Potentiality of Aerosols in Changing the Precipitation Field in Asia

Abstract

We performed an experiment under ideal conditions using a general circulation model and found that aerosols can play an important role in altering the precipitation in Asia. Emissions of anthropogenic aerosols are increasing in Asia, affecting the global and regional climates through their direct and indirect effects. However, the link between aerosol loading and climate change due to these effects is still difficult to understand. The present study was based on a three-dimensional aerosol transport model coupled with a mixed-layer ocean model; it focused on the effects of anthropogenic aerosols on boreal summer precipitation over Asia. We investigated these effects by taking differences between the results of equilibrium runs with pre-industrial and current fossil fuel burning aerosol (FFA) conditions. In this model simulation, aerosol loading changed the circulation field through changes in the radiation budget. The indirect effects of aerosols include not only the first and second indirect effects but also the effects of these changes. Our results show that an increase in anthropogenic aerosols reduces precipitation due to weaker convection with both surface cooling and sea surface temperature (SST) changes. This mechanism is the most effective way for aerosols to impact precipitation in this model simulation.