CO 2 flux over young and snow-covered Arctic pack ice in winter and spring
Rare CO 2 flux measurements from Arctic pack ice show that two types of ice contribute to the release of CO 2 from the ice to the atmosphere during winter and spring: young, thin ice with a thin layer of snow and older (several weeks), thicker ice with thick snow cover. Young, thin sea ice is charac...
| Published in: | Biogeosciences |
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| Main Authors: | , , , , , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Copernicus Publications
2018
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| Subjects: | |
| Online Access: | https://doi.org/10.5194/bg-15-3331-2018 https://doaj.org/article/d18b654f6cbb4396ad9a5639f0541b76 |
| Summary: | Rare CO 2 flux measurements from Arctic pack ice show that two types of ice contribute to the release of CO 2 from the ice to the atmosphere during winter and spring: young, thin ice with a thin layer of snow and older (several weeks), thicker ice with thick snow cover. Young, thin sea ice is characterized by high salinity and high porosity, and snow-covered thick ice remains relatively warm ( > −7.5 °C) due to the insulating snow cover despite air temperatures as low as −40 °C. Therefore, brine volume fractions of these two ice types are high enough to provide favorable conditions for gas exchange between sea ice and the atmosphere even in mid-winter. Although the potential CO 2 flux from sea ice decreased due to the presence of the snow, the snow surface is still a CO 2 source to the atmosphere for low snow density and thin snow conditions. We found that young sea ice that is formed in leads without snow cover produces CO 2 fluxes an order of magnitude higher than those in snow-covered older ice (+1.0 ± 0.6 mmol C m −2 day −1 for young ice and +0.2 ± 0.2 mmol C m −2 day −1 for older ice). |
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