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Titel |
The lunar tide in sporadic E |
VerfasserIn |
R. J. Stening |
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 ; 17, no. 10 ; Nr. 17, no. 10, S.1344-1351 |
Datensatznummer |
250013828
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Publikation (Nr.) |
copernicus.org/angeo-17-1344-1999.pdf |
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Zusammenfassung |
It seems that the wind shear theory is
accepted for the explanation of sporadic E at mid and low latitudes. Some
examples from Arecibo are displayed to show this. The effect of lunar tides
should then modify the wind-shear theory in a manner that yields the observed
features of the lunar tide in the critical frequency foEs and the height
h'Es of the sporadic E. This is shown to imply that the phase of the lunar tide
in h'Es should be the same as the phase of the lunar tide in the eastward wind
and that the phase of the lunar tide in foEs is three hours later. Hourly
values of foEs, f bEs (the blanketing critical frequency) and h'Es
from several observatories are analysed for the lunar semidiurnal tide. It is
found that the phase of the tide in foEs is often about 3 hours later
than for h'Es in agreement with the theory. Seasonal variations in the tide are
also examined with the statistically most significant results (largest
amplitudes) usually occurring in summer. After reviewing the many difficulties
associated with determining the lunar tide in Es, both experimentally and
theoretically, the analysed phase results are compared with what might be
expected from Hagan's global scale wave model. Agreement is only fair (a success
rate of 69% among the cases examined) but probably as good as might be expected.
Key words. Ionosphere (ionosphere – atmosphere
interactions – ionospheric irregularities), Meteorology and atmosphere
dynamics (waves and tides) |
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