The radiative forcing caused by aerosol-cloud interaction (ACI) is one of the most critical factors that lead to climate research uncertainty. In East China and the adjacent sea areas, the severe air pollution makes the ACI effect stronger than in other regions, but few observational studies focus on the effect of different aerosol components. This study estimated the shortwave radiation effect at the top of the atmosphere (TOA) caused by the interaction between the increased aerosol and the warm liquid cloud in East China and the East China Sea by applying the multiple linear regression into two ACI effect calculating methods proposed by Quaas et al. (2008; Method 1) and Chen et al. (2014; Method 2). Four aerosol components, black carbon (BC), dust (DU), organic carbon (OC), and sulfate (SU), are included in this research. The total ACI radiation effect of the four aerosol components is -12.08 +/- 4.63 W m(-2) in Method 1 and - 9.25 +/- 10.44 W m(-2) in Method 2, respectively, indicating a cooling effect to the planet. The divergence in the two methods is probably because the higher aerosol loading increases the cloud property retrieval deviation, and the cloud droplet spectral dispersion is neglected in Method 1. The effect of different aerosol components has significant diversity, with OC and SU have a cooling effect, DU has a heating effect, and BC shows an obvious geographical distinction. Further analysis suggests that under a similar aerosol optical depth (AOD), the areas with high relative humidity (RH) and low-tropospheric stability (LTS) have a more significant cooling effect due to the suppression of droplet evaporation and entrainment. Regions with higher average cloud top height also have a stronger cooling effect, especially for BC and SU. The possible reason is that high cloud altitude reduces the aerosol concentration within the cloud, further alleviates the heating effect of absorbing aerosols, and reduces the cloud droplet evaporation caused by the over much cloud condensation nuclei. This research contributes to a better understanding of the aerosolcloud radiative effect and its mechanism in East China and the East China Sea.

This study examines the mass distributions and direct and semi-direct effects of different Anthropogenic Aerosols (AAs) [i.e. sulphate, Black Carbon (BC), Organic Carbon (OC) and all together (SBO)] over South Africa using the 12 year runs of the Regional Climate Model (RegCM4). The maximum burden and Surface Radiative Forcing (SRF) values are found over AA source regions: up to 9mg m(-2) [-12W m(-2)] for sulphate and 12.1mg m(-2) [-14W m(-2)] for SBO during austral summer, as well as, up to 0.85mg m(-2) [-2W m(-2)] for BC and 2.2mg m(-2) [-0.68W m(-2)] for OC during austral winter. Contrary to sulphate, both BC and OC aerosols reduce incoming solar radiation reaching the ground via enhancing shortwave radiative heating in the atmosphere. The climatic feedback caused by AAs resulted in changes in background aerosol concentrations. As a result of this and other processes of the climate system, the climatic effects of AAs were also found in remote areas away from the main AA loading zones. However, in terms of statistical significance, the climatic influences of AAs are more prominent in the vicinity of their source regions. The overall feedback of the climate system to the radiative effects of AAs resulted in both positive and negative changes to the Net Atmospheric radiative Heating Rate (NAHR). Areas that experience a reduction in NAHR exhibited an increase in Cloud Cover (CC). During the NAHR enhancement, CC over arid areas decreased; while CC over the wet/semi-wet regions increased. The changes in Surface Temperature (ST) and sensible heat flux are more closely correlated with the CC change than SRF of AAs. Furthermore, decreases or increases in ST, respectively, lead to reductions or enhancements in boundary layer height and the vice versa in surface pressure. Overall, the results suggest that the feedback of cloud fields has a far-reaching role in moderating other climatic anomalies.