中国长三角地区PM_(2.5)时空分布数值模拟研究

Numerical simulation on the spatiotemporal distribution of PM_(2.5) in the Yangtze River Delta

利用第三代空气质量预报模式LOTOS-EUROS(Long Term Ozone Simulation-European Operational Smog)对2018年中国长三角地区细颗粒物(PM_(2.5))浓度的时空分布进行数值模拟,通过对比模拟结果与地面观测值,验证模式对PM_(2.5)长期特征模拟的合理性并探讨长三角地区PM_(2.5)的时空分布特征。结果表明:LOTOS-EUROS模式可以较好地再现中国长三角地区PM_(2.5)浓度的时空分布特征,监测站点观测值和模拟值的整体相关系数达到0.64,可以用于长三角地区细颗粒物的模拟。长三角地区PM_(2.5)浓度呈冬高夏低,西北高东南低的特征。冬季PM_(2.5)浓度高值出现在长三角地区的西北部,安徽省等地区的浓度水平最大值可达到160μg·m^(-3);春季和秋季PM_(2.5)浓度的高值集中在30°N以北、120°E以西地区,浓度为40—80μg·m^(-3);而夏季PM_(2.5)浓度水平大幅度降低,大部分地区维持在20—40μg·m^(-3),低值中心出现在长三角地区东南部沿海城市,低于10μg·m^(-3),最低值可达5μg·m^(-3)。

The spatiotemporal characteristics of fine particulate matter(PM_(2.5))concentration over the Yangtze River Delta in 2018 were simulated using the third-generation air quality forecast model,Long Term Ozone Simulation-European Operational Smog(LOTOS-EUROS).Comparing with ground observations,the rationality of this model to simulate the long-term characteristics of PM_(2.5) concentration was verified,and the spatiotemporal variation of PM_(2.5) in this region was explored.The results showed that the LOTOS-EUROS model can well reproduce the spatiotemporal characteristics of PM_(2.5) concentration in the Yangtze River Delta.The overall correlation coefficient between the observation and simulation values of the monitoring stations reaches 0.64,which means that this model can be applied to the simulation of fine particulate matter in the Yangtze River Delta.The PM_(2.5) concentration in the Yangtze River Delta is high in winter of the northwest,and is low in summer of the southeast.High PM_(2.5) concentrations in winter occur in the northwestern region of the Yangtze River Delta,and the maximum concentrationin in Anhui province and other areas can reach 160μg·m^(-3).In spring and autumn,high PM_(2.5) concentrations are concentrated in the north of 30°N and the west of 120°E,with values ranging from 40μg·m^(-3) to 80μg·m^(-3).Whereas in summer,PM_(2.5) concentration decreases significantly and remains around 20-40μg·m^(-3) in most areas.The low-value center of PM_(2.5) concentration(lower than 10μg·m^(-3))occurs in coastal cities in the southeast of the Yangtze River Delta,with the lowest value reaching 5μg·m^(-3).