Observations of hydroxyl and the sum of peroxy radicals at Summit, Greenland during summer 2003

Sjostedt, S.J.; Huey, L.G.; Tanner, D.J.; Peischl, J.; Chen, G.; Dibb, J.E.; Lefer, B.; Hutterli, M.A.; Beyersdorf, A.J.; Blake, N.J.; Blake, D.R.; Sueper, D.; Ryerson, T.; Burkhart, J.; Stohl, A.. 2007 Observations of hydroxyl and the sum of peroxy radicals at Summit, Greenland during summer 2003. Atmospheric Environment, 41 (24). 5122-5137. 10.1016/j.atmosenv.2006.06.065

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Official URL: http://dx.doi.org/10.1016/j.atmosenv.2006.06.065

Abstract/Summary

The first measurements of peroxy (HO2+RO2) and hydroxyl (OH) radicals above the arctic snowpack were collected during the summer 2003 campaign at Summit, Greenland. The median measured number densities for peroxy and hydroxyl radicals were 2.2×108 mol cm−3 and 6.4×106 mol cm−3, respectively. The observed peroxy radical values are in excellent agreement (R2=0.83, M/O=1.06) with highly constrained model predictions. However, calculated hydroxyl number densities are consistently more than a factor of 2 lower than the observed values. These results indicate that our current understanding of radical sources and sinks is in accord with our observations in this environment but that there may be a mechanism that is perturbing the (HO2+RO2)/OH ratio. This observed ratio was also found to depend on meteorological conditions especially during periods of high winds accompanied by blowing snow. Backward transport model simulations indicate that these periods of high winds were characterized by rapid transport (1–2 days) of marine boundary layer air to Summit. These data suggest that the boundary layer photochemistry at Summit may be periodically impacted by halogens.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1016/j.atmosenv.2006.06.065
Programmes:	BAS Programmes > Global Science in the Antarctic Context (2005-2009) > Climate and Chemistry - Forcings and Phasings in the Earth System
ISSN:	1352-2310
Additional Keywords:	Photochemistry, Boundary layer
NORA Subject Terms:	Atmospheric Sciences
Date made live:	10 Dec 2007 12:15 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/1402

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1016/j.atmosenv.2006.06.065

Programmes:

BAS Programmes > Global Science in the Antarctic Context (2005-2009) > Climate and Chemistry - Forcings and Phasings in the Earth System

ISSN:

1352-2310

Additional Keywords:

Photochemistry, Boundary layer

NORA Subject Terms:

Atmospheric Sciences