Aerosol radiative forcing over East Asia determined from ground-based sunphotometry measurements

Mean radiative forcing efficiencies (${\Delta}$F/${\Delta}{\tau}_{0.5}$) over East Asia range from -65 to -95 W m$^{-2}$ at the surface while -20 to -40 W m$^{-2}$ at TOA under clear-sky conditions. These aerosol direct radiative forcings over East Asia are similar to other experimental results for different regions, i.e., the Indian Ocean Experiment (INDOEX) and the Tropospheric Aerosol Radiative Forcing Observational Experiment (TARFOX), from which radiative forcing efficiencies of -75 Wm$^{-2}$ and -70 Wm$^{-2}$ for the Indian Ocean and the East Coast of the United States are reported. Nevertheless, the differences in aerosol parameters and relatively large STD values with regard to spatiotemporal variations suggest that the impact of aerosol on ARF over East Asia is more significant than previously recognized for other regions and should be continuously observed to determine the relation between increasing aerosols and associated radiative forcings in the region.