Night-time measurements of HOx during the RONOCO project and analysis of the sources of HO2
Atmospheric Chemistry and Physics
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Walker, H., Stone, D., Ingham, T., Vaughan, S., Cain, M., Jones, R., Kennedy, O., et al. (2015). Night-time measurements of HOx during the RONOCO project and analysis of the sources of HO2. Atmospheric Chemistry and Physics, 15 8179-8200. https://doi.org/10.5194/acp-15-8179-2015
Measurements of the radical species OH and HO2 were made using the fluorescence assay by gas expansion (FAGE) technique during a series of night-time and daytime flights over the UK in summer 2010 and winter 2011. OH was not detected above the instrument's 1σ limit of detection during any of the night-time flights or during the winter daytime flights, placing upper limits on [OH] of 1.8 × 10^6 molecule cm^−3 and 6.4 × 10^5 molecule cm^−3 for the summer and winter flights, respectively. HO2 reached a maximum concentration of 3.2 × 10^8 molecule cm^−3 (13.6 pptv) during a night-time flight on 20 July 2010, when the highest concentrations of NO3 and O3 were also recorded. An analysis of the rates of reaction of OH, O3, and the NO3 radical with measured alkenes indicates that the summer night-time troposphere can be as important for the processing of volatile organic compounds (VOCs) as the winter daytime troposphere. An analysis of the instantaneous rate of production of HO2 from the reactions of O3 and NO3 with alkenes has shown that, on average, reactions of NO3 dominated the night-time production of HO2 during summer and reactions of O3 dominated the night-time HO2 production during winter.
This work was funded by the UK Natural Environment Research Council (NE/F004664/1). The authors would like to thank ground staff, engineers, scientists, and pilots involved in RONOCO for making this project a success. Airborne data were obtained using the BAe 146-301 Atmospheric Research Aircraft (ARA) flown by Directflight Ltd. and managed by the Facility for Airborne Atmospheric Measurements (FAAM), which is a joint entity of the Natural Environment Research Council (NERC) and the Met Office.
External DOI: https://doi.org/10.5194/acp-15-8179-2015
This record's URL: https://www.repository.cam.ac.uk/handle/1810/254777
Attribution 2.0 UK: England & Wales
Licence URL: http://creativecommons.org/licenses/by/2.0/uk/
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