Analysis of Optical Properties and Radiative Forcing of Different Aerosol Types in Wuhan ^†

The optical and radiative properties of aerosols are governed by their types. In this paper, the optical and radiative properties of different aerosol types in Wuhan, China, have been inverted and investigated using the collected PM_2.5 samples. The results show that PM_2.5 (average mass concentration about 31.25 μg/m³) is mainly contributed by sulfate (SO₄) and organic carbon (OC) (22% and 52%, respectively), while aerosol optical depth (AOD, average about 0.28) is mainly contributed by SO₄ and black carbon (EC) (22% and 19%, respectively). SO4 and nitrate (NO₃) have a negative radiative forcing at the top of the atmosphere (TOA) and a cooling effect, while OC and EC have a positive radiative forcing and a heating effect. Moreover, EC has the most significant effect on the radiative forcing in Wuhan, contributing up to 61% and 73% at the bottom of the atmosphere (BOA) and atmosphere (ATM), respectively, while contributing up to 75% to the atmospheric heating rate (about 1~2 K/day).