| In recent years,the phenomenon of ozone（O3）pollution in summer and autumn time has become more and more prominent in eastern cities of China.As the typical cities,Jiaxing City of Zhejiang Province and Shenzhen City of Guangdong Province,the O3 pollution of them has become the focus of the government and the public.The boundary layer is between the surface and the free atmosphere,and it is the layer where pollutants are concentrated.Therefore,the study of O3 pollution inside the boundary layer can province important reference significance for the formulation of local pollution prevention and control programs.In this study,O3 differential absorption lidar observational data,as well as the surface observational meteorological factors and conventional air quality data were used in the summer of 2018（August）in Jiaxing city,the autumn of 2019（September 12-October 27）in Shenzhen city,to quantitative analysis the pollution meteorology of O3 and further study the vertical characteristics of O3 pollution.The mainly research results are as follows:（1）The domination meteorological factors that influence O3 production:The weather background with high temperature,high actinic radiation and low relative humidity were conductive to the generation of O3.During daytime,O3 is positively correlated with T,actinic radiation and negatively with RH.With the increasing of T,actinic radiation and RH,the O3 presents a stepwise upward and downward trend respectively,they are the dominating factors for the generation of high concentration O3 pollution.According to the one-year data statistics of Jiaxing area show that O3pollution occurred with the range of T=24～36℃ and RH=36%～77%,respectively.The T above 24℃ and the relative humidity below 77%can be used as the meteorological threshold for early warning of O3 pollution.The analysis of the relationship between JNO2 and O3 in Shenzhen shows that the JNO2 above 0.007s-1 was most conducive to the generation of O3.（2）The vertical distribution characteristics of O3 inside boundary layer:The O3lidar observational results show that the vertical O3 profiles were similar between episodic and clean days,which exhibited an O3 peak between 600～800m in Jiaxing area and between 300～500m in Shenzhen area,while the O3 concentrations decreased beyond this range.During nighttime,O3 was relative low concentration inside the residual layer in Jiaxing area,while high O3 concentration was observed inside the residual layer as well as near the top of boundary layer in Shenzhen area.（3）The diurnal evolution characteristics of O3 inside boundary layer:As for Jiaxing area,the O3 below 800m was relatively constant at night and in the early morning.It increased rapidly from 7:00～11:00,until reaching a peak at the time of12:00～16:00 and decreased gradually after 17:00.As for Shenzhen area,the O3 below600m was decreased hour by hour in the early morning,while maintaining high concentration at night.It increased rapidly from 7:00～11:00,until reaching a peak at the time of 12:00～16:00 and decreased gradually after 18:00.（4）The boundary layer process that influence surface-level O3.The middle and upper boundary layer,as well as the residual layer are the high O3concentration area.O3 inside this area would down to the surface due to the upward development of mixing layer and breakthrough the residual layer in the morning,and the boundary layer is fully developed in the afternoon,respectively,which led to a rapid increase in the ground-level O3 and further aggravate ground-level O3 pollution.The quantitative analysis of Shenzhen area shown that high O3 concentration inside the residual layer contributed54%±6%of the surface-level O3 at 9:00,and the average contribution of O3 near the top of boundary layer to the surface-level O3 at 14:00 was 26%±9%during the heavy O3 pollution episodes which under the weather background of Subtropical High and the impact of typhoon periphery.Revealing the importance of the contribution of in the residual layer and near the top of boundary layer. |
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