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Indian Journal of Radio & Space Physics (IJRSP) >
IJRSP Vol.41 [2012] >
IJRSP Vol.41(2) [April 2012] >
| Title: | On the variability of the observed HF Doppler derived equatorial F-region plasma drifts during evening and morning hours and the chemical corrections therein |
| Authors: | Sumod, S G
Pant, T K
Nayar, S R P |
| Keywords: | Vertical plasma drift
Equatorial ionosphere
Ionospheric chemistry
F-region plasma drift |
| Issue Date: | Apr-2012 |
| Publisher: | NISCAIR-CSIR, India |
| PACS No.: | 94.20.dj; 94.20.wc |
| Abstract: | The radar derived F-region vertical plasma
drift measurements, especially during evening/morning hours are apparent mainly
because of the additional contribution from photochemical loss and/or
production. As a consequence, it is very important to delineate the role of
chemistry from these drift measurements in order to have a meaningful/realistic
interpretation of the actual movement of the plasma in the ionosphere. In this
paper, two chemical schemes have been employed separately for evening and
morning hours to estimate the apparent drifts produced solely due to the
chemistry. This study has been carried out by taking into account the important
chemical reactions over equator during these times and for the computation, the
neutral density of N2, O2, and neutral temperature Tn
have been obtained from the Mass Spectrometer and Incoherent Scatter (MSIS)
model. The temporal, altitudinal and seasonal variations of the chemical
contributions have been theoretically estimated. The observed F-region vertical
plasma drift measurements obtained from a multi-frequency HF Doppler radar over
Trivandrum (8.5°N, 77°E, 0.5°N dip latitude) are then corrected, by taking into
account the reflection height variation. The study reveals that (i) the
apparent drift due to chemistry is strongly altitude dependent and can indeed
be as high as 10-15 m
s-1; (ii) there is a clear cut seasonal pattern for these correction
factors with a northern hemispheric (NH) summer (June) minima and a maxima
during the NH winter solstice (December). |
| Page(s): | 130-140 |
| 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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