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| Titel |
Variability of ionospheric scintillation near the equatorial anomaly crest of the Indian zone |
| VerfasserIn |
S. Chatterjee, S. K. Chakraborty |
| 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 ; 31, no. 4 ; Nr. 31, no. 4 (2013-04-19), S.697-711 |
| Datensatznummer |
250019026
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| Publikation (Nr.) |
 copernicus.org/angeo-31-697-2013.pdf |
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| Zusammenfassung |
| Multistation observations of ionosphere scintillation at VHF (250 MHz) and
GNSS L1 frequency from three locations – (i) Bokkhali (BOK) (geographic
21.6° N, 88.2° E, dip 31.48°, (ii) Raja Peary Mohan College
Centre (RPMC) (geographic 22.66° N, 88.4° E, dip 33.5°) and
(iii) Krishnath College Centre (KNC), Berhampore (geographic 24.1° N,
88.3° E, dip 35.9°) – at ~ 1° latitudinal
separations near the northern crest of the equatorial ionization anomaly (EIA)
of the Indian longitude sector are investigated in conjunction with total
electron content (TEC) data and available ionosonde data near the magnetic
equator to study fine structure in spatial and temporal variability patterns
of scintillation occurrences. The observations are carried out in the
autumnal equinoctial months of a high solar activity year (2011). In spite of
smaller latitudinal/spatial separation among the observing stations,
conspicuous differences are reflected in the onset time, duration, fade rate
and fade depth of VHF scintillations as well as in spectral features.
Scintillations are mostly associated with depletion in TEC around the
anomaly crest and occurrence of ESF near the magnetic equator at an earlier
time. Not only the strength of EIA, but also the locations of observing
stations with respect to the post-sunset resurgence peak of EIA seem to play
dominant role in dictating the severity of scintillation activity. A
secondary enhancement in diurnal TEC in the post-sunset period seems to
accentuate the irregularity activities near the anomaly crest, and a
threshold value of the same may fruitfully be utilized for the prediction of
scintillation around the locations. An idea regarding latitudinal extent of
scintillation is developed by considering observations at L1 frequency from
the GPS and GLONASS constellation of satellites. A critical value of
h'F near the magnetic equator for the occurrence of
simultaneous scintillation at the three centres is suggested. The
observations are discussed considering electrodynamical aspect of equatorial
irregularities. |
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