Peroxy radicals and ozone photochemistry in air masses undergoing long-range transport
Item
Title (Dublin Core)
Peroxy radicals and ozone photochemistry in air masses undergoing long-range transport
Description (Dublin Core)
Concentrations of peroxy radicals (HO<sub>2</sub>+Σ<sub>i</sub><i>R</i><sub>i</sub>O<sub>2</sub>) in addition to other trace gases were measured onboard the UK Meteorological Office/Natural Environment Research Council British Aerospace 146-300 atmospheric research aircraft during the Intercontinental Transport of Ozone and Precursors (ITOP) campaign based at Horta Airport, Faial, Azores (38.58° N, 28.72° W) in July/August 2004. The overall peroxy radical altitude profile displays an increase with altitude that is likely to have been impacted by the effects of long-range transport. The peroxy radical altitude profile for air classified as of marine origin shows no discernable altitude profile. A range of air-masses were intercepted with varying source signatures, including those with aged American and Asian signatures, air-masses of biomass burning origin, and those that originated from the east coast of the United States. Enhanced peroxy radical concentrations have been observed within this range of air-masses indicating that long-range transported air-masses traversing the Atlantic show significant photochemical activity. The net ozone production at clear sky limit is in general negative, and as such the summer mid-Atlantic troposphere is at limit net ozone destructive. However, there is clear evidence of positive ozone production even at clear sky limit within air masses undergoing long-range transport, and during ITOP especially between 5 and 5.5 km, which in the main corresponds to a flight that extensively sampled air with a biomass burning signature. Ozone production was NO<sub>x</sub> limited throughout ITOP, as evidenced by a good correlation (<i>r</i><sup>2</sup>=0.72) between P(O<sub>3</sub>) and NO. Strong positive net ozone production has also been seen in varying source signature air-masses undergoing long-range transport, including but not limited to low-level export events, and export from the east coast of the United States.
Creator (Dublin Core)
Parker, A. E.
Monks, P. S.
Jacob, M. J.
Penkett, S. A.
Lewis, A. C.
Stewart, D. J.
Whalley, L. K.
Methven, J.
Stohl, A.
Date (Dublin Core)
2018-08-10
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acpd-9-18793-2009
https://acp.copernicus.org/preprints/acp-2009-497/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
