污染源反演对重点城市群夏季O_(3)模拟的改进效果评估

Improvement of the Summer Ozone Simulation over Key Cite-Clusters in China through Emission Inversion Method

在嵌套网格空气质量预报模式系统(NAQPMS)的基础上,采用污染源反演方法优化以中国多尺度排放清单(MEIC)为主的先验排放清单中臭氧(O_(3))前体物排放量估计.分析时段为2019年6-8月,重点评估了污染源反演对我国"2+26"城市、长三角、珠三角、成渝4个重点城市群O_(3)模拟的改进效果.评估结果表明,污染源反演获得的"2+26"城市、长三角、珠三角的氮氧化物(NO_(x))排放速率整体低于先验清单的排放速率约0.6μg m^(-2) s^(-1),但反演的挥发性有机物(VOCs)排放速率在"2+26"城市整体上高于先验清单的排放速率约0.5μg m^(-2) s^(-1).利用反演的NOx和VOCs排放量和NAQPMS模式对4个城市群O_(3)进行模拟,发现反演排放数据可以显著改进夏季O_(3)模拟性能,使得O_(3)日最大8小时平均值(MDA8-O_(3))模拟的均方根误差(RMSE)从40-60μg/m^(3)降低至20-30μg/m^(3),模拟值与观测值的相关系数从0.6-0.7提升至0.8以上,模拟和观测O_(3)浓度日变化峰值差异从2-50μg/m^(3)缩小到2-20μg/m^(3).本文结果表明基于地面观测数据的污染源反演可以有效改进重点城市群的O_(3)模拟性能,反演的O_(3)前体物排放量与先验清单的排放量差异可为先验清单效验和评估提供参考.

Based on the Nested Grid Air Quality Prediction Model System(NAQPMS),the emission source inversion method is utilized to optimize the estimation of ozone(O_(3))precursor in the emission a priori inventory dominated by China Multi-Scale Emission Inventory(MEIC).From June to August 2019,the effect of improving O_(3) simulation by employing source inversion emission inventory is mostly examined in“2+26”Cities,Yangtze River Delta,Pearl River Delta,and Chengdu−Chongqing urban agglomerations with severe O_(3) pollution from June to August 2019(summer).The evaluation results show that the nitrogen oxide(NO_(x))emission rate obtained by source inversion is lower than the a priori inventory emission rate of about 0.6μg m^(-2) s^(-1),but the volatile organic compounds(VOCs)emission rate of inversion is higher than the a priori inventory emission rate of about 0.5μg m^(-2) s^(-1) in“2+26”cities.The source inversion emission inventory is used to simulate O_(3) in four urban agglomerations,and the simulated performance of O_(3) in summer could be significantly improved by inversion emission data,which reduces the root-mean-square error(RMSE)of the maximum eight-hour mean of O_(3)(MDA8-O_(3))from 40–60μg/m^(3)to 20–30μg/m^(3)and increases the correlation coefficient from 0.6–0.7 to more than 0.8.The discrepancy between the simulated and observed diurnal variation peaks of O_(3) narrowed from 2–50μg/m^(3)to 2–20μg/m^(3).The results of this study show that pollution source inversion based on ground observation data may effectively improve the performance of O_(3) simulation in the key urban agglomeration,and the difference between the emissions of O_(3) precursor inversion emissions and the a priori inventory may provide a reference for the effectiveness and evaluation of the a priori inventory.