Application Of Real Time Analysis Based On Community Multiscale Air Quality Modeling System During The G20 Summit

In recent years,the problem of air pollution in China has been receiving wild attention from different fields,in order to improve the air quality,the government has adopted sorts of control measures,among which the short-term ones always appeared in important activities,draw a lot of attention because of the social influence.In consideration of scientific decision-making,the real time analysis is important.This article brought in community multiscale air quality modeling system CMAQ to make up the second generation real time forecasting modeling system WRF-CMAQ,with the help of WRF-CMAQ,we carried on real time analysis to the short-term control measures during the G20 summit,the results from which could be useful to decision-making.The results of real time evaluation showed that the share rate of Hangzhou?Zhejiang?Shanghai?Jiangsu?Anhui in Hangzhou PM2.5concentration decrease was 59.2%?31.4%?1.3%?3.6%?4.5%respectively,the influence of other provinces was decided by the local transport,the conitinuous strong local transport made the share rate of other provinces reach up to 10%,which means the strict control measures were carried out in the whole YRD.The share rate of Zhejiang power plant?industrial combustion?Metal&Cement?other industry?other trade in Hangzhou PM2.5 concentration decrease was 5.4%?13.5%?55.3%?20%?5.8%,the share rate of Zhejiang power plant reduced to less than 3%from 8.29,whch means the closer the G20 summit got,the tougher the control measures became.The regional and industry-classified share rate in Hangzhou PM2.5 concentration decrease obtained from real time evaluation inosculated with the results from post-avalution,the correlation index reached up to 0.85?0.98 respectively,which means with the knowledge of specific control measures,the results from real time evaluation are convincing,the accuracy is decided by the model itself.We also carried on real time forecasting to the Hangzhou PM2.5 concentration during the G20 summit with the help of control measure prediction,the forecasting results inosculated with the monitoring data at the peaks and vallies,however,we underestimate the PM2.5 concentration,it was possibly because of the over estimate of the effect caused by the control measures.We only carried on 3-day forecasting at a time,the bias was huge,the forecasting results inosculated with the monitoring data except of that point,the correlation index was 0.35,which means on the one hand the results was convincing,and on the other hand,2 day was the limitation of real time forecasting.