OH and HO2 chemistry in the North Atlantic free troposphere

• Published in: Geophysical research letters Vol. 26; no. 20; pp. 3077 - 3080
• Main Authors: Brune, W. H., Tan, D., Faloona, I. F., Jaeglé, L., Jacob, D. J., Heikes, B. G., Snow, J., Kondo, Y., Shetter, R., Sachse, G. W., Anderson, B., Gregory, G. L., Vay, S., Singh, H. B., Davis, D. D., Crawford, J. H., Blake, D. R.
• Format: Journal Article
• Language: English
• Published: Washington, DC Blackwell Publishing Ltd 15-10-1999; American Geophysical Union
• Subjects: Chemical composition and interactions. Ionic interactions and processes; Earth, ocean, space; Exact sciences and technology; External geophysics; Meteorology; Atlantic Ocean; North Atlantic; Nitrogen oxide; Airplane; Marine atmosphere; Cirrus; Hydroperoxy radicals; Troposphere; Aerosols; Hydroxyl radicals; Air pollution; Exhaust gas; Heterogeneous reaction
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/1999GL900549

Interactions between atmospheric hydrogen oxides and aircraft nitrogen oxides determine the impact of aircraft exhaust on atmospheric chemistry. To study these interactions, the Subsonic Assessment: Ozone and Nitrogen Oxide Experiment (SONEX) assembled the most complete measurement complement to date for studying HOx (OH and HO2) chemistry in the free troposphere. Observed and modeled HOx agree on average to within experimental uncertainties (±40%). However, significant discrepancies occur as a function of NO and at solar zenith angles >70°. Some discrepancies appear to be removed by model adjustments to HOx‐NOx chemistry, particularly by reducing HO2NO2 (PNA) and by including heterogeneous reactions on aerosols and cirrus clouds.