Assessment of OMI/MLS Satellite-Derived Tropospheric Ozone Product for Predicting Surface-Level Ozone Concentrations

Ground-level ozone is a hazardous air pollutant that contributes to respiratory and cardiovascular morbidity and mortality, as well as to climate change and vegetation damage. Despite its significance, global surface ozone monitoring remains spatially sparse, particularly outside of North America, Europe, and East Asia. Satellite-based products such as the Ozone Monitoring Instrument/Microwave Limb Sounder (OMI/MLS) tropospheric column ozone (TCO) dataset offer a potential solution for improving estimates of global ozone at ground level. This study evaluates the performance of the OMI/MLS TCO product as a predictor of surface-level ozone by comparing it to monthly average ground-based Maximum Daily 8-hour Average (MDA8) ozone measurements from the TOAR-II database (2004–2020). Linear regressions were conducted globally, as well as by year, world region, value range, and month. Although global correlations were modest (R² = 0.30 globally), a positive trend was found between the TCO product and ground-based measurements. The satellite product captured expected seasonal and hemispheric trends in surface ozone, and the regression results were used to generate monthly global maps of estimated ground-level ozone. While not a substitute for in situ measurements, OMI/MLS TCO shows potential as an independent observational input to global data fusion methods in areas lacking ground-based monitoring.