Evaluating Satellite Detected Tropospheric Ozone Trends above Europe with Ozonesondes

Tropospheric ozone is of significant concern due to its detrimental impact on human health, crops and climate. Assessment of the global tropospheric ozone burden and its trend requires global observations of tropospheric column ozone. Satellite observations are the only source of this important information. There are a total of five satellite products available for the community but they disagree regarding tropospheric column ozone trends. Continual monitoring of ozone profiles from in situ observations such as ozonesondes at different locations around the world provide data necessary for evaluating satellite-detected ozone variability and trends. This study quantified the trends of tropospheric column ozone as measured by ozonesondes over Hohenpeissenberg, Germany. While ozonesondes are flown with a frequency of once a week or less at most stations around the world, Hohenpeissenberg has on average 3-4 launches per week. The tropospheric column ozone was maximum in spring/summer in agreement with other mid-latitude sites. The analysis of tropospheric column ozone trends over Hohenpeissenberg showed no change during the 1996-2018 period. However, the regression analysis of seasonal ozone indicated a statistically significant negative trend during the summer months and a small positive trend during the winter, with no trend during the other seasons. We will use this robust data set to evaluate satellite-detected ozone trends above Europe and will report findings from three publicly available satellite products. This analysis is just the first step in a global-scale intercomparison of newly developed satellite products.