利用WRF/Chem(Weather Research and Forecasting Model coupled with Chemistry)模拟了2013年12月华东地区一次雾、霾事件气溶胶辐射反馈效应对气象场和大气质量的影响。通过3个不同气溶胶浓度设置的试验区分气溶胶浓度不同辐射效应的影响。比较不同试验得出,本次雾、霾过程中,不论是气溶胶直接、半直接辐射效应还是间接效应均使污染地区短波辐射减少、2 m气温下降、大气边界层高度降低,不利于水汽与污染物的扩散,空气污染进一步加重,雾结构进一步稳定,并使雾的持续时间延长,发展高度更高;对于化学场来说,气溶胶直接、半直接辐射效应使污染地区PM(2.5)浓度增大、消光系数增大、氮氧化物浓度增大,臭氧浓度降低;间接辐射效应使PM(2.5)浓度和消光系数进一步增大,氮氧化物、臭氧浓度降低。综上所述,气溶胶辐射效应能使大气污染加重,并利于雾的发生、发展。
The effects of aerosol-radiation feedback on meteorology and air quality over eastern China during a severe smog event in December 2013 are simulated using the fully coupled online Weather Research and Forecasting/Chemistry model.Three simulation scenarios that include different aerosol configurations are applied to distinguish aerosol radiative effects.Results of these experiments indicate that the simulated shortwave radiation at the surface,2 m temperature and planetary boundary layer(PBL)height all reduce over the polluted areas during the smog event due to direct,semi-direct,and indirect radiation effects of aerosols.A lower PBL height is unfavorable for the dispersion of water vapor and pollutants,which makes the fog structure more stable and deteriorates the smog event.Furthermore,the aerosol radiation effects(direct,semi-direct and indirect effect)prolong the duration of the smog event and the pollutants can reach higher levels.Looking at the chemical species,it is found that the aerosol direct and semi-direct radiation effects lead to increases in PM2.5concentration,extinction coefficients,NOx concentration and decreases in O3concentration;meanwhile,the aerosol indirect radiation effect further increases PM2.5concentrations and extinction coefficient but decreases NOxand O3 concentration.In general,the aerosol radiative effects deteriorate the air pollution event by promoting the development of smog.