Sensitivity and uncertainties assessment in radiative forcing due to aerosol optical properties in diverse locations in China

Aerosol optical properties play an important role in affecting direct aerosol radiative forcing (DARF). However, DARF estimation is still uncertain due to the complexity of aerosol optical properties. Therefore, in this study, the spatiotem-poral distributions of aerosol properties and their effects on DARF in China from 2004 to 2020 are investigated using the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model. The results show that the aerosol optical parameters vary greatly and change with seasonal regularity, which is greatly affected by human activities. The control variable method was employed on aerosol optical properties for better estimation of DARF. Single scattering albedo (SSA) has the greatest effect on DARF, followed by aerosol optical depth (AOD) and the asymmetric factor (ASY) among the seven examined stations in China. The average DARF decreases by 4.2 degrees Ao when the SSA increases by 0.3 degrees Ao but increases by 34.7 degrees Ao when the SSA decreases by 3 degrees Ao in mainland China. When the AOD changes from -60 to +60 degrees Ao, DARF changes from -54.7 degrees Ao to +58.4 degrees Ao. The variation in DARF is between -3 degrees Ao and +3 degrees Ao when the ASY varies from -30 degrees Ao to +30 degrees Ao. The instability in DARF resulted from the complicated and volatile nature of aerosol optical properties in the region; the aerosol optical properties are greatly affected by the aerosol types and rel-ative humidity. The results of this study have important reference significance for understanding the variation of DARF and formulating pollution prevention and control policies in the region.