Aerosol impacts on the atmospheric circulation field over Asia

Aerosols affect the earth’s radiation budget directly by scattering and absorbing solar radiation. In addition, aerosols may act as cloud condensation nuclei and ice nuclei, which then modify the radiative properties of clouds. Asia constitutes the largest aerosol loading worldwide. Moreover, aerosol distributions in Asia are complicated, as they are influenced by various sources. The major source of anthropogenic aerosols, such as sulfates and carbonaceous aerosols, is fuel combustion. Fuel combustion has increased since the mid-20th century in Asia. In general, aerosols exhibit remarkable effects near sources since their atmospheric lifespans are short. This suggests that aerosol impacts on climate are large over Asia. In this study, we investigated the response of aerosols over Asia to climate using model simulations. Our results indicate that aerosols reduce solar radiation and impose negative radiative forcing near the surface. Because cloud change is complicated, aerosols change cloud radiative properties, with positive or negative radiative forcing occurring near the surface. Changes in the radiation budget lead to temperature changes, which in turn influence precipitation.