Influence of typhoon track in northwest Pacific on ozone pollution in autumn in Shantou City
In this study,the characteristics of typhoons in the Northwest Pacific Ocean and their effects on autumn ozone pollution in Shantou were analyzed using tropical cyclone data from 2015 to 2022,along with pollutant and meteorological data from the National control station in Shantou,and Global Data Assimilation System(GDAS)data obtained from the National Center for Environmental Prediction(NCEP).The results show that:A total of 234 typhoons occurred in the Northwest Pacific Ocean during this period.with the highest occurrence in summer(106),followed by autumn,and fewer in spring and winter.Through the application of the K-means clustering method,the typhoons were categorized into four types:W(westward landfall in Myanmar and Laos),L(northwest landfall in China),C(dissipation near the South China Sea and East China Sea),and ET(northwest and northeast turn after formation).Ozone concentration were found to be highest during C-type and ET-type typhoons,accompanied by rising temperatures,decreasing relative humidity,and increased solar radiation.Additionally,conditions of calm or light winds were conducive to ozone generation and accumulation.Conversely,ozone concentrations during L-type typhoons were significantly lower,marking these as clean air days.In such cases,meteorological conditions were characterized by rising temperatures,increased relative humidity,low solar radiation,and strong winds,facilitating ozone dispersion and dilution.The peak in ozone concentration during typhoon-affected days occurred between 15:00 and 17:00,with regional ozone transport playing a significant role.Air mass analysis over 72 hours indicated that the primary sources of ozone were located in Shanwei,Huizhou,Zhejiang,and Fujian provinces,with the air mass predominantly arriving from the northeast.Analysis of typical typhoon cases revealed that,compared to non-typhoon periods,photochemical ozone formation was more favourable during typhoon-affected periods due to higher temperatures,lower relative humidity,and stronger solar radiation.The regional transport effect of pollution during Typhoon"Meimei"is significant,and the ozone concentration will show a phenomenon of"peak lag".China has produced a pollution transmission channel from Anhui to Jiangxi and east Guangdong.The results of process analysis showed that the main ozone source contribution during typhoon period was chemical process(41.2％),followed by horizontal transmission(30.3％)and vertical transmission(28.4％).
Typhoonozone pollutionShantou Citymeteorological element
万方数据
维普
