Dark Warming

As the Arctic sea ice thins and ultimately disappears in a warming climate, its insulating power decreases. This causes the surface air temperature to approach the temperature of the relatively warm ocean water below the ice. The resulting increases in air temperature, water vapor, and cloudiness le...

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Bibliographic Details
Published inJournal of climate Vol. 29; no. 2; pp. 705 - 719
Main Authors Burt, Melissa A., Randall, David A., Branson, Mark D.
Format Journal Article
LanguageEnglish
Published Boston American Meteorological Society 01.01.2016
Subjects
Air temperature
Arctic sea ice
Atmosphere
Brackish
Climate change
Cloud cover
Cloudiness
Clouds
Downwelling
Evaporation
Feedback
Global warming
Ice
Insulating materials
Insulation
Long wave radiation
Marine
Meteorology
Observational studies
Oceans
Radiation
Sea ice
Sea level
Sea level pressure
Seawater
Simulation
Solar radiation
Summer
Surface temperature
Surface wind
Surface-air temperature relationships
Water vapor
Water vapour
Wind speed
Winter
Winter monsoon
Arctic Ocean
Arctic region
PN, Arctic Ocean
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Summary:As the Arctic sea ice thins and ultimately disappears in a warming climate, its insulating power decreases. This causes the surface air temperature to approach the temperature of the relatively warm ocean water below the ice. The resulting increases in air temperature, water vapor, and cloudiness lead to an increase in the surface downwelling longwave radiation (DLR), which enables a further thinning of the ice. This positive ice–insulation feedback operates mainly in the autumn and winter. A climate change simulation with the Community Earth System Model shows that, averaged over the year, the increase in Arctic DLR is 3 times stronger than the increase in Arctic absorbed solar radiation at the surface. The warming of the surface air over the Arctic Ocean during fall and winter creates a strong thermal contrast with the colder surrounding continents. Sea level pressure falls over the Arctic Ocean, and the high-latitude circulation reorganizes into a shallow “winter monsoon.” The resulting increase in surface wind speed promotes stronger surface evaporation and higher humidity over portions of the Arctic Ocean, thus reinforcing the ice–insulation feedback.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
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ISSN:0894-8755
1520-0442
DOI:10.1175/JCLI-D-15-0147.1