Symptoms of Arctic Amplification observed in Ny-Ålesund


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Marion.Maturilli [ at ] awi.de

Abstract

Over the recent decades, temperature increase in the Arctic has been almost twice as large as the global average. This amplification of global warming is attributed to various feedback mechanisms present in the Arctic environment. Some processes are locally confined to the diminishing sea ice cover of the Arctic ocean, particularly the sea ice – albedo effect during polar day. Other amplifying processes related to the increasing open water surface of the Arctic ocean include e.g. the increasing heat flux from the ocean to the atmosphere. The resulting latent heat flux and augmenting evaporation contribute to an increasing atmospheric moisture content, which affects the longwave downward radiation directly or via changing cloud microphysics. Furthermore, atmospheric moisture and heat are more frequently advected from lower latitudes into the Arctic in relation to changes in the atmospheric circulation. During the dark period of polar night, the Arctic warming trend is not homogenously distributed over the polar cap, but occurs strongest at the surface in the Barents / Kara Seas and in the free troposphere of the Arctic North Atlantic sector. Thus, Svalbard is located in a key region of climate change. Observations from Ny-Ålesund at the west coast of the Svalbard archipelago show an annual temperature increase of 1.4 K per decade since the 1990s, with an average temperature that by now exceeds those observed during the early Arctic warming period in the 1920 to 1940s. The recent winter warming is even twice as high, and is accompanied by an increase in atmospheric moisture. Surface radiation observations in winter further indicate a change in cloudiness along with an increase in net longwave radiation. Although the winter warming is bottom-amplified, radiosonde observations show that the increasing temperature signal occurs over the entire troposphere. Indeed, part of the Svalbard winter warming is associated with enhanced warm and moist air advection in the free troposphere caused by increased cyclonic activity related to changes in atmospheric circulation patterns. The various processes contributing to Arctic amplification of climate warming link the local observations from Ny-Ålesund with processes occurring both in the Arctic and in the northern hemispheric mid-latitudes.



Item Type
Conference (Invited talk)
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Primary Division
Programs
Primary Topic
Research Networks
Peer revision
Peer-reviewed
Publication Status
Published
Event Details
Svalbard Science Conference, 06 Nov 2017 - 08 Nov 2017, Oslo.
Eprint ID
45917
Cite as
Maturilli, M. , Dahlke, S. , Kayser, M. , Boike, J. and Fischer, P. (2017): Symptoms of Arctic Amplification observed in Ny-Ålesund , Svalbard Science Conference, Oslo, 6 November 2017 - 8 November 2017 .


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