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

Titel Englisch MEASUREMENT AND SIMULATION OF SNOW METAMORPHISM AND EFFECTIVE TRANSPORT PROPERTIES UNDER ADVECTIVE CONDITIONS USING IN-SITU MICRO-TOMOGRAPHY
Gesuchsteller/in Steinfeld Aldo
Nummer 141017
Förderungsinstrument Projektförderung (Abt. I-III)
Forschungseinrichtung Institut für Energietechnik ETH Zürich
Hochschule ETH Zürich - ETHZ
Hauptdisziplin Fluiddynamik
Beginn/Ende 01.07.2012 - 30.09.2015
Bewilligter Betrag 174'777.00
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Alle Disziplinen (3)

Disziplin
Fluiddynamik
Andere Gebiete der Erdwissenschaften
Hydrologie, Limnologie, Glaziologie

Keywords (2)

Mass transport; Recrystallization

Lay Summary (Englisch)

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.

Direktlink auf Lay Summary Letzte Aktualisierung: 21.02.2013

Verantw. Gesuchsteller/in und weitere Gesuchstellende

Mitarbeitende

Publikationen

Publikation
Metamorphism during temperature gradient with undersaturated advective airflow in a snow sample
(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
(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
(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
(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.

Wissenschaftliche Veranstaltungen

Aktiver Beitrag

Titel Art des Beitrags Titel des Artikels oder Beitrages Datum Ort Beteiligte Personen
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, Vereinigte Staaten von Amerika Ebner Pirmin Philipp;


Verbundene Projekte

Nummer Titel Start Förderungsinstrument
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 Projektförderung (Abt. 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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