Global three-dimensional simulation and radiative forcing of various aerosol species with GCM

A global three-dimensional transport model that can simultaneously treat main tropospheric aerosols, i.e., carbonaceous (organic and black carbons), sulfate, soil dust, and sea salt, is developed. It is coupled with an Center for Climate System Research (CCSR)/National Institute for Environmental Studies (NIES) atmospheric general circulation model (AGCM), and the meteorological field of wind, temperature, and specific humidity can be nudged by reanalysis data. Simulated results are compared with not only observations for aerosol concentrations but also the optical thickness and Ångström exponent retrieved from remote sensing data such as National Oceanic and Atmospheric Administration (NOAA)/Advanced Very High Resolution Radiometer (AVHRR) and Aerosol Robotic Network (AERONET). A general agreement is found between simulated results and observations spatially seasonally, and quantitatively. The present model is also coupled with the radiative process over both the solar and thermal regions. The annual and global mean radiative forcing by anthropogenic aerosols from fossil fuel sources is estimated to be -0.5 W m^-2 over the clear sky for the direct effect and -2.0 W m^-2 for the indirect effect.