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| Titel |
A first comparison of irregularity and ion drift velocity measurements in the E-region |
| VerfasserIn |
R. A. Makarevich, F. Honary, V. S. C. Howells, A. V. Koustov, S. E. Milan, J. A. Davies, A. Senior, I. W. McCrea, P. L. Dyson |
| 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 ; 24, no. 9 ; Nr. 24, no. 9 (2006-09-20), S.2375-2389 |
| Datensatznummer |
250015633
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| Publikation (Nr.) |
 copernicus.org/angeo-24-2375-2006.pdf |
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| Zusammenfassung |
| E-region irregularity velocity measurements at large flow angles
with the STARE Finland coherent VHF radar are considered in
context of the ion and electron velocity data provided by the
EISCAT tristatic radar system, CUTLASS Finland coherent HF radar,
and IMAGE fluxgate magnetometers. The data have been collected
during a special experiment on 27 March 2004 during which EISCAT
was scanning between several E- and one F-region altitudes along
the magnetic field line. Within the E-region, the EISCAT
measurements at two altitudes of 110 and 115 km are considered
while the electron velocity is inferred from the EISCAT ion
velocity measurements at 278 km. The line-of-sight (l-o-s) VHF
velocity measured by STARE VHF los is compared to the ion
and electron velocity components (Vi0 comp and
Ve0 comp) along the STARE l-o-s direction. The comparison with
Ve0 comp for the entire event shows that the measurements
exhibit large scatter and small positive correlation. The
correlation with Ve0 comp was substantial in the first half
of the interval under study when Ve0 comp was larger in
magnitude. The comparison with Vi0 comp at 110 and 115 km
shows a considerable positive correlation, with VHF velocity being
typically larger (smaller) in magnitude than Vi0 comp at
110 km (115 km) so that VVHF los appears to be bounded by
the ion velocity components at two altitudes. It is also
demonstrated that the difference between VVHF los and
Vi0 comp at 110 km can be treated, in the first approximation, as
a linear function of the effective backscatter height heff
also counted from 110 km; heff varies in the range 108–114 km
due to the altitude integration effects in the scattering
cross-section. Our results are consistent with the notion that VHF
velocity at large flow angles is directly related to the ion drift
velocity component at an altitude heff. |
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