第九届青年地学论坛

Fire emissions in Southeast Asia transported to southern China every spring (March-May), influencing not only the air quality but also the weather and climate. However, the multi-year variations and magnitude of this impact on aerosol radiation forcing in southern Chinaremain unclear. Here, we quantified the multi-year contributions of fire emissions in Indo-China Peninsula (ICP) region to aerosol radiation forcing in the various southern Chinese provinces during the fire season (March–May) of 2013–2019 combining the GEOS-Chem chemical transport model and the Column Radiation Model (CRM) model simulations. The fire emissions over the ICP region were found to increase the aerosol optical depth (AOD) value by 0.1 (15%) and reduce the single scattering albedo (SSA) in three southern regions of China (YN, GX, and GD from west to east), owing to increases in the proportions of black carbon (BC, 0.4%±0.1%) and organic carbon (OC, 3.0%±0.9%) within the aerosol compositions. The transported smoke aerosols cooled surface but heated the atmosphere in the southern China regions, with the largest mean reduction of -5 Wm^-2 (-3%) in surface shortwave radiation forcing and the maximum daily contributions of about -15 Wm^-2 (-15%) to the atmosphere radiation forcing in the GX region, followed by the GD and YN regions. The impacts of ICP fire emissions on aerosol optical and radiative parameters declined during 2013–2019, with the highest rate of 0.393±0.478 Wm^-2yr^-1 in the GX for the shortwave radiation forcing in the atmosphere. Besides, their yearly changes in the contribution were consistent with the annual fire emissions in the ICP region. Such strong radiative perturbations of ICP fire emissions were expected to influence regional meteorology in southern China and should be considered in the climate simulations.

Smoke aerosol, Aerosol radiation forcing, Southeast Asia, Southern China