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Indian Journal of Radio & Space Physics (IJRSP) >
IJRSP Vol.41 [2012] >
IJRSP Vol.41(2) [April 2012] >
| Title: | COSMIC observations of ionospheric density profiles over Indian region: Ionospheric conditions during extremely low solar activity period |
| Authors: | Sripathi, S |
| Keywords: | Electron density, Equatorial ionization anomaly (EIA)
Equatorial electrojet (EEJ) strength
Ionospheric density
Equinoctial asymmetry |
| Issue Date: | Apr-2012 |
| Publisher: | NISCAIR-CSIR, India |
| PACS No.: | 94.20.dt; 94.20.dv |
| Abstract: | In the present paper, for the first time, an attempt has been made to study
the seasonal, altitudinal, diurnal and latitudinal variation of low latitude
electron density obtained using COSMIC radio occultation (RO) measurements over
Indian longitudes during the deep solar minimum year 2008. The seasonal
variation shows enhanced electron densities at vernal and autumn equinoxes
compared to winter and summer seasons. The observations also suggest a shift in
the time and altitude at which the peak of the electron density occurs in
different seasons. An important finding is that there exists an equinoctial
asymmetry in the electron density with respect to altitude and latitude, where
the electron density is higher at vernal equinox compared to autumn equinox.
The latitudinal and seasonal variation of peak electron density (NmF2)
during 10:00-14:00 hrs LT indicate enhanced equatorial ionization anomaly (EIA)
on either side of the magnetic equator at both vernal and autumn equinoxes
compared to the other seasons. Seasonal variation of equatorial electrojet
(EEJ) strength obtained from geomagnetic H-field variations also shows strong
EEJ at vernal and autumn equinoxes indicating that EEJ strength indeed partly controls
the EIA development. Further, the results indicate that NmF2
over the northern EIA crest region is correlated well with solar flux. |
| Page(s): | 98-109 |
| CC License: |  CC Attribution-Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-105X (Online); 0367-8393 (Print) |
| Source: | IJRSP Vol.41(2) [April 2012]
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