Abstract:Based on the ERA5 high-resolution monthly average reanalysis data provided by the European Centre for Medium-Range Weather Forecasts (ECMWF), the influence of the South Asia High (SAH) on the ozone distribution in the upper troposphere and lower stratosphere during June to August in summer for 30 years from 1991 to 2020 was analyzed. Results show that the ERA5 data can clearly depict the monthly variation and oscillation characteristics of SAH from June to August, and also can well reflect the corresponding low ozone values as a recognized phenomenon. Furthermore, ERA5 data can also reveal a strong link between the range and intensity variation of ozone lows and SAH. When the SAH is anomalously strong (weak), the ozone lows in the neighboring areas strengthen (weaken), and when the center of the SAH oscillates, the low center of the ozone zonal deviation also changes, and this change is more pronounced when the SAH is strong. However, this connection is complex and its correlation varies from month to month. The effect of SAH on ozone concentration is mainly related to the air transport in the troposphere, and the location and extent of the low center of ozone corresponds to the low region of the potential vorticity and the negative values of the potential temperature zonal deviation.