F3 layer development during quiet and disturbed periods as observed at conjugate locations in Brazil: The role of the meridional wind

• Published in: Journal of geophysical research. Space physics 2017-02, Vol.122 (2), p.2361-2373
• Main Authors: Batista, Inez S., Candido, C. M. N., Souza, J. R., Abdu, M. A., Araujo, R. C., Resende, L. C. A., Santos, A. M.
• Format: Article
• Language: English
• Subjects: B0 thickness parameter; Conjugate points; Equator; equatorial ionosphere; F region; F3 layer; Geodetics; Geomagnetism; Geophysical data; Geophysics; ionosonde; Latitude; low latitude electrodynamics; Magnetic equator; Meridional wind; Northern Hemisphere; Plasma drift; Solstices; Southern Hemisphere; thermospheric meridional wind; Vertical drift; Wind; Wind effects
• ISSN: 2169-9380; 2169-9402
• DOI: 10.1002/2016JA023724

In this work we use ionospheric data from two low‐latitude stations located north and south of the geomagnetic equator, at approximately the same magnetic longitude, in order to study the occurrence of the F3 layer. The location of the stations being at almost geomagnetically conjugate points is such that the effects of the electric field/vertical plasma drift and diffusion will be almost symmetric around the magnetic equator. Under this configuration it is possible to deduce the effect of meridional wind in the F3 layer occurrence. Our results show that during the December solstice the layer will be present at the Southern Hemisphere (SH) location in 97% of the days and in the Northern Hemisphere (NH) location in only 4% of the days. In the June solstice the situation is reversed with the occurrence in the NH being 82% and 16% in the SH. For the March equinox the occurrence is low at both locations (4% in NH and 7% in SH), being mainly present during magnetically disturbed periods. The analysis of the effective meridional wind based on the Horizontal Wind Model and on the asymmetry of the F layer peak height observed at the two locations confirms the ubiquitous role of the wind in the F3 layer formation and/or persistence during both quiet and disturbed periods. The B0 parameter, that is a measure of the thickness of the bottomside F region profile, revealed to be a good proxy for the F3 layer occurrence. Key Points The B0 thickness parameter is a good proxy to describe the F3 occurrence at the low‐latitude locations Effective meridional wind toward the equator is a necessary condition for F3 layer formation during quiet periods During disturbed periods the F3 layer will last longer at the hemisphere under the condition of equatorward effective meridional wind