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| Titel |
Radar Observations of 8.3-m scale equatorial spread F irregularities over Trivandrum |
| VerfasserIn |
D. Tiwari, A. K. Patra, C. V. Devasia, R. Sridharan, N. Jyoti, K. S. Viswanathan, K. S. V. Subbarao |
| 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 ; 22, no. 3 ; Nr. 22, no. 3 (2004-03-19), S.911-922 |
| Datensatznummer |
250014811
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| Publikation (Nr.) |
 copernicus.org/angeo-22-911-2004.pdf |
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| Zusammenfassung |
In this paper, we present observations of equatorial spread F (ESF) irregularities made
using a newly installed 18MHz radar located at Trivandrum. We characterize the morphology
and the spectral parameters of the 8.3-m ESF irregularities which are found to be remarkably
different from that observed so extensively at the 3-m scale size. We also present statistical results
of the irregularities in the form of percentage occurrence of the echoes and spectral parameters
(SNR, Doppler velocity, Spectral width). The Doppler spectra are narrower, less structured and
less variable in time as compared to those observed for 3-m scale size. We have never observed
the ESF irregularity velocities to be supersonic here unlike those at Jicamarca, and the
velocities are found to be within ±200ms–1. The spectral widths are found to be
less than 150ms–1. Hence, the velocities and spectral width both are smaller than those reported for 3-m scale
size. The velocities and spectral widths are further found to be much smaller than those of the
American sector. These observations are compared with those reported elsewhere and
discussed in the light of present understanding on the ESF irregularities at different
wavelengths.
Key words. Ionoshphere (equatorial ionosphere, plasma
waves and instabilities; ionospheric irregularities) |
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