Analysis of Vertical Distribution of Ozone in Winter and Its Transport from Stratosphere to Troposphere in the Pearl River Delta Region of China

The vertical distribution of winter ozone in the Pearl River Delta in 2021 was analyzed using electrochemical concentration cell (ECC) ozonesonde and compared with the ozone Light detection and ranging (LiDAR) data. The transport of stratospheric ozone to the troposphere was also explored. The results show that (1) the maximum value of the stratospheric ozone layer was about 25 km. The stratospheric ozone profile is mainly unimodal, and the stratospheric ozone content was much higher than that of the troposphere. In the troposphere, the ozone content near the ground (0-2 km) was slightly higher than that between 5 and 15km. The ozone profile in the upper and middle troposphere showed a peak structure, which was mainly divided into single peak (22%) and multipeak (77%) profiles. (2) In the middle and lower troposphere, the vertical profile of ozone detected by LiDAR is significantly different from that detected by sounding system. The difference between the two ranged from 10 ppb to 60 ppb at the same height. Ozone sounding can supplement the blind area of the near-ground layer by LiDAR ozone detection and can calibrate the inversion results of LiDAR. (3) On January 5, 2022, stratospheric ozone was transported to the troposphere. The stratospheric intrusion occurred due the high wind speed of the subtropical jet centre over Qingyuan and due to strong subsidence movement. When the stratospheric air mass moved to the troposphere, and subsidence airflow encountered, the ozone concentration near the ground was rapidly increased in a short time. It was identified as an exceptional event.

Automated summary

The analysis of the vertical distribution of winter ozone in the Pearl River Delta in 2021 was conducted using an electrochemical concentration cell (ECC) ozonesonde and compared with ozone Light detection and ranging (LiDAR) data. The study also explored the transport of stratospheric ozone to the troposphere. The results showed significant differences in the ozone profiles detected by LiDAR and the sounding system in the middle and lower troposphere, and the ozone sounding was able to supplement the blind area of near-ground ozone detection by LiDAR.