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Thermal Conductivity of Snow, Firn, and Porous Ice From 3‐D Image‐Based Computations
Author(s) -
Calonne Neige,
Milliancourt Lucas,
Burr Alexis,
Philip Armelle,
Martin Christophe L.,
Flin Frederic,
Geindreau Christian
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl085228
Subject(s) - firn , snow , glacier , thermal conductivity , geology , porosity , permafrost , ice core , geomorphology , atmospheric sciences , materials science , mineralogy , composite material , climatology , geotechnical engineering , oceanography
Estimating thermal conductivity of snow, firn, and porous ice is key for modeling the thermal regime of alpine and polar glaciers. Whereas thermal conductivity of snow was widely investigated, studies on firn and porous ice are very scarce. This study presents the effective thermal conductivity tensor computed from 64 3‐D images of microstructures of snow, antarctic firn, and porous ice at −3, −20, and −60°C. We show that, in contrast with snow, conductivity of firn and porous ice correlates linearly with density, is approximately isotropic, and is largely impacted by temperature. We report that performances of commonly used estimates of thermal conductivity vary largely with density. In particular, formulas designed for snow lead to significant underestimations when applied to denser ice structures. We present a new formulation to accurately estimate the thermal conductivity throughout the whole density range, from fresh snow to bubbly ice, and for any temperature conditions encountered in glaciers.