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| Titel |
Climatology of GPS phase scintillation at northern high latitudes for the period from 2008 to 2013 |
| VerfasserIn |
P. Prikryl, P. T. Jayachandran, R. Chadwick, T. D. Kelly |
| 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 ; 33, no. 5 ; Nr. 33, no. 5 (2015-05-13), S.531-545 |
| Datensatznummer |
250121195
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| Publikation (Nr.) |
 copernicus.org/angeo-33-531-2015.pdf |
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| Zusammenfassung |
| Global positioning system scintillation and total electron content (TEC) data have
been collected by ten specialized GPS Ionospheric Scintillation and TEC
Monitors (GISTMs) of the Canadian High Arctic Ionospheric Network (CHAIN).
The phase scintillation index σΦ is obtained from the phase of the L1 signal sampled at 50 Hz. Maps of phase scintillation occurrence as a
function of the altitude-adjusted corrected geomagnetic (AACGM)
latitude and
magnetic local time (MLT) are computed for the period from 2008 to 2013.
Enhanced phase scintillation is collocated with regions that are known as
ionospheric signatures of the coupling between the solar wind and
magnetosphere. The phase scintillation mainly occurs on the dayside in the
cusp where ionospheric irregularities convect at high speed, in the
nightside auroral oval where energetic particle precipitation causes
field-aligned irregularities with steep electron density gradients and in
the polar cap where electron density patches that are formed from a tongue
of ionization. Dependences of scintillation occurrence on season, solar and
geomagnetic activity, and the interplanetary magnetic field (IMF)
orientation are investigated. The auroral phase scintillation shows
semiannual variation with equinoctial maxima known to be associated with
auroras, while in the cusp and polar cap the scintillation occurrence is
highest in the autumn and winter months and lowest in summer. With rising solar and
geomagnetic activity from the solar minimum to solar maximum, yearly maps of
mean phase scintillation occurrence show gradual increase and expansion of
enhanced scintillation regions both poleward and equatorward from the
statistical auroral oval. The dependence of scintillation occurrence on the
IMF orientation is dominated by increased scintillation in the cusp,
expanded auroral oval and at subauroral latitudes for strongly southward
IMF. In the polar cap, the IMF BY polarity controls dawn–dusk
asymmetries in scintillation occurrence collocated with a tongue of ionization
for southward IMF and with sun-aligned arcs for northward IMF. In investigating
the shape of scintillation-causing irregularities, the distributions of
scintillation occurrence as a function of "off-meridian" and "off-shell"
angles that are computed for the receiver–satellite ray at the ionospheric
pierce point are found to suggest predominantly field-aligned irregularities in the
auroral oval and L-shell-aligned irregularities in the cusp. |
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