The use of meteorological parameters to compare tropospheric ozone measurements over Boulder, CO

Tropospheric ozone is important for air quality and climate change issues, as it affects the health of humans and the environment and acts as a greenhouse gas. Therefore, continuous monitoring of tropospheric ozone is necessary for assessment of climate changes on the global, regional and local environment. In Boulder, CO, tropospheric ozone is measured by both the Dobson ozone spectrophotometer and by ozonesondes. An Umkehr ozone measurement is taken by the Dobson every clear, sunny day, whereas an ozonesonde is launched approximately one time a week. Although ozonesondes can provide high resolution information on vertical ozone distribution, they are more expensive than the lower-resolution Dobson ground-based measurement. The correlation between the Umkehr and ozonesonde tropospheric ozone values for measurements taken on the same day was found to be about 0.5, and the correlation for measurements taken on different days was lower. As ozone in the troposphere is influenced by atmospheric dynamics, meteorological parameters and trajectories were used to determine if ozone measurements taken on different days were comparable. We will show that using these parameters and trajectories to filter out days for comparison, results in an improved correlation between different-day Umkehr and ozonesonde tropospheric ozone values.