%ABreider, Thomas [John A. Paulson School of Engineering and Applied Sciences Harvard University Cambridge Massachusetts USA]%ABreider, Thomas [John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge Massachusetts USA]%AMickley, Loretta [John A. Paulson School of Engineering and Applied Sciences Harvard University Cambridge Massachusetts USA]%AMickley, Loretta [John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge Massachusetts USA]%AJacob, Daniel [John A. Paulson School of Engineering and Applied Sciences Harvard University Cambridge Massachusetts USA]%AJacob, Daniel [John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge Massachusetts USA]%AGe, Cui [Center for Global and Regional Environmental Research University of Iowa Iowa City Iowa USA, Department of Chemical and Biochemical Engineering University of Iowa Iowa City Iowa USA]%AGe, Cui [Center for Global and Regional Environmental Research; University of Iowa; Iowa City Iowa USA; Department of Chemical and Biochemical Engineering; University of Iowa; Iowa City Iowa USA]%AWang, Jun [Center for Global and Regional Environmental Research; University of Iowa; Iowa City Iowa USA; Department of Chemical and Biochemical Engineering; University of Iowa; Iowa City Iowa USA]%AWang, Jun [Center for Global and Regional Environmental Research University of Iowa Iowa City Iowa USA, Department of Chemical and Biochemical Engineering University of Iowa Iowa City Iowa USA]%APayer Sulprizio, Melissa [John A. Paulson School of Engineering and Applied Sciences; Harvard University; Cambridge Massachusetts USA]%APayer Sulprizio, Melissa [John A. Paulson School of Engineering and Applied Sciences Harvard University Cambridge Massachusetts USA]%ACroft, Betty [Department of Physics and Atmospheric Science Dalhousie University Halifax Nova Scotia Canada]%ACroft, Betty [Department of Physics and Atmospheric Science; Dalhousie University; Halifax Nova Scotia Canada]%ARidley, David [Department of Civil and Environmental Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA]%ARidley, David [Department of Civil and Environmental Engineering; Massachusetts Institute of Technology; Cambridge Massachusetts USA]%AMcConnell, Joseph [Desert Research Institute Reno Nevada USA]%AMcConnell, Joseph [Desert Research Institute; Reno Nevada USA]%ASharma, Sangeeta [Atmospheric Science and Technology Directorate, Climate Research Division; Environment and Climate Change Canada; Toronto Ontario Canada]%ASharma, Sangeeta [Atmospheric Science and Technology Directorate, Climate Research Division Environment and Climate Change Canada Toronto Ontario Canada]%AHusain, Liaquat [Atmospheric Sciences Research Center State University of New York at Albany Albany New York USA]%AHusain, Liaquat [Atmospheric Sciences Research Center; State University of New York at Albany; Albany New York USA]%ADutkiewicz, Vincent [Atmospheric Sciences Research Center; State University of New York at Albany; Albany New York USA]%ADutkiewicz, Vincent [Atmospheric Sciences Research Center State University of New York at Albany Albany New York USA]%AEleftheriadis, Konstantinos [Environmental Radioactivity Laboratory; INRaSTES, NCSR Demokritos; Athens Greece]%AEleftheriadis, Konstantinos [Environmental Radioactivity Laboratory INRaSTES, NCSR Demokritos Athens Greece]%ASkov, Henrik [Arctic Research Center, Department of Environmental Science Aarhus University Roskilde Denmark]%ASkov, Henrik [Arctic Research Center, Department of Environmental Science; Aarhus University; Roskilde Denmark]%AHopke, Phillip [Center for Air Resources Engineering and Science; Clarkson University; Potsdam New York USA]%AHopke, Phillip [Center for Air Resources Engineering and Science Clarkson University Potsdam New York USA]%BJournal Name: Journal of Geophysical Research: Atmospheres; Journal Volume: 122; Journal Issue: 6; Related Information: CHORUS Timestamp: 2023-09-16 08:58:42 %D2017%IDOI PREFIX: 10.1029 %JJournal Name: Journal of Geophysical Research: Atmospheres; Journal Volume: 122; Journal Issue: 6; Related Information: CHORUS Timestamp: 2023-09-16 08:58:42 %K %MOSTI ID: 10034017 %PMedium: X %TMultidecadal trends in aerosol radiative forcing over the Arctic: Contribution of changes in anthropogenic aerosol to Arctic warming since 1980 %XAbstract

Arctic observations show large decreases in the concentrations of sulfate and black carbon (BC) aerosols since the early 1980s. These near‐term climate‐forcing pollutants perturb the radiative balance of the atmosphere and may have played an important role in recent Arctic warming. We use the GEOS‐Chem global chemical transport model to construct a 3‐D representation of Arctic aerosols that is generally consistent with observations and their trends from 1980 to 2010. Observations at Arctic surface sites show significant decreases in sulfate and BC mass concentrations of 2–3% per year. We find that anthropogenic aerosols yield a negative forcing over the Arctic, with an average 2005–2010 Arctic shortwave radiative forcing (RF) of −0.19 ± 0.05 W m−2at the top of atmosphere (TOA). Anthropogenic sulfate in our study yields more strongly negative forcings over the Arctic troposphere in spring (−1.17 ± 0.10 W m−2) than previously reported. From 1980 to 2010, TOA negative RF by Arctic aerosol declined, from −0.67 ± 0.06 W m−2to −0.19 ± 0.05 W m−2, yielding a net TOA RF of +0.48 ± 0.06 W m−2. The net positive RF is due almost entirely to decreases in anthropogenic sulfate loading over the Arctic. We estimate that 1980–2010 trends in aerosol‐radiation interactions over the Arctic and Northern Hemisphere midlatitudes have contributed a net warming at the Arctic surface of +0.27 ± 0.04 K, roughly one quarter of the observed warming. Our study does not consider BC emissions from gas flaring nor the regional climate response to aerosol‐cloud interactions or BC deposition on snow.

%0Journal Article