基于GRAPES模式的广州地区大气输送扩散参数及其对PM_(2.5)预报的应用

STUDY ON TRANSPORT AND DIFFUSION PARAMETERS BASED ON GRAPES MODEL AND THEIR FORECAST APPLICATION TO PM_(2.5) IN GUANGZHOU AREA

利用2010年11月—2011年11月广州地区PM2.5逐时监测资料以及GRAPES模式计算的四种大气输送扩散参数预报值,分析评估模式描述四种大气输送扩散参数的性能及其预报广州地区PM2.5浓度的可行性,结果表明：GRAPES模式不同时刻起报的地面通风系数、平均通风系数和湍流动能的预报稳定性与一致性较好,而垂直交换系数相对较差。垂直交换系数、地面通风系数、平均通风系数和湍流动能的量级分别为101、103、103和10-1~100。PM2.5浓度与大气输送扩散参数呈显著负相关,其中PM2.5与14时起报的垂直交换系数相关性最好。使用临界成功指数CSI对PM2.5浓度进行预报检验,得到垂直交换系数对PM2.5的预报稳定性较好,垂直交换系数能大概判别PM2.5为＂污染＂与＂清洁＂情况,临界成功指数部分可达70%。垂直交换系数与PM2.5浓度存在显著的超前滞后相关,预报PM2.5浓度是否为＂污染＂与＂清洁＂可同时参考原序列及滞后序列的预报效果。

Based on the monitoring data of PM2.5 and the forecast data of four atmospheric transport and diffusion parameters calculated by GRAPEs model from November 2010 to November 2011 in the Guangzhou area, the property of the model in describing four atmospheric transport and diffusion parameters and the feasibility of forecasting the concentration of PM2.5 in the Guangzhou Area were analyzed and assessed. The results showed that GRAPEs model＇s stability and consistency were better in forecasting Surface Ventilation Index（SVI）, Mean Ventilation Index（MVI） and Turbulent Kinetic Energy（TKE） than Vertical Exchange Index（VEI）. The magnitude of VEI, SVI, MVI and TKE was 101, 103, 103 and 10-1~100 respectively. The concentration of PM2.5 and atmospheric transport and diffusion parameters were in obvious anti-correlation. Specifically, the correlation of PM2.5 with VEI, which started to forecast at 14：00, was relatively better. Critical Success Index（CSI） was used to carry out the forecast verification of PM2.5. It was found that VEI had good stability to forecast PM2.5. The VEI can roughly distinguish a ‘pollution＇ level of PM2.5 from a ‘clean＇ level of PM2.5, with the CSI partly reaching 70%. The concentration of PM2.5 and VEI were in obvious lead and lag correlations. The forecast of ‘pollution＇ and ‘clean＇ level of PM2.5 can take into account the forecast effect of the original sequence and the lag sequence.