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| Titel |
Vertical electron density and topside effective scale height (HT) variations over the Indian equatorial and low latitude stations |
| VerfasserIn |
K. Venkatesh, P. V. S. Rama Rao, P. L. Saranya, D. S. V. V. D. Prasad, K. Niranjan |
| 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 ; 29, no. 10 ; Nr. 29, no. 10 (2011-10-24), S.1861-1872 |
| Datensatznummer |
250017111
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| Publikation (Nr.) |
 copernicus.org/angeo-29-1861-2011.pdf |
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| Zusammenfassung |
Understanding the vertical electron density profile, which is the
altitudinal variation of ionospheric electron density distribution is an
important aspect for the ionospheric investigations. In this paper, the
bottom-side electron density profiles derived from ground based ionosonde
data and the ROCSAT-1 in-situ electron density data were used to determine
the estimates of the topside electron density profiles using α-Chapman function
over an equatorial station Trivandrum (8.47° N,
76.91° E) and a low latitude station Waltair (17.7° N, 83.3° E)
in the Indian region. The reconstructed electron density profiles are
compared with IRI (2007) model derived vertical electron density profiles
which resulted in significant deviations between the two different profiles.
Both the reconstructed electron density profiles and the IRI model derived
profiles are integrated independently to derive the Total Electron Content
(TEC) values which are compared with GPS derived TEC values. TEC values
derived from the reconstructed electron density profiles give better
estimates with the GPS-TEC compared to those of IRI model derived TEC
values. Compared to the GPS-TEC, the IRI model is underestimating the TEC
values during day-time and is overestimating during night-time at both the
stations. The percentage deviations of IRI derived TEC from GPS-TEC are
larger compared to those between reconstructed profile derived TEC and
GPS-TEC.
F2-layer peak electron density, peak height and electron density at
ROCSAT altitudes (≈600 km) are used to derive the effective scale
heights (HT) of the topside ionosphere during the period from July 2003
to June 2004. The diurnal and seasonal variations of HT and E×B drift
velocities are presented in this paper. The diurnal variation of the
effective scale height (HT) shows peak values around noon hours with
higher values during day-time and lower values during night-time both at
Trivandrum and Waltair. The E×B drift velocities at both the places also
have shown a clear diurnal variation with a negative peak around 04:00 LT and maximum during
day-time hours. The higher and lower values of HT seem to be associated
with positive and negative phases of the E×B drift
velocities, respectively. |
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