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| Titel |
Statistical analysis of radar observed F region irregularities from three longitudinal sectors |
| VerfasserIn |
R. Y. C. Cueva, E. R. de Paula, A. E. Kherani |
| 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. 12 ; Nr. 31, no. 12 (2013-12-03), S.2137-2146 |
| Datensatznummer |
250086156
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| Publikation (Nr.) |
 copernicus.org/angeo-31-2137-2013.pdf |
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| Zusammenfassung |
| Equatorial Spread F (ESF) is a manifestation of ionospheric interchange
instabilities in the nighttime equatorial F region. These instabilities
generate plasma density irregularities with scale sizes ranging from
centimetres to thousands of kilometres. The irregularities can be detected
from a variety of instruments such as digisonde, coherent and incoherent
scatter radars, in situ space probes, and airglow photometers. In the present
study, occurrence statistics of the ESF, based on various parameters are
presented using data obtained from the VHF radars located at three
longitudinally separated equatorial stations: Christmas Island (2° N,
202.6° E, 2.9° N dip latitude), São Luís
(2.59° S, 315.8° E, 0.5° S dip latitude) and
Jicamarca (12° S, 283.1° E, 0.6° N dip latitude). The
ESF parameters presented here are the onset altitude, onset time (onset
refers to first appearance of signal in the radar field of view) of the
bottom-type and plume, and the peak altitude of the plume. Recent studies
have used these parameters to classify the spread F occurrence
characteristics. The present study reveals novel features namely, the
dependence of ESF parameters on the seasonal, solar flux, declination angle
and longitudinal dependence from the three radar sites. In addition, we also
present an empirical model to determine the nature of these ESF parameters as
a function of the solar flux which may enable us to forecast (with 30 min to
1 h tolerance) the plume occurrence at any longitude located in between
São Luís and Christmas Island. |
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