On the equinoctial asymmetry in the threshold height for the occurrence of equatorial spread F

Abstract
<p>In the present study, the threshold height (<em>h</em> F<sub>c</sub>) for ESF occurrence irrespective of the polarity of the meridional winds during vernal and autumnal equinoxes is investigated using a large database spread over 1993\textendash2008. The characteristics of the thermosphere during the two equinoxes have also been examined using TIMED/GUVI O/N2 data. The major aspects that have emerged are (i) presence of significant equinoctial asymmetry in<em>h</em> F<sub>c</sub>\&nbsp;for the years examined, (ii) increase in the equinoctial asymmetry of\&nbsp;<em>h</em> F<sub>c</sub>\&nbsp;with solar activity, (iii) presence of significant asymmetry in O/N<sub>2</sub>\&nbsp;and TIEGCM simulations of normalized atomic oxygen mass density, between the two equinoxes.</p>
Year of Publication
2015
Journal
Journal of Atmospheric and Solar-Terrestrial Physics
Volume
124
Number of Pages
59-62
Date Published
03/2015
ISSN Number
13646826
URL
http://www.sciencedirect.com/science/article/pii/S1364682615000103
DOI
10.1016/j.jastp.2015.01.008