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|Title: ||Seasonal dependence of peroxy radical concentrations at a Northern hemisphere marine boundary layer site during summer and winter: evidence for radical activity in winter|
|Authors: ||Fleming, Zoe L.|
Monks, Paul S.
Rickard, Andrew R.
Bandy, Brian J.
Penkett, Stuart A.
|Issue Date: ||5-Dec-2006|
|Publisher: ||Copernicus on behalf of the European Geosciences Union|
|Citation: ||Atmospheric Chemistry and Physics, 2006, 6, pp.5415-5433|
|Abstract: ||Peroxy radicals (HO2 +ΣRO2) were measured at
the Weybourne Atmospheric Observatory (52ºN, 1ºE), Norfolk using a PEroxy Radical Chemical Amplifier (PERCA) during the winter and summer of 2002. The peroxy radical
diurnal cycles showed a marked difference between the winter and summer campaigns with maximum concentrations of 12 pptv at midday in the summer and maximum concentrations
as high as 30 pptv (10 min averages) in winter at night. The corresponding nighttime peroxy radical concentrations were not as high in summer (3 pptv). The peroxy radical
concentration shows a distinct anti-correlation with increasing NOx during the daylight hours. At night, peroxy radicals
increase with increasing NOx indicative of the role of NO3 chemistry. The average diurnal cycles for net ozone production, N(O3) show a large variability in ozone production, P(O3), and a large ozone loss,
L(O3) in summer relative to winter. For a daylight average, net ozone production
in summer was higher than winter (1.51±0.5 ppbv h−1 and 1.11±0.47 ppbv h−1, respectively). The variability in NO
concentration has a much larger effect on N(O3) than the peroxy radical concentrations. Photostationary state (PSS) calculations show an NO2 lifetime of 5 min in summer and
21 minutes in the winter, implying that steady-state NO-NO2 ratios are not always attained during the winter months. The
results show an active peroxy radical chemistry at night and that significant oxidant levels are sustained in winter. The net effect of this with respect to production of ozone in winter is unclear owing to the breakdown in the photostationary state.|
|DOI Link: ||10.5194/acp-6-5415-2006|
|Version: ||Publisher Version|
|Status: ||Peer reviewed|
|Rights: ||© Author(s) 2006. This work is licensed
under a Creative Commons License.|
|Description: ||This work is licensed under a Creative Commons License and is also available from http://www.atmos-chem-phys.net/, along with further discussion.|
|Appears in Collections:||Published Articles, Dept. of Chemistry|
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