Distribution and direct radiative forcing of black carbon aerosols over Korean Peninsula

Regional air quality modelling was used to simulate the distribution of BC aerosol over the Korean Peninsula for four mid-season months of 2009. Compared to ground-based and satellite observations, the model underestimated the average BC burden significantly, which might be attributed to inaccuracy in BC emissions inventories partly due to the neglect of the emissions from biomass burning although it is not possible to rule out inaccurate prediction of meteorology. The model-estimated monthly average BC burden was highest in winter because of the largest emission. When the BC burden was divided by the monthly emission factor, the adjusted BC burden was much higher in spring and fall than in winter and summer due to strong influence of Chinese source conveyed by westerly wind prevailing in spring and fall. Both long-range transport and local sources were shown to contribute to atmospheric BC over the Korean Peninsula. Urban areas were influenced more by local sources while the effect of long-range transport was higher in remote areas. Based on the model simulations, the direct radiative forcing (DRF) of BC was estimated to be 0.1–1.8 W m−2 over the Korean Peninsula with the domain-average value of 0.39 W m−2. Accounting for the model underestimation of absorbing aerosol optical depth by BC by 48% compared to measured monthly averages due to the underestimated emissions inventories, the adjusted average DRF is 0.75 W m−2.

► Black carbon distribution over Korean Peninsula for four seasons was simulated. ► High trans-boundary transport was predicted in spring and in autumn. ► Model underestimated black carbon concentration due to inaccuracy in emissions. ► Both long-range transport and local sources contribute over Korean peninsula. ► Direct forcing of black carbon is larger than that of methane over Korean Peninsula.