Impacts of meteorological parameters and emissions on decadal and interannual variations of black carbon in China for 1980-2010

We quantified the impacts of variations in meteorological parameters and emissions on decadal trends and interannual variations of black carbon (BC) in China for 1980-2010 using a global chemical transport model (GEOS-Chem) driven by the Modern Era Retrospective-analysis for Research and Applications meteorological fields. Model results reasonably captured the decadal and interannual variations of observed BC in China. From 1980 to 2010, simulated surface concentrations and tropospheric column burdens of BC increased by 0.21 μgm^-3 (29%) and by 0.29 mg m^-2 (37%), respectively, averaged over China; the corresponding all-sky direct radiative forcing at the top of the atmosphere increased by 0.35 W m^-2 (51%). Considering variations in both meteorological parameters and emissions for 1980-2010, simulated annual mean surface concentrations (column burdens) of BC were in the range of 0.7-1.0 μgm^-3 (0.8-1.1 mg m^-2) averaged over China. The associated decadal trends were 0.31 μgm^-3 decade^-1 (0.29 mg m^-2 decade^-1) in the 1980s, 0.20 (0.10) in the 1990s, and 0.16 (0.21) in the 2000s. The interannual variations were 20% to 15% (20% to 11%) for deviation from the mean, 0.068 μgm^-3 (0.069 mg m^-2) for mean absolute deviation, and 7.7% (7.1%) for absolute percent departure from the mean. Model sensitivity simulations indicated that the decadal trends of surface concentrations and column burdens of BC were mainly driven by changes in emissions, while the interannual variations were dependent on variations of both meteorological parameters and emissions.