In recent years, ozone pollution has become a prominent problem affecting the air quality in spring and summer in southern Hebei. It is of great significance to explore the characteristics of ozone heavy pollution events and meteorological factors for the fine management and prevention of atmospheric environment in this area. In this article, three severe ozone pollution events occurring in southern Hebei in late spring and early summer of 2017, 2019 and 2022 (referred to as “Case 1”, “Case 2” and “Case 3”, respectively) were selected, and the characteristics of heavy pollution events and meteorological factors were compared and analyzed by using environmental monitoring data and reanalysis data. The results show that the ozone mass concentration of the three heavy pollution events showed an S-shaped distribution in the vertical direction, and the diurnal variation of ozone mass concentration at the characteristic layer gradually weakened with increasing height. The three pollution events all had stratospheric ozone intrusion. The intrusion heights of Case 1 and Case 3 were higher, and the contribution to heavy pollution days was smaller. The stratospheric ozone intrusion height of Case 2 was lower. The diurnal variation of temperature and ozone mass concentration is positively correlated, and the temperature of each height layer in Case 3 is the highest. The relative humidity is negatively correlated with the diurnal variation of ozone mass concentration, and the smaller the humidity is, the higher the ozone mass concentration is. The stronger the upward movement in the middle and lower layers, the higher the extension height of high mass concentration ozone. The convergence ascending motion near the ground is dominant at night, which is conducive to the lifting of high-concentration ozone from the ground to the lower troposphere, and it is mainly divergent sinking during the day, and the higher ozone mass concentration in the residual layer increases the ground ozone mass concentration through vertical diffusion.

A local heavy rain occurred in the southernmountainous region of Yongchang County on July 14, 2006 was analyzed synthetically from several aspects of physical quantities, moisture condition, p recip itation intensity, satellite images and radar features. Results show that the wind shear convergence at the level of 500 hPa ismain factor resulting in thisweather event, and the wind vertical shear p rovides favorable conditions to ascent development of airflow; the convective cells caused by the external flow of vortex cloud system bring on this strong convective p recip itation. Meanwhile, we found that analysis on energy and Showalter index fields could be a good indication to strong convective weather forecast.