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
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.</p