Spatiotemporal variations of ozone(O3)taken from the Copernicus Atmosphere Monitoring Ser-vice(CAMS)and the second Modernn-Era Retrospective Analysis for Research and Applications(MERRA-2)were intercompared and evaluated with ground and ozone-sonde observations over China in 2018 and 2019.Intercomparison of the surface ozone from CAMS and MERRA-2 reanaly-sis showed significant negative bias(CAMS minus MERRA-2,same below)at Tibetan Plateau of up to 80 μg/m3,and the average R2 was about 0.6 across China.Evaluated with the ground observa-tions from China National Environmental Monitoring Center(CNEMC),we found that CAMS and MERRA-2 reanalysis were capable of capturing the key patterns of monthly and diurnal variations of surface ozone over China except for the western region,and MERRA-2 overestimated the obser-vations compared to CAMS.Vertically,the CAMS profiles overestimated the ozone-sonde from the World Ozone and Ultraviolet Radiation Data Center(WOUDC)above 200 hPa with the magnitude reaching up to 150 μg/m3,while little bias was found between the reanalysis and observations be-low 200 hPa.Intercomparison drawn from the vertical distribution between CAMS and MERRA-2 reanalysis showed that the negative bias appeared throughout the troposphere over China,while the positive bias emerged in the upper troposphere and lower stratosphere(UTLS)with high order of magnitude exceeding 100 μg/m3,indicating large uncertainties at higher altitudes.In summary,we concluded that CAMS reanalysis showed better agreement with the observations in contrast to MERRA-2,and the large discrepancy especially at higher altitudes between these two reanalysis datasets could not be ignored.

Yujing Zhang;Jie Li;Jianjun Li;Xiaole Pan;Wei Wang;Lili Zhu;Zixi Wang;Xueshun Chen;Wenyi Yang;Zifa Wang

The State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Center for Excellence in Regional Atmospheric Environment,Institute of Urban Environment,Chinese Academy of Sciences,Xiamen 361021,China;China National Environmental Monitoring Center,Beijing 100012,China

环境科学学报（英文版）

[1]Yujing Zhang;Jie Li;Jianjun Li;Xiaole Pan;Wei Wang;Lili Zhu;Zixi Wang;Xueshun Chen;Wenyi Yang;Zifa Wang-.An intercomparison of ozone taken from the Copernicus atmosphere monitoring service and the second Modern-Era retrospective analysis for research and applications over China during 2018 and 2019)[J].环境科学学报（英文版）,2022(04):514-525

Modernn,intercompared,sonde,reanaly,CNEMC,WOUDC

intercomparison,ozone,taken,from,Copernicus,atmosphere,monitoring,service,second,Era,retrospective,research,applications,China,during,Spatiotemporal,variations,O3,Atmosphere,Monitoring,Ser,CAMS,Retrospective,Analysis,Research,Applications,MERRA,were,evaluated,ground,observations,Intercomparison,surface,showed,significant,negative,bias,minus,same,below,Tibetan,Plateau,average,was,about,across,Evaluated,National,Environmental,Center,found,that,reanalysis,capable,capturing,key,patterns,monthly,diurnal,except,western,region,overestimated,Vertically,profiles,World,Ozone,Ultraviolet,Radiation,Data,above,hPa,magnitude,reaching,while,little,between,drawn,vertical,distribution,appeared,throughout,troposphere,positive,emerged,upper,lower,stratosphere,UTLS,order,exceeding,indicating,large,uncertainties,higher,altitudes,summary,concluded,better,agreement,contrast,discrepancy,especially,these,two,datasets,could,not,ignored

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