Automatic monitoring of the effective thermal conductivity of snow in a low-Arctic shrub tundra
The effective thermal conductivity of snow, <i>k</i><sub>eff</sub>, is a critical variable which determines the temperature gradient in the snowpack and heat exchanges between the ground and the atmosphere through the snow. Its accurate knowledge is therefore required to simu...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2015-06-01
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| Series: | The Cryosphere |
| Online Access: | http://www.the-cryosphere.net/9/1265/2015/tc-9-1265-2015.pdf |
| _version_ | 1828475905700265984 |
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| author | F. Domine M. Barrere D. Sarrazin S. Morin L. Arnaud |
| author_facet | F. Domine M. Barrere D. Sarrazin S. Morin L. Arnaud |
| author_sort | F. Domine |
| collection | DOAJ |
| description | The effective thermal conductivity of snow, <i>k</i><sub>eff</sub>, is a critical variable
which determines the temperature gradient in the snowpack and heat exchanges
between the ground and the atmosphere through the snow. Its accurate
knowledge is therefore required to simulate snow metamorphism, the ground
thermal regime, permafrost stability, nutrient recycling and vegetation
growth. Yet, few data are available on the seasonal evolution of snow
thermal conductivity in the Arctic. We have deployed heated needle probes on
low-Arctic shrub tundra near Umiujaq, Quebec, (N56°34';
W76°29') and monitored automatically the evolution of <i>k</i><sub>eff</sub>
for two consecutive winters, 2012–2013 and 2013–2014, at four heights in the
snowpack. Shrubs are 20 cm high dwarf birch. Here, we develop an algorithm
for the automatic determination of <i>k</i><sub>eff</sub> from the heating curves and
obtain 404 <i>k</i><sub>eff</sub> values. We evaluate possible errors and biases
associated with the use of the heated needles. The time evolution of
<i>k</i><sub>eff</sub> is very different for both winters. This is explained by comparing
the meteorological conditions in both winters, which induced different
conditions for snow metamorphism. In particular, important melting events in
the second year increased snow hardness, impeding subsequent densification
and increase in thermal conductivity. We conclude that shrubs have very
important impacts on snow physical evolution: (1) shrubs absorb light and
facilitate snow melt under intense radiation; (2) the dense twig network of
dwarf birch prevent snow compaction, and therefore <i>k</i><sub>eff</sub> increase; (3) the
low density depth hoar that forms within shrubs collapsed in late winter,
leaving a void that was not filled by snow. |
| first_indexed | 2024-12-11T06:20:51Z |
| format | Article |
| id | doaj.art-01ff71f448c94876ad540ac2c2955be1 |
| institution | Directory Open Access Journal |
| issn | 1994-0416 1994-0424 |
| language | English |
| last_indexed | 2024-12-11T06:20:51Z |
| publishDate | 2015-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | The Cryosphere |
| spelling | doaj.art-01ff71f448c94876ad540ac2c2955be12022-12-22T01:17:50ZengCopernicus PublicationsThe Cryosphere1994-04161994-04242015-06-01931265127610.5194/tc-9-1265-2015Automatic monitoring of the effective thermal conductivity of snow in a low-Arctic shrub tundraF. Domine0M. Barrere1D. Sarrazin2S. Morin3L. Arnaud4Takuvik Joint International Laboratory, Université Laval (Canada) and CNRS-INSU (France), Pavillon Alexandre Vachon, 1045 avenue de La Médecine, Québec, QC, G1V 0A6, CanadaTakuvik Joint International Laboratory, Université Laval (Canada) and CNRS-INSU (France), Pavillon Alexandre Vachon, 1045 avenue de La Médecine, Québec, QC, G1V 0A6, CanadaCentre for Northern Studies, Université Laval, Québec, QC, CanadaMétéo-France – CNRS, CNRM-GAME UMR 3589, CEN, Grenoble, FranceLGGE, Université Grenoble Alpes and CNRS – UMR5183, 38041 Grenoble, FranceThe effective thermal conductivity of snow, <i>k</i><sub>eff</sub>, is a critical variable which determines the temperature gradient in the snowpack and heat exchanges between the ground and the atmosphere through the snow. Its accurate knowledge is therefore required to simulate snow metamorphism, the ground thermal regime, permafrost stability, nutrient recycling and vegetation growth. Yet, few data are available on the seasonal evolution of snow thermal conductivity in the Arctic. We have deployed heated needle probes on low-Arctic shrub tundra near Umiujaq, Quebec, (N56°34'; W76°29') and monitored automatically the evolution of <i>k</i><sub>eff</sub> for two consecutive winters, 2012–2013 and 2013–2014, at four heights in the snowpack. Shrubs are 20 cm high dwarf birch. Here, we develop an algorithm for the automatic determination of <i>k</i><sub>eff</sub> from the heating curves and obtain 404 <i>k</i><sub>eff</sub> values. We evaluate possible errors and biases associated with the use of the heated needles. The time evolution of <i>k</i><sub>eff</sub> is very different for both winters. This is explained by comparing the meteorological conditions in both winters, which induced different conditions for snow metamorphism. In particular, important melting events in the second year increased snow hardness, impeding subsequent densification and increase in thermal conductivity. We conclude that shrubs have very important impacts on snow physical evolution: (1) shrubs absorb light and facilitate snow melt under intense radiation; (2) the dense twig network of dwarf birch prevent snow compaction, and therefore <i>k</i><sub>eff</sub> increase; (3) the low density depth hoar that forms within shrubs collapsed in late winter, leaving a void that was not filled by snow.http://www.the-cryosphere.net/9/1265/2015/tc-9-1265-2015.pdf |
| spellingShingle | F. Domine M. Barrere D. Sarrazin S. Morin L. Arnaud Automatic monitoring of the effective thermal conductivity of snow in a low-Arctic shrub tundra The Cryosphere |
| title | Automatic monitoring of the effective thermal conductivity of snow in a low-Arctic shrub tundra |
| title_full | Automatic monitoring of the effective thermal conductivity of snow in a low-Arctic shrub tundra |
| title_fullStr | Automatic monitoring of the effective thermal conductivity of snow in a low-Arctic shrub tundra |
| title_full_unstemmed | Automatic monitoring of the effective thermal conductivity of snow in a low-Arctic shrub tundra |
| title_short | Automatic monitoring of the effective thermal conductivity of snow in a low-Arctic shrub tundra |
| title_sort | automatic monitoring of the effective thermal conductivity of snow in a low arctic shrub tundra |
| url | http://www.the-cryosphere.net/9/1265/2015/tc-9-1265-2015.pdf |
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