| In this paper,the numerical simulation of WRF-Chem and the actual observation data are used to analyze the process of heavy pollution in the autumn and winter of 2016 in Xuzhou City.The process of heavy pollution in Xuzhou City is analyzed.HYSPLIT and scenario analysis were used to analyze the source of pollutants and calculate the simulation accuracy of WRF-Chem model for Xuzhou pollution.Get the following conclusion:(1)From November 2016 to January 2017 the correlation coefficient of daily PM2.5 concentration was 0.69,NMB was-5.37%,NME was 30.86%,the observed average was 103.39 ? g/m3,The simulated average is 97.84 ? g/m3.The correlation coefficient of hourly PM2.5 concentration is 0.47?0.68.There is a phenomenon that the simulated value of PM2.5 concentration in the heavy pollution maintenance period is lower than the actual observation value.(2)The adverse weather conditions in autumn and winter are weak low pressure,weak high pressure,the center of high pressure at ground and straight west wind,southwest wind,disturbance small slot at the height of 500hPa.Favorable weather situation are the ground field into the sea low pressure,the north to strengthen the high pressure,northwest air at 500hPa.Xuzhou is located in the back of the low pressure,high pressure front,high pressure rear,the strong north wind,east wind conducive to pollution diffusion.The feature of heavy pollution is the boundary layer is low,the wind speed is 0.7m/s?1.1m/s,and the relative humidity is 74%?83%.Xuzhou pollution space characteristics for the urban concentration is higher than the surrounding counties.(3)The contribution rate of exogenous sources of 11 sites was 68%?80%and the concentration was 79.2?90.0 ? g/m3.The regional transportation in autumn and winter had an important effect on PM2.5 concentration in Xuzhou.The average contribution rate of Jiangsu Province is 26.48%,19.21%in Shandong Province,15.65%in Anhui Province and 9.2%in Henan Province. |
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