Dust modeling over East Asia during the summer of 2010 using the WRF-Chem model

An intense summer dust storm over East Asia during June 24-27, 2010, was systematically analyzed based on the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and a variety of in situ measurements and satellite retrievals. The results showed that the WRF-Chem model captures the spatial and temporal distributions of meteorological factors and dust aerosol in summer over East Asia well. This summer dust storm is initiated by the approach of a transverse trough in the northwestern Xinjiang. Because of the passage of the cutoff-low, a large amount of cold air is transported southward and further enhanced by the narrow valleys of the Altai and Tianshan Mountains, which results in higher wind speeds and huge dust emissions over the Taklimakan Desert (TD). Dust emission fluxes over the TD areas are high as 54 µg m−2 s−1 on June 25. The dust aerosol from the TD then sweeps across Inner Mongolia, Ningxia and Mongolia, and some are also transported eastward to Beijing, Tianjin, Hebei, and even South Korea and Japan. The simulations further show that summer dust over East Asia exerts an important influence on the radiation budget in the Earth-atmosphere system. Dust heats the atmosphere at a maximum heating rate of 0.14 K day−1, effectively changing the vertical stability of the atmosphere and affecting climate change at regional and even global scales. The average direct radiative forcing induced by dust particles over the TD at all-sky is −6.0, −16.8 and 10.8 W m−2 at the top of the atmosphere, the surface, and in the atmosphere, respectively. The discussion about radiative forcing induced by summer dust provides confidence for future investigation of summer dust impact on cloud properties and precipitation efficiency in the eastern China.