Large mixing ratios of atmospheric nitrous acid (HONO) at Concordia (East Antarctic plateau) in summer: a strong source from surface snow?

Legrand, M.; Preunkert, S.; Frey, M. ORCID: https://orcid.org/0000-0003-0535-0416; Bartels-Rausch, T.; Kukui, A.; King, M. D.; Savarino, J.; Kerbrat, M.; Jourdain, B.. 2014 Large mixing ratios of atmospheric nitrous acid (HONO) at Concordia (East Antarctic plateau) in summer: a strong source from surface snow? Atmospheric Chemistry and Physics, 14 (18). 9963-9976. 10.5194/acp-14-9963-2014

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Abstract/Summary

During the austral summer 2011/2012 atmospheric nitrous acid was investigated for the second time at the Concordia site (75°06' S, 123°33' E) located on the East Antarctic plateau by deploying a long path absorption photometer (LOPAP). Hourly mixing ratios of HONO measured in December 2011/January 2012 (35 ± 5.0 pptv) were similar to those measured in December 2010/January 2011 (30.4 ± 3.5 pptv). The large value of the HONO mixing ratio at the remote Concordia site suggests a local source of HONO in addition to weak production from oxidation of NO by the OH radical. Laboratory experiments demonstrate that surface snow removed from Concordia can produce gas phase HONO at mixing ratios half that of NOx mixing ratio produced in the same experiment at typical temperatures encountered at Concordia in summer. Using these lab data and the emission flux of NOx from snow estimated from the vertical gradient of atmospheric concentrations measured during the campaign, a mean diurnal HONO snow emission ranging between 0.5 and 0.8 × 109 molecules cm−2 s−1 is calculated. Model calculations indicate that, in addition to around 1.2 pptv of HONO produced by the NO oxidation, these HONO snow emissions can only explain 6.5 to 10.5 pptv of HONO in the atmosphere at Concordia. To explain the difference between observed and simulated HONO mixing ratios, tests were done both in the field and at lab to explore the possibility that the presence of HNO4 had biased the measurements of HONO.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.5194/acp-14-9963-2014
Programmes:	BAS Programmes > Polar Science for Planet Earth (2009 - ) > Chemistry and Past Climate
ISSN:	1680-7316
Date made live:	21 May 2014 12:43 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/507280

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.5194/acp-14-9963-2014

Programmes:

BAS Programmes > Polar Science for Planet Earth (2009 - ) > Chemistry and Past Climate

ISSN:

1680-7316

Date made live:

21 May 2014 12:43 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/507280