Reconstructing Thermal Properties of Firn at Summit, Greenland, from a Temperature Profile Time Series
We have constrained the value for thermal diffusivity of near-surface snow and firn at Summit Station, Greenland, using a Fourier-type analysis applied to hourly temperature measurements collected from eight thermistors in a closed-off, air-filled borehole between May 2004 and July 2008. An implicit...
| Published in: | Journal of Glaciology |
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| Main Authors: | , |
| Format: | Text |
| Language: | unknown |
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Dartmouth Digital Commons
2015
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| Subjects: | |
| Online Access: | https://digitalcommons.dartmouth.edu/facoa/1751 https://doi.org/10.3189/2015JoG14J204 https://digitalcommons.dartmouth.edu/context/facoa/article/2754/viewcontent/t14j204.pdf |
| Summary: | We have constrained the value for thermal diffusivity of near-surface snow and firn at Summit Station, Greenland, using a Fourier-type analysis applied to hourly temperature measurements collected from eight thermistors in a closed-off, air-filled borehole between May 2004 and July 2008. An implicit, finite-difference method suggests that a bulk diffusivity of ∼25 ± 3m2 a−1 is the most reasonable for representing macroscale heat transport in the top 30 m of firn and snow. This value represents an average diffusivity and, in a conduction-only model, generates temperature series whose phase shifts with depth most closely match those of the Summit borehole data (rms difference between measurements and model output is ∼6 days). This bulk value, derived numerically and corroborated analytically, is useful over large tracts of the Greenland ice sheet where density and microstructure are unknown. |
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