TITLE

Offsetting effects of aerosols on Arctic and global climate in the late 20th century

AUTHOR(S)
Q. Yang; Bitz, C. M.; Doherty, S. J.
PUB. DATE
November 2013
SOURCE
Atmospheric Chemistry & Physics Discussions;2013, Vol. 13 Issue 11, p30929
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
We examine the impacts of atmospheric aerosols on Arctic and global climate using a series of 20th century transient simulations from Community Climate System Model version 4 (CCSM4). We focus on the response of surface air temperature to the direct radiative forcing driven by changes in sulfate and black carbon (BC) concentrations from 1975 to 2005 and we also examine the response to sulfate, BC, and organic carbon aerosols varying at once. The direct forcing from sulfate dominates the aerosol climate effect. Globally averaged, all three aerosols produce a cooling trend of 0.015 Kdecade-1 during the period 1975-2005. In the Arctic, surface air temperature has large spatial variations in response to changes in aerosol concentrations. Over the European Arctic, aerosols induce about 0.6 K decade-1 warming which is about 1.8 K warming over the 30 yr period. This warming is triggered mainly by the reduction in sulfate and BC emissions over Europe since the 1970s and is reinforced by sea ice loss and a strengthening in atmospheric northward heat transport. Over the Siberian and North American Arctic, surface air temperature is likely influenced primarily by changes in aerosol emissions from Asia. An increase in sulfate emissions over Asia induces a large cooling while an increase in BC over Asia causes a significant warming.
ACCESSION #
93249371

 

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