Effects of climate changes on dust aerosol over East Asia from RegCM3

摘要

In order to understand impacts of global warming on dust aerosol over East Asia, a regional climate model(RegCM3) coupled with a dust model is employed to simulate the present(1991-2000, following the observed concentration of the greenhouse gases) and future(2091-2100,following the A1B scenario) dust aerosol. Three experiments are performed over East Asia at a horizontal resolution of 50 km, driven by the outputs from a global model of the Model for Interdisciplinary Research on Climate(MIROC3.2_hires), two without(Exp.1 for the present and Exp.2 for the future) and one with(Exp.3 for the future) the radiative effects of dust aerosols. Effects of climate changes on dust aerosols and the feedback of radiative effects in the future are investigated by comparing differences of Exp.2 and Exp.1, Exp.3 and Exp.2, respectively. Results show that global warming will lead to the increases of dust emissions and column burden by 2% and 14% over East Asia, characterized by the increase in December-January-February-March(DJFM) and the decrease in Aprile May(AM). Similar variations are also seen in the projected frequencies of high dust emission events, showing an advanced active season of dust in the future. The net top-of-atmosphere(TOA)radiative forcing is positive over the desert source regions and negative over downwind regions, while the surface radiative forcing is negative over the domain, which will lead to a reduction of dust emissions and column burden.