Rising frequency of ozone-favorable synoptic weather patterns contributes to 2015-2022 ozone increase in Guangzhou  

作　　者：Nanxi Liu Guowen He Haolin Wang Cheng He Haofan Wang Chenxi Liu Yiming Wang Haichao Wang Lei Li Xiao Lu Shaojia Fan 

机构地区：[1]School of Atmospheric Sciences,Sun Yat-sen University,and Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519082,China [2]Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary,Key Laboratory of Tropical Atmosphere-Ocean System(Sun Yat-sen University),Ministry of Education,Zhuhai 519082,China

出　　处：《Journal of Environmental Sciences》2025年第2期502-514,共13页环境科学学报(英文版)

基　　金：supported by the Guangdong Basic and Applied Basic Research project (No.2020B0301030004);the Key-Area Research and Development Program of Guangdong Province (No.2020B1111360003);the National Natural Science Foundation of China (No.42105103);the Guangdong Basic and Applied Basic Research Foundation (No.2022A1515011554).

摘　　要：Objective weather classification methods have been extensively applied to identify dominant ozone-favorable synoptic weather patterns(SWPs),however,the consistency of different classification methods is rarely examined.In this study,we apply two widely-used objective methods,the self-organizing map(SOM)and K-means clustering analysis,to derive ozone-favorable SWPs at four Chinese megacities in 2015-2022.We find that the two algorithms are largely consistent in recognizing dominant ozone-favorable SWPs for four Chinese megacities.In the case of classifying six SWPs,the derived circulation fields are highly similar with a spatial correlation of 0.99 between the two methods,and the difference in themean frequency of each SWP is less than 7%.The six dominant ozone-favorable SWPs in Guangzhou are all characterized by anomaly higher radiation and temperature,lower cloud cover,relative humidity,and wind speed,and stronger subsidence compared to climatology mean.We find that during 2015-2022,the occurrence of ozone-favorable SWPs days increases significantly at a rate of 3.2 days/year,faster than the increases in the ozone exceedance days(3.0 days/year).The interannual variability between the occurrence of ozone-favorable SWPs and ozone exceedance days are generally consistent with a temporal correlation coefficient of 0.6.In particular,the significant increase in ozone-favorable SWPs in 2022,especially the Subtropical High type which typically occurs in September,is consistent with a long-lasting ozone pollution episode in Guangzhou during September 2022.Our results thus reveal that enhanced frequency of ozone-favorable SWPs plays an important role in the observed 2015-2022 ozone increase in Guangzhou.

关 键 词：Ozone(O_(3)) Objective weather classification methods Synoptic weather patterns Trends GUANGZHOU 

分 类 号：X51[环境科学与工程—环境工程]