Assessment of Ozone Formation and its Precursors in a Continental and Maritime Transition Area During the OWLETS 2017 Field Campaign

Tropospheric ozone (O₃) impacts human health and vegetation and plays a central role in the oxidation of chemically and climatically relevant trace gases. Due to the importance of O₃ and its precursors to air quality and climate change, it has received continuous attention in the past decades from both the scientific and regulatory communities. With the aim to characterize pollutant formation, transport, and enhancement in land/water transition regions, the OWLETS (Ozone Water-Land Environmental Transition Study) campaign was carried out during summer 2017, investigating the southern Chesapeake Bay region. In this study, we utilize measurements from the NASA C-23 Sherpa aircraft that overflew and spiraled above intensive observation sites within the study region, determining the mixing ratios of the various trace gases. These measurements included more than 35 species of non-methane volatile organic compounds (NMVOCs), which provide additional information regarding the source of emissions (e.g. biogenic vs. anthropogenic) as well as insight into photochemical processing. These observations will be compared to Pandora trace gas spectrometers that were deployed at several key sites overflown by the Sherpa during the OWLETS campaign. The Pandora spectrometer provide total columns of O₃ and nitrogen dioxide (NO₂) information. The measurements obtained from the Sherpa aircraft and Pandora trace gas spectrometers can help to understand the relative contribution of NO₂ and NMVOCs to O₃ formation. Due to the Chesapeake Bay's geography, it is affected by unique meteorological conditions and relatively fast photochemical processes associated with NMVOCs.