Characteristics of the vertical distribution of tropospheric ozone in late autumn at Yangjiang station in Pearl River Delta (PRD), China. Part?: Observed event

Ozone has become the main factor affecting air quality in Pearl River Delta (PRD) recent years, and a clear understanding source of ozone pollution is top priority prevention. However, vertical distribution tropospheric PRD poorly understood. Based on daily sounding data obtained Yangjiang (111°58'00" E, 21°50'00" N), Guangdong Province, from 18 November tjo 3 December 2013, detailed its influencing factors were determined compared with weekly autumn profile at Hong Kong Observatory (HKO) corresponding column (TCO) datasets Monitoring Instrument (OMI) Microwave Limb Sounder (MLS) onboard satellite AURA. Overall, profiles observed are accordance those HKO terms structure. The TCO values 34.2 ± 4.0 34.3 4.6 DU, respectively, that are, 4 DU higher than data, indicating OMI/MLS product underestimates level region. indicate significant variations structure concentration during observation period. A peak permanently occurs lower troposphere 1.1 0.4 km above surface. structural difference mainly reflected presence low-ozone strata (below 30 ppbv) near tropopause peaks high-ozone stratification middle upper troposphere. average concentrations lower, middle, 65.2 9.9, 57.8 7.7, 71.8 13.6 ppbv, which ground-level (48.9 9.4 ppbv). analysis characteristics, weather conditions, backward trajectories, it can be concluded caused by regional transport tropical mass cyclone storm area. Potential vorticity shows stratosphere-troposphere exchange (STE) reason for formation varying Photochemical reactions represent STE also an important troposphere, leading to increase surface ~10.9 ppbv.