ASSESSMENTS OF FORECAST PRODUCTS OF AIR QUALITY FORECASTING SYSTEM BASED ON GRAPES-CMAQ IN ZHONGSHAN CITY

MAI Jian-hua; YU Ling-ling; DENG Tao; JIANG Zheng-ming; TANG Pei; LIU Jiang-shun

doi:10.16032/j.issn.1004-4965.2018.01.008

Abstract：In this study,forecast products for 2016,including AQI level,primary pollutant,and PM2.5 and O3 concentrations,from an air quality forecasting system based on GRAPES-CMAQ model in Zhongshan city are assessed with the observations.The annual average TS score of forecasted AQI level was up to 0.66 and the best scores were found in June and July.When the observed AQI level was the first-class,the TS score was up to 0.84,but the TS score dropped evidently when the air pollution got worse,indicating that the model still could not give good performance in severe air pollution events.The annual average TS scores for the forecast of primary pollutants of O3,PM and NO2 were 0.21,0.24 and 0.24,respectively.The PO for O3 and NO2 were up to 0.78 and 0.76,respectively,while the FAR for PM was 0.71.The annual average forecasted PM2.5 concentration was a little overestimated compared to the observations and the correlation coefficient was 0.59 for the whole year.However,the performances of the model were not stable among the months with heavy haze pollution.The correlation coefficient for O3 was 0.7 in 2016,and the coefficient of July to November with severe O3 pollution were all over 0.5.The forecasted O3 concentrations were all underestimated in these five months.An O3 pollution case during 2nd to 7th October 2016 was studied based on the forecasted data of GRAPES.It was found that the rainfall area and intensity in Pearl River Delta as well as the wind speed were all overestimated by GRPAES in the day time,leading to the underestimation of forecasted O3 concentrations in this event.