Atmos. Chem. Phys. Discuss., 9, 837-863, 2009
www.atmos-chem-phys-discuss.net/9/837/2009/
doi:10.5194/acpd-9-837-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Variability and trends in stratospheric NO2 in Antarctic summer, and implications for the Brewer-Dobson circulation
P. A. Cook and H. K. Roscoe
British Antarctic Survey, Madingley Rd, Cambridge CB3 0ET, UK

Abstract. NO2 measurements during 1990–2007, obtained from a zenith-sky spectrometer in the Antarctic, are analysed to determine the long-term changes. The changes in midsummer should be indicative of any changes in the Brewer-Dobson circulation. An atmospheric photochemical box model and a radiative transfer model are used to improve the accuracy of determination of the vertical columns from the slant column measurements, and to deduce the amount of NOy from NO2. We find that the NO2 and NOy columns in midsummer have large inter-annual variability superimposed on a broad maximum in 2000, with little overall trend over the full time period. These changes are robust to a variety of alternative settings when determining vertical columns from slant columns or determining NOy from NO2. They suggest similar changes in speed of the Brewer-Dobson circulation but with opposite sign, i.e. a broad minimum around 2000.

Citation: Cook, P. A. and Roscoe, H. K.: Variability and trends in stratospheric NO2 in Antarctic summer, and implications for the Brewer-Dobson circulation, Atmos. Chem. Phys. Discuss., 9, 837-863, doi:10.5194/acpd-9-837-2009, 2009.
 
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