A model study of the temporal behaviour of the emission intensity and rotational temperature of the OH Meinel bands for high-latitude summer conditions

Autor: M. J. López-González, D. P. Murtagh, P. J. Espy, J. J. López-Moreno, R. Rodrigo, G. Witt
Jazyk: angličtina
Rok vydání: 1996
Předmět:
Zdroj: Annales Geophysicae, Vol 14, Pp 59-67 (1996)
Druh dokumentu: article
ISSN: 0992-7689
1432-0576
DOI: 10.1007/s00585-996-0059-x
Popis: The temporal variation of OH* emission and weighted rotational temperature has been studied for high-latitude summer conditions. Observations for 60°N latitude show OH weighted temperatures that always exceed 145 K even during periods of noctilucent clouds. Using a one-dimensional model the effects in excited OH concentration produced by changes in temperature, eddy diffusion, and water concentration have been analysed. We are forced to conclude that there remains a discrepancy between the OH temperatures predicted by the model and that obtained from OH* measurements. An increase in OH* concentration from June to the beginning of August, followed by a slow decrease during August has been obtained in agreement with the measurements. The 16-day modulation present in the measurements was simulated in a simple manner by varying the temperature in the mesopause region. This variation produces periodic modulations in both OH* concentration and weighted temperature of 16 days. The results show the temperature leading the OH* column concentration by three days. This phase shift is also present in the observations.
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