The importance of Asia as a source of black carbon to the European Arctic during springtime 2013

• Published in: Atmospheric Chemistry and Physics
• Main Authors: D. Liu, B. Quennehen, E. Darbyshire, J. D. Allan, P. I. Williams, J. W. Taylor, S. J.-B. Bauguitte, M. J. Flynn, D. Lowe, M. W. Gallagher, K. N. Bower, T. W. Choularton, H. Coe
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2015
• Subjects: Physics; QC1-999; Chemistry; QD1-999; Arctic; black carbon; Sea ice
• Online Access: https://doi.org/10.5194/acp-15-11537-2015; https://doaj.org/article/a68ab05b838f49a6a86309d8b59c3aed

Black carbon aerosol (BC) deposited to the Arctic sea ice or present in the free troposphere can significantly affect the Earth's radiation budget at high latitudes yet the BC burden in these regions and the regional source contributions are poorly constrained. Aircraft measurements of aerosol composition in the European Arctic were conducted during the Aerosol–Cloud Coupling And Climate Interactions in the Arctic (ACCACIA) campaign in March 2013. Pollutant plumes were encountered throughout the lower to upper Arctic troposphere featuring enhancements in CO and aerosol mass loadings, which were chemically speciated into BC and non-refractory sulphate and organic matter. FLEXPART-WRF simulations have been performed to evaluate the likely contribution to the pollutants from regional ground sources. By combining up-to-date anthropogenic and open fire biomass burning (OBB) inventories, we have been able to compare the contributions made to the observed pollution layers from the sources of eastern/northern Asia (AS), Europe (EU) and North America (NA). Over 90 % of the contribution to the BC was shown to arise from non-OBB anthropogenic sources. AS sources were found to be the major contributor to the BC burden, increasing background BC loadings by a factor of 3–5 to 100.8 ± 48.4 ng sm −3 (in standard air m 3 at 273.15 K and 1013.25 mbar) and 55.8 ± 22.4 ng sm −3 in the middle and upper troposphere respectively. AS plumes close to the tropopause (about 7.5–8 km) were also observed, with BC concentrations ranging from 55 to 73 ng sm −3 , which will potentially have a significant radiative impact. EU sources influenced the middle troposphere with a BC mean concentration of 70.8 ± 39.1 ng sm −3 but made a minor contribution to the upper troposphere due to the relatively high latitude of the source region. The contribution of NA was shown to be much lower at all altitudes with BC mean concentration of 20 ng sm −3 . The BC transported to the Arctic is mixed with a non-BC volume fraction representing between 90–95 % of the ...