Thermal conductivity of polar firn
Abstract The vast Greenland and Antarctic Ice Sheets are covered by many tens of meters of polar firn, which is snow that is years to centuries old and has experienced significant metamorphism. Both ice-sheet modeling and decoding satellite data require knowledge of the thermal conductivity of polar...
| Published in: | Journal of Glaciology |
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| Main Authors: | , |
| Other Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
2022
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1017/jog.2022.28 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143022000284 |
| Summary: | Abstract The vast Greenland and Antarctic Ice Sheets are covered by many tens of meters of polar firn, which is snow that is years to centuries old and has experienced significant metamorphism. Both ice-sheet modeling and decoding satellite data require knowledge of the thermal conductivity of polar firn with depth, yet direct measurements are not available for depths below the top several meters. We present the first direct measurements of the effective thermal conductivity of polar firn over depths down to 48 m. A custom guarded hot plate has been designed and constructed, and validation of this device using materials of known thermal conductivity is presented. Using the validated device, measurements were made on firn core samples spanning depths from 4 to 48 m from an undisturbed site near the South Pole, Antarctica. Results show that the thermal conductivity of polar firn at South Pole increases with depth and with density. The thermal conductivity of polar firn from the surface to 48 m depth is well-explained as a function of density by the relationship k firn ( ρ ) = 0.144 e 0.00308· ρ and as a function of depth by the relationship k firn ( z ) = 0.536 e 0.0144· z . The associated thermal diffusivities range from 19.0 to 28.5 m 2 a -1 . |
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