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Titel |
Geomagnetic control of polar mesosphere summer echoes |
VerfasserIn |
J. Bremer, P. Hoffmann, T. L. Hansen |
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 ; 18, no. 2 ; Nr. 18, no. 2, S.202-208 |
Datensatznummer |
250013908
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Publikation (Nr.) |
copernicus.org/angeo-18-202-2000.pdf |
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Zusammenfassung |
Using observations with the ALOMAR SOUSY
radar near Andenes (69.3°N, 16.0°E) from 1994 until 1997 polar mesosphere
summer echoes (PMSE) have been investigated in dependence on geomagnetic K
indices derived at the Auroral Observatory Tromsø (69.66°N, 18.94°E). During
night-time and morning hours a significant correlation between the
signal-to-noise ratio (SNR) of the radar results and the geomagnetic K indices
could be detected with a maximum correlation near midnight. The correlation
becomes markedly smaller in the afternoon and early evening hours with a minimum
near 17 UT. This diurnal variation is in reasonable agreement with riometer
absorption at Ivalo (68.55°N, 27.28°E) and can be explained by the diurnal
variation of ionization due to precipitating high energetic particles.
Therefore, a part of the diurnal PMSE variation is caused by this particle
precipitation. The variability of the solar EUV variation, however, has no
significant influence on the PMSE during the observation period.
Keywords: Ionosphere (auroral ionosphere) -
Magnetospheric physics (energetic particles, precipitating) - Radio science
(remote sensing) |
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