[Sensitivity Analysis of Ozone Generation in Guangdong Province Based on OMI Satellite and Ground Observation Data]

Based on Ozone （O₃） Monitoring Instrument satellite remoting sensing data and reanalysis meteorological data, an analysis was conducted on the spatiotemporal distribution and trends of tropospheric nitrogen dioxide （NO₂） and formaldehyde （HCHO） in Guangdong Province from 2015 to 2020. The study also examined the changing characteristics of O₃ generation sensitivity in relation to meteorological parameters. The results indicated that during 2015-2020, the tropospheric NO₂ column concentration in Guangdong Province exhibited a distribution pattern with the Pearl River Delta （PRD） Region as the high-value center gradually decreasing towards the surrounding areas, with the most substantial decline observed in the Pearl River Delta. The HCHO column concentration showed a pattern of higher values in the PRD and lower values in the other regions. While most areas exhibited a decreasing trend in HCHO column concentration, the spatial distribution was more dispersed compared to that of NO₂. In most regions, the ratio of HCHO to NO₂ （FNR） showed an increasing trend. The area under VOCs-NO synergistic control decreased, whereas the area under NO control increased. By 2020, the proportions of VOCs control area, VOCs-NO synergistic control area, and NO control area in Guangdong Province were 0.5%, 13.1%, and 86.4%, respectively. The FNR value showed an increasing trend； a positive correlation with 2 m temperature, relative humidity, downward surface shortwave radiation, and boundary layer height； and a negative correlation with 10 m wind speed and sea level pressure. The three most influential meteorological factors were downward surface shortwave radiation（DSSR）, relative humidity, and 2 m temperature, impacting the FNR value the most.