Investigating the role of dust in ice nucleation within clouds and further effects on the regional weather system over East Asia – Part 2: modification of the weather system

Abstract. An updated version of the Weather Research and Forecast model coupled with Chemistry (WRF-Chem) was applied to quantify and investigate the full effects of dust on the meteorological field over East Asia during March and April 2012. The performances of the model in simulating the shortwave and longwave radiation, surface temperature, and precipitation over East Asia are improved by incorporating the effects of dust in the simulations. The radiative forcing induced by the direct radiative effect of dust is greater than that by the dust-enhanced cloud radiative effect. The indirect effects of dust result in a substantial increase in ice clouds at the middle to upper troposphere and a reduction in liquid clouds at the low to mid-troposphere. The radiative forcing combined with the redistribution of atmospheric water vapor results in an overall decrease in near-surface temperature and an increase in temperature at the middle to upper troposphere over East Asia, leading to an inhibition of atmospheric instability over most land areas, but an enhancement of atmospheric instability over south China. Upon considering the effects of dust, convective precipitation exhibits an inhibition over areas from central to east China and an enhancement over south China. Meanwhile, the locations of non-convective precipitation are shifted due to the perturbation of cloud water path. The total amount of precipitation over East Asia remains unchanged; however, the precipitation locations are shifted. The precipitation can be enhanced or inhibited by up to 20 % at particular areas.