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Ann. Geophys., 22, 1549-1561, 2004
www.ann-geophys.net/22/1549/2004/
© European Geosciences Union 2004
Determining rotational temperatures from the OH(8-3) band, and a comparison with OH(6-2) rotational temperatures at Davis, Antarctica
F. Phillips1, G. B. Burns1, W. J. R. French1, P. F. B. Williams1, A. R. Klekociuk1, and R. P. Lowe2
1Australian Antarctic Division, Kingston 7050, Tasmania, Australia
2Department of Physics and Astronomy, University of Western Ontario, London N6A3K7, Canada
Abstract. Rotational temperatures derived from the OH(8–3) band may vary by ~18K depending
on the choice of transition probabilities. This is of concern when absolute
temperatures or trends determined in combination with measurements of other
hydroxyl bands are important. In this paper, measurements of the
OH(8–3) temperature-insensitive Q/P and R/P line intensity ratios are used to select the most
appropriate transition probabilities for use with this band. Aurora, airglow and solar
and telluric absorption in the OH(8–3) band are also investigated. Water vapour
absorption of P1(4), airglow or auroral contamination of P1(2) and solar absorption in
the vicinity of P1(5) are concerns to be considered when deriving rotational
temperatures from this band.
A comparison is made of temperatures derived from OH(6–2) and OH(8–3) spectra
collected alternately at Davis (69° S, 78° E) in 1990. An average difference of ~4K is
found, with OH(8–3) temperatures being warmer, but a difference of this magnitude is
within the two sigma uncertainty limit of the measurements.
Key words. Atmospheric composition and structure airglow
and aurora; pressure, density, and temperature)
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