Using a new technology-based and seasonally-dependent Multi-scale Emission Inventory for China (MEIC) improves the annual mean AOD simulations in eastern China by 12.9% compared with MODIS observations and 14.7% compared with MISR observations, and explains 22%-28% of the AOD low bias simulated with the default IPCC AR5 emission. Incorporating the nitrate aerosol in CAM5 with the MOSAIC scheme further improves the agreement of AOD with MODIS and MISR observations with simulated nitrate burden comparable to that of sulfate especially in winter. With the gradual increase of model resolution from 2°, 1°, 0.5°, to 0.25°, CAM5 is able to capture the finer structure of aerosol distributions and increase the magnitudes of aerosol concentrations due to better resolved collocation between aerosols and clouds important for aerosol wet scavenging.
Implications of the above improvements for aerosol direct and indirect radiative forcings are investigated. Our study suggestions that aerosol effects on East Asian climate could be significantly underestimated with current generation aerosol-climate models. Long-term measurements of aerosol composition and concentrations in different geographical regions of East Asia are urgently needed to guide the future model developments.