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Direct observations of nitric oxide produced by energetic electron precipitation into the Antarctic middle atmosphere

Newnham, David; Espy, Patrick J.; Clilverd, Mark; Rodger, Craig J.; Seppala, Annika; Maxfield, David; Hartogh, Paul; Holmen, Kim; Horne, Richard. 2011 Direct observations of nitric oxide produced by energetic electron precipitation into the Antarctic middle atmosphere. Geophysical Research Letters, 38 (L20104). 5, pp. 10.1029/2011GL048666

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Abstract/Summary

We report the first ground-based passive microwave observations made from Troll station, Antarctica, which show enhanced mesospheric nitric oxide (NO) volume mixing ratio reaching levels of 1.2 ppmv, or 2–3 orders of magnitude above background, at 70–80 km during small, relatively isolated geomagnetic storms in 2008. The mesospheric NO peaked 2 days after enhanced NO at higher altitudes (110–150 km) measured by the SABER satellite, and 2 days after peaks in the >30 keV and >300 keV electron flux measured by POES, although the 300 keV electron flux remained high. High time resolution data shows that mesospheric NO was enhanced at night and decayed during the day and built up to high levels over a period of 3–4 days. The altitude profile of mesospheric NO suggests direct production by ∼300 keV electron precipitation. Simulations using the Sodankylä Ion and Neutral Chemistry model show that the delay between thermospheric and mesospheric NO enhancements was primarily a result of the weaker production rate at lower altitudes by ∼300 keV electrons competing against strong day-time losses.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1029/2011GL048666
Programmes: BAS Programmes > Polar Science for Planet Earth (2009 - ) > Climate
ISSN: 0094-8276
NORA Subject Terms: Atmospheric Sciences
Date made live: 24 Nov 2011 10:54
URI: http://nora.nerc.ac.uk/id/eprint/15956

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