Source attribution of Arctic black carbon constrained by aircraft and surface measurements

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Xu, Jun-Wei, Martin, Randall W., Morrow, Andrew, Sharma, Sangeeta, Huang, Lin, Leaitch, W. Richard, Burkart, Julia, Schulz, Hannes, Zanatta, Marco, Willis, Megan D., Henze, Daven K., Lee, Colin J., Herber, Andreas B., Abbatt, Jonathan P. D.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: COPERNICUS GESELLSCHAFT MBH 2017
• Subjects: Arctic; black carbon; Siberia
• Online Access: https://epic.awi.de/id/eprint/46146/; https://epic.awi.de/id/eprint/46146/1/acp-17-11971-2017.pdf; https://www.atmos-chem-phys.net/17/11971/2017/acp-17-11971-2017.pdf; https://hdl.handle.net/10013/epic.4dd1e61d-cf07-4952-95a5-43b2c531381e; https://hdl.handle.net/

Black carbon (BC) contributes to Arctic warm- ing, yet sources of Arctic BC and their geographic con- tributions remain uncertain. We interpret a series of recent airborne (NETCARE 2015; PAMARCMiP 2009 and 2011 campaigns) and ground-based measurements (at Alert, Bar- row and Ny-Ålesund) from multiple methods (thermal, laser incandescence and light absorption) with the GEOS-Chem global chemical transport model and its adjoint to attribute the sources of Arctic BC. This is the first comparison with a chemical transport model of refractory BC (rBC) measure- ments at Alert. The springtime airborne measurements per- formed by the NETCARE campaign in 2015 and the PA- MARCMiP campaigns in 2009 and 2011 offer BC vertical profiles extending to above 6 km across the Arctic and in- clude profiles above Arctic ground monitoring stations. Our simulations with the addition of seasonally varying domes- tic heating and of gas flaring emissions are consistent with ground-based measurements of BC concentrations at Alert and Barrow in winter and spring (rRMSE < 13 %) and with airborne measurements of the BC vertical profile across the Arctic (rRMSE = 17 %) except for an underestimation in the middle troposphere (500–700 hPa). Sensitivity simulations suggest that anthropogenic emis- sions in eastern and southern Asia have the largest effect on the Arctic BC column burden both in spring (56 %) and annu ally (37 %), with the largest contribution in the middle tropo- sphere (400–700 hPa). Anthropogenic emissions from north- ern Asia contribute considerable BC (27% in spring and 43 % annually) to the lower troposphere (below 900 hPa). Biomass burning contributes 20 % to the Arctic BC column annually. At the Arctic surface, anthropogenic emissions from northern Asia (40–45 %) and eastern and southern Asia (20– 40 %) are the largest BC contributors in winter and spring, followed by Europe (16–36 %). Biomass burning from North America is the most important contributor to all stations in summer, especially at Barrow. Our adjoint simulations indicate pronounced spatial het- erogeneity in the contribution of emissions to the Arctic BC column concentrations, with noteworthy contributions from emissions in eastern China (15 %) and western Siberia (6.5 %). Although uncertain, gas flaring emissions from oil- fields in western Siberia could have a striking impact (13 %) on Arctic BC loadings in January, comparable to the total influence of continental Europe and North America (6.5 % each in January). Emissions from as far as the Indo-Gangetic Plain could have a substantial influence (6.3 % annually) on Arctic BC as well.