeld Aldo (2016), Metamorphism during temperature gradient with undersaturated advective airflow in a snow sample, in The Cryosphere, 10(2), 791-797.
Tomography-based characterization of ice-air interface dynamics of temperature gradient snow metamorphism under advective conditions
Ebner Pirmin Philipp, Andreoli Christian, Schneebeli Martin, Steinfeld Aldo (2015), Tomography-based characterization of ice-air interface dynamics of temperature gradient snow metamorphism under advective conditions, in Journal of Geographical Research, 120(12), 2437-2451.
Tomography-based monitoring of isothermal snow metamorphism under advective conditions
Ebner Pirmin Philipp, Schneebeli Martin, Steinfeld Aldo (2015), Tomography-based monitoring of isothermal snow metamorphism under advective conditions, in The Cryosphere, 9, 1363-1371.
An instrumented sample holder for time-lapse micro-tomography measurements of snow under advective conditions
Ebner Pirmin Philipp, Grimm Sascha, Schneebeli Martin, Steinfeld Aldo (2014), An instrumented sample holder for time-lapse micro-tomography measurements of snow under advective conditions, in Geoscientific Instrumentation Methods and Data Systems, 3, 179-185.

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
American Geophysical Union Fall Meeting 2014 Poster Time-lapse micro-tomography measurements and determination of effective transport properties of snow metamorphism under advective conditions and isotopes 15.12.2014 San Francisco, United States of America Ebner Pirmin Philipp;


Associated projects

Number Title Start Funding scheme
155999 The impact of the physical micro-environment of impurities in snow on their re-distribution during metamorphism, chemical reactivity, and transfer to ice core archives. 01.05.2015 Project funding (Div. I-III)

Abstract

Using in-situ micro-tomography of representative snow samples, we plan to develop an experimental system where metamorphism under airflow can be quantified. In-situ time-lapse experimental runs will be first conducted in micro computer tomography (µCT) on quasi-isothermal snow, and then extended on snow under a temperature gradient. A new sample holder will be designed for these experiments. Effective heat and mass transport properties, as well as diffusion and advection processes at the pore level, will be determined by direct pore-level numerical simulations and validated with direct measurements. Finally, phase-field modeling will simulate the observed evolution of the microstructure.The 3D geometrical representations of snow samples will be obtained by 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. Of special focus is the accurate determination of the effective permeability and thermal conductivity. Vapor mass flux and recrystallization rate will be determined using an adapted version of particle image velocimetry based on time-lapse images. We will examine the coupling between recrystallization rate and permeability for experiments with an imposed temperature gradient under advective conditions.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 research proposed has crucial significance to a wide range of environmental processes, as 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.
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