Use of a thermal imager for snow pit temperatures
Weak snow of interest to avalanche forecasting often forms and changes as thin layers. Thermometers, the current field technology for measuring the temperature gradients across such layers – and for thus estimating the expected vapour flux and future type of crystal metamorphism – are difficult to u...
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Language: | English |
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Copernicus Publications
2012
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Online Access: | https://doi.org/10.5194/tc-6-287-2012 http://www.the-cryosphere.net/6/287/2012/tc-6-287-2012.pdf https://doaj.org/article/ab8864b25fab4984a51f8e866012a38d |
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fttriple:oai:gotriple.eu:oai:doaj.org/article:ab8864b25fab4984a51f8e866012a38d 2023-05-15T18:32:23+02:00 Use of a thermal imager for snow pit temperatures C. Shea B. Jamieson K. W. Birkeland 2012-03-01 https://doi.org/10.5194/tc-6-287-2012 http://www.the-cryosphere.net/6/287/2012/tc-6-287-2012.pdf https://doaj.org/article/ab8864b25fab4984a51f8e866012a38d en eng Copernicus Publications doi:10.5194/tc-6-287-2012 1994-0416 1994-0424 http://www.the-cryosphere.net/6/287/2012/tc-6-287-2012.pdf https://doaj.org/article/ab8864b25fab4984a51f8e866012a38d undefined The Cryosphere, Vol 6, Iss 2, Pp 287-299 (2012) geo envir Journal Article https://vocabularies.coar-repositories.org/resource_types/c_6501/ 2012 fttriple https://doi.org/10.5194/tc-6-287-2012 2023-01-22T19:27:56Z Weak snow of interest to avalanche forecasting often forms and changes as thin layers. Thermometers, the current field technology for measuring the temperature gradients across such layers – and for thus estimating the expected vapour flux and future type of crystal metamorphism – are difficult to use at distances shorter than 1 cm. In contrast, a thermal imager can provide thousands of simultaneous temperature measurements across small distances with better accuracy. However, a thermal imager only senses the exposed surface, complicating its methods for access and accuracy of buried temperatures. This paper presents methods for exposing buried layers on pit walls and using a thermal imager to measure temperatures on these walls, correct for lens effects with snow, adjust temperature gradients, adjust time exposed, and calculate temperature gradients over millimetre distances. We find lens error on temperature gradients to be on the order of 0.03 °C between image centre and corners. We find temperature gradient change over time to usually decrease – as expected with atmospheric equalization as a strong effect. Case studies including thermal images and visual macro photographs of crystals, collected during the 2010–2011 winter, demonstrate large temperature differences over millimetre-scale distances that are consistent with observed kinetic metamorphism. Further study is needed to use absolute temperatures independently of supporting gradient data. Article in Journal/Newspaper The Cryosphere Unknown The Cryosphere 6 2 287 299 |
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language |
English |
topic |
geo envir |
spellingShingle |
geo envir C. Shea B. Jamieson K. W. Birkeland Use of a thermal imager for snow pit temperatures |
topic_facet |
geo envir |
description |
Weak snow of interest to avalanche forecasting often forms and changes as thin layers. Thermometers, the current field technology for measuring the temperature gradients across such layers – and for thus estimating the expected vapour flux and future type of crystal metamorphism – are difficult to use at distances shorter than 1 cm. In contrast, a thermal imager can provide thousands of simultaneous temperature measurements across small distances with better accuracy. However, a thermal imager only senses the exposed surface, complicating its methods for access and accuracy of buried temperatures. This paper presents methods for exposing buried layers on pit walls and using a thermal imager to measure temperatures on these walls, correct for lens effects with snow, adjust temperature gradients, adjust time exposed, and calculate temperature gradients over millimetre distances. We find lens error on temperature gradients to be on the order of 0.03 °C between image centre and corners. We find temperature gradient change over time to usually decrease – as expected with atmospheric equalization as a strong effect. Case studies including thermal images and visual macro photographs of crystals, collected during the 2010–2011 winter, demonstrate large temperature differences over millimetre-scale distances that are consistent with observed kinetic metamorphism. Further study is needed to use absolute temperatures independently of supporting gradient data. |
format |
Article in Journal/Newspaper |
author |
C. Shea B. Jamieson K. W. Birkeland |
author_facet |
C. Shea B. Jamieson K. W. Birkeland |
author_sort |
C. Shea |
title |
Use of a thermal imager for snow pit temperatures |
title_short |
Use of a thermal imager for snow pit temperatures |
title_full |
Use of a thermal imager for snow pit temperatures |
title_fullStr |
Use of a thermal imager for snow pit temperatures |
title_full_unstemmed |
Use of a thermal imager for snow pit temperatures |
title_sort |
use of a thermal imager for snow pit temperatures |
publisher |
Copernicus Publications |
publishDate |
2012 |
url |
https://doi.org/10.5194/tc-6-287-2012 http://www.the-cryosphere.net/6/287/2012/tc-6-287-2012.pdf https://doaj.org/article/ab8864b25fab4984a51f8e866012a38d |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
The Cryosphere, Vol 6, Iss 2, Pp 287-299 (2012) |
op_relation |
doi:10.5194/tc-6-287-2012 1994-0416 1994-0424 http://www.the-cryosphere.net/6/287/2012/tc-6-287-2012.pdf https://doaj.org/article/ab8864b25fab4984a51f8e866012a38d |
op_rights |
undefined |
op_doi |
https://doi.org/10.5194/tc-6-287-2012 |
container_title |
The Cryosphere |
container_volume |
6 |
container_issue |
2 |
container_start_page |
287 |
op_container_end_page |
299 |
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1766216492923224064 |