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| Titel |
The effects of nitric oxide cooling and the photodissociation of molecular oxygen on the thermosphere/ionosphere system over the Argentine Islands |
| VerfasserIn |
G. D. Wells, A. S. Rodger, R. J. Moffett, G. J. Bailey, T. J. Fuller-Rowell |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 15, no. 3 ; Nr. 15, no. 3, S.355-365 |
| Datensatznummer |
250012671
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| Publikation (Nr.) |
 copernicus.org/angeo-15-355-1997.pdf |
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| Zusammenfassung |
| In the past the global, fully coupled,
time-dependent mathematical model of the Earth's thermosphere/ionosphere/plasmasphere
(CTIP) has been unable to reproduce accurately observed values of the maximum
plasma frequency, foF2, at extreme geophysical locations such as the
Argentine Islands during the summer solstice where the ionosphere remains in
sunlight throughout the day. This is probably because the seasonal dependence of
thermospheric cooling by 5.3 µm nitric oxide has been neglected and the
photodissociation of O2 and heating rate calculations have been
over-simplified. Now we have included an up-to-date calculation of the solar EUV
and UV thermospheric heating rate, coupled with a new calculation of a diurnally
varying O2 photodissociation rate, in the model. Seasonally dependent
5.3 µm nitric oxide cooling is also included. With these important
improvements, it is found that model values of foF2 are in substantially
better agreement with observation. The height of the F2-peak is reduced
throughout the day, but remains within acceptable limits of values derived from
observation, except at around 0600 h LT. We also carry out two studies of the
sensitivity of the upper atmosphere to changes in the magnitude of nitric oxide
cooling and photodissociation rates. We find that hmF2 increases with increased
heating, whilst foF2 falls. The converse is true for an increase in the
cooling rate. Similarly increasing the photodissociation rate increases both
hmF2 and foF2. These changes are explained in terms of changes in the
neutral temperature, composition and neutral wind. |
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