Numerical Simulation Of The Impact Of Dust Aerosol On Convective Cloud Precipitation In Xinjian

As one of the main components of atmospheric aerosols,dust aerosol can affect the radiation balance of the earth by absorbing and scattering solar radiation.It can also participate in cloud and precipitation processes by acting as cloud condensation nuclei(CCN)or ice nuclei(IN).In order to study the influence of dust aerosol layer on cloud and precipitation,this paper simulated a convective process in Aksu,Xinjiang,using the high-resolution Weather Research and Forecasting(WRF)model coupled with a spectral bin microphysics(SBM)scheme.The effects of the aerosol layer on cloud dynamic,microphysics and precipitation processes at different heights and heating rates are discussed respectively.The main results of the research are as follows:1)when the dust aerosol is in the lower layer,cloud condensation nuclei(CCN)has a more obvious effect on the cloud microphysical process.As CCN increases,cloud droplet concentration increases,cloud droplet effective radius decreases,and precipitation delays.When the dust aerosol is higher,ice nuclei(IN)has a more obvious influence on the cloud microphysical process.With the increase of IN concentration,the number of ice crystals increases,the growth process of snow,graupel and hail is enhanced,the number of ice particles involved in the melting process increases,and the rainrate increases.2)When dust aerosol layers with different heating effects,which are located in the middle and upper troposphere,which act as CCN and IN at the same time,the atmospheric temperature at the height of the dust layer increases,the saturated water vapor pressure increases,and the relative humidity decreases,the condensation process of water vapor is inhibited.The effective radius of droplets decreases,more small-size ice phrase particles promote the formation of snow and graupel,while the production of hail is inhibited.The rainrate increases after taking into account the heating effect,which promotes the melting process of ice particles and leads to earlier rainfall.3)The effect of acting as CCN and IN of dust aerosols mainly increased vertical velocity,promoted the updraft development,delayed precipitation and enhanced rainrate fall,while the direct effect effect inhibited updraft development,advanced precipitation andenhanced rainrate.When the direct effect and effect of acting as CCN and IN are considered at the sametime,the direct effect has more influence on the precipitation process of the cloud,which mainly inhibits the updraft development but advances the rainfall.