In the research project OzonEval, funded by the German Federal Environment Agency, the uncertainty of dispersion calculations of ozone concentration with chemical transport models is estimated. The model quality of current climatic conditions is investigated and a new method for the dynamic evaluation of the models is developed. This will be used for the subsequent dynamic evaluation of ozone episodes as well as ozone distributions under normal conditions over the federal territory of Germany. The focus of the project analysis is on the evaluation of short-term time scales (<1 year).

For the study, a model ensemble simulation over Germany for the year 2019, with harmonized input data (meteorology and emissions), is calculated. Dynamic evaluation of the model calculations as well as artificial sensitivity runs are used to comprehensively compare the models. Differences in processes that are most important for ozone formation and depletion can thus be highlighted. The suitability of the individual models and the model ensemble for the investigation of impacts as well as their climatic changes of future ozone distribution including ozone episodes can thus be tested or assessed.

The models will also be operationally evaluated according to the FAIRMODE metrics to obtain an overall picture of the respective model performance for Germany.

New knowledge on the description of ozone formation and depletion processes in models and on the consideration of ozone variability with respect to meteorology will be used to improve the FAIRMODE quality assurance methodology for ozone.

The Tropospheric Environmental Working Group of the Institute for Meteorology is also part of the OzonEval (UBA) consortium and contributes significantly to the overall project with project coordination and dynamic evaluation.