Test and Correction of CUACE Model in Air Quality Forecast in the Qinghai-Tibet Plateau:A Case Study of Xining City

Based on the data of national monitoring points of air pollution control in Xining from 2015 to 2017,the air quality prediction of CUACE model in Xining was tested by using the method of national environmental meteorological numerical model prediction quality inspection and evaluation.The results show that the prediction accuracy of the CAUCE model for the primary pollutants in Xining region during 2015-2017 was generally higher in the winter half year,and the maximum appeared in November 2016.The prediction accuracy in 24,48 and 72 h was more than 70%.The prediction accuracy of the model in the summer half year was low.The primary pollutants in Xining area were PM_(10),PM_(2.5),O_(3),NO_(2) and CO.The prediction accuracy of PM_(10) was the highest,followed by PM_(2.5),while that of O 3 was the lowest.TS score of 24-hour forecast of light pollution was greater than 0 in the winter half year,and it was the highest in December when the unreported rate was also the highest;the empty report rate existed all year round,and was the highest from May to June.Forecast deviation was greater than 0 in the winter half year,and the maximum appeared in January.The 48-hour and 72-hour model forecast were consistent with the 24-hour forecast.The forecast effect of the model on sudden pollution weather was poor,and moderate pollution,severe pollution,and serious pollution weather occurred less frequently in Xining region,so there was fewer model forecast of this kind of pollution.Besides,among the 24-,48-and 72-hour forecast values of the model,there were many empty reports of this kind of pollution,and the empty report rate was high.

Modeling study on the roles of the deposition and transport of PM_(2.5) in air quality changes over central-eastern China

The role of PM_(2.5)(particles with aerodynamic diameters≤_(2.5)μm)deposition in air quality changes over China remains unclear.By using the three-year(2013,2015,and 2017)simulation results of the WRF/CUACE v1.0 model from a previous work(Zhang et al.,2021),a non-linear relationship between the deposition of PM_(2.5)and anthropogenic emissions over central-eastern China in cold seasons as well as in different life stages of haze events was unraveled.PM_(2.5)deposition is spatially distributed differently from PM_(2.5)concentrations and anthropogenic emissions over China.The North China Plain(NCP)is typically characterized by higher anthropogenic emissions compared to southern China,such as the middlelow reaches of Yangtze River(MLYR),which includes parts of the Yangtze River Delta and the Midwest.However,PM_(2.5)deposition in the NCP is significantly lower than that in the MLYR region,suggesting that in addition to meteorology and emissions,lower deposition is another important factor in the increase in haze levels.Regional transport of pollution in central-eastern China acts as a moderator of pollution levels in different regions,for example by bringing pollution from the NCP to the MLYR region in cold seasons.It was found that in typical haze events the deposition flux of PM_(2.5)during the removal stages is substantially higher than that in accumulation stages,with most of the PM_(2.5)being transported southward and deposited to the MLYR and Sichuan Basin region,corresponding to a latitude range of about 24°N-31°N.