HO2NO2 and HNO3 in the coastal Antarctic winter night: A "lab-in-the-field" experiment

Jones, A.E. ORCID: https://orcid.org/0000-0002-2040-4841; Brough, N. ORCID: https://orcid.org/0000-0002-2316-5292; Anderson, P.S.; Wolff, E.W.. 2014 HO2NO2 and HNO3 in the coastal Antarctic winter night: A "lab-in-the-field" experiment. Atmospheric Chemistry and Physics, 14. 11843-11851. 10.5194/acp-14-11843-2014

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Abstract/Summary

Observations of peroxynitric acid (HO2NO2) and nitric acid (HNO3) were made during a 4 month period of Antarctic winter darkness at the coastal Antarctic research station, Halley. Mixing ratios of HNO3 ranged from instrumental detection limits to ∼8 parts per trillion by volume (pptv), and of HO2NO2 from detection limits to ∼5 pptv; the average ratio of HNO3 : HO2NO2 was 2.0(± 0.6):1, with HNO3 always present at greater mixing ratios than HO2NO2 during the winter darkness. An extremely strong association existed for the entire measurement period between mixing ratios of the respective trace gases and temperature: for HO2NO2, R2 = 0.72, and for HNO3, R2 = 0.70. We focus on three cases with considerable variation in temperature, where wind speeds were low and constant, such that, with the lack of photochemistry, changes in mixing ratio were likely to be driven by adsorption/desorption mechanisms alone. We derived enthalpies of adsorption (ΔHads) for these three cases. The average ΔHads for HNO3 was −42 ± 7 kJ mol−1 and for HO2NO2 was −56 ± 3 kJ mol−1; these values are extremely close to laboratory-derived values. This exercise demonstrates (i) that adsorption to/desorption from the snow pack should be taken into account when addressing budgets of boundary layer HO2NO2 and HNO3 at any snow-covered site, and (ii) that Antarctic winter can be used as a~natural "laboratory in the field" for testing data on physical exchange mechanisms.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.5194/acp-14-11843-2014
Programmes:	BAS Programmes > Polar Science for Planet Earth (2009 - ) > Chemistry and Past Climate
ISSN:	1680-7316
Date made live:	09 Jul 2014 13:37 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/507140

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.5194/acp-14-11843-2014

Programmes:

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

ISSN:

1680-7316

Date made live:

09 Jul 2014 13:37 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/507140