The Simulation And Analysis Of Aerosol Radiative Feedback Efrects During The Atmospheric Pollution Process

The WRF-Chem model coupled with the FINN biomass burning date are used to simulate an air pollution episode, and thus the impact of aerosol radiative effect on meteorological elements and air pollutant concentrations are investigated by different numerical experiments, the main conclusions are as follows:(1) Overall, the model shows a good performance in simulating the average temperature of sites, and the mean bias is1.66℃. The warm biases of simulated average temperature lead to the negative biases of average relative humidity at most sites, the mean bias is-6.74%. The simulated average wind speed is higher than the observed results at each site, the mean bias is1.37m/s. The lower emission of anthropogenic sources results in the lower simulated air pollution index in most cities.(2) A closer inspection of simulation results has conducted in Nanjing. Although the simulated wind speeds are close to the observed ones, but the significantly increasing wind speeds are simulated with time passing. The change trends of simulated temperature are in accordance with the observations, and the positions of their peak and valley values are relatively consistent, with a correlation coefficient of0.9021. The change trends of observed and simulated ozone concentrations are in good agreement, but both the observed and simulated nitrogen dioxide concentrations have a great fluctuation.(3) In the process of air pollution caused by biomass burning, both aerosol direct effect (including the semi-direct) and indirect effect will result in a decrease of near surface temperature, planetary boundary layer height and near surface wind speed which are not conducive to the diffusion of air pollution. Therefore, the aerosol radiative feedback effects will further aggravate the pollution over the air pollution areas.(4) The aerosol total radiative effects increase the concentrations of PM10near the surface, and the distributions of differences between the extinction coefficients are coincident with the distributions of differences between PM10concentrations. Aerosol direct and semi-direct effect increase the concentrations of NOx near the surface at biomass burning areas, while indirect effect decrease the concentrations of NOx at part of biomass burning areas. Due to the weakening surface solar radiation, the significant reduction of O3concentrations is found in downwind areas of biomass burning.(5) In Nanjing, surface temperature decreases by0.79℃, relative humidity increases by 5.71%, surface wind speed increases by0.06m/s, PM10concentration increases by11.88μg/m3, NOx concentration decreases by0.86ppb and O3concentration decreases by1.87ppb when considering the aerosol total radiative effects.