Ozone production and chemical regime analysis in the upper tropical troposphere

Ozone is a greenhouse gas and, after water, the second most relevant contributor to global warming in the upper troposphere. Therefore, understanding and monitoring the processes contributing to ozone production is an important tool in observing the progression of climate change. The two main tropospheric precursors to ozone formation are nitrogen oxides (NO_x = NO + NO₂) and volatile organic compounds (VOC). Depending on their availability, ozone production can be limited by either of its precursors. In our study, we focus on processes contributing to ozone formation and loss in the upper tropical troposphere, where changes in ozone have one of the largest impacts on the radiative forcing. Based on modeled trace gas concentrations and meteorological parameters by the EMAC atmospheric chemistry - general circulation model, we analyze a variety of metrics including net ozone production rates (NOPR), the formaldehyde (HCHO) to NO₂ ratio and the share of methyl peroxyradicals (CH₃O₂) forming HCHO (α_CH3O2) in their ability to indicate the dominating ozone regime in the upper troposphere between 30°N and 30°S latitude.