Contribution of different aerosol models to short-wave direct radiation effects under clear and haze conditions

Aerosol absorption and scattering notably influence the atmospheric radiative balance. Significant uncertainties persist regarding the impact of aerosol models on aerosol radiative forcing (ARF) under distinct atmospheric conditions. The effects of various aerosol models on ARF under clear and haze conditions are analyzed utilizing MODIS data, combined with observations from Beijing, and the 6S (Second Simulation of the Satellite Signal in the Solar Spectrum) for simulations. Results showed that ARF at the surface (ARF-SFC) and top of the atmosphere (ARF-TOA) registered negative values on clear and hazy days. On hazy days, the desert model demonstrated enhanced cooling at TOA, while the urban model showed intensified surface cooling. Hazy conditions amplified ARF-TOA by 57%, 54%, and 61% for desert, urban, and continental models respectively, relative to clear days, with corresponding ARF-SFC increases of 57%, 54%, and 56%. Aerosol radiative forcing efficiency at TOA generally exhibited greater values in winter than in summer. Black carbon (BC) radiative forcing simulations using the three-component method showed positive values at TOA and negative values at the surface. During hazy days, BC intensified upper-atmosphere heating and surface cooling effects. This research will lay the scientific foundation for reducing uncertainty in ARF estimates and developing effective environmental strategies.