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

Abstract

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.

Electrodynamic disturbances in the Brazilian equatorial and low‐latitude ionosphere on St. Patrick's Day storm of 17 March 2015

“…The additional stratification of F 3 layer due to PPEF in the dayside equatorial region has been observed earlier by Balan et al [2008] andTulasi Ram et al [2012]. The F 3 layer occurrence characteristics during storm time and their comparison with those of quiet time are reported by Batista et al [2017]. The enhanced electric fields transport the equatorial plasma vertically upward; however, Brazilian sector being in dayside, the ion production viz photoionization continuously occurs at F region base around 200 km.…”

Superfountain Effect Linked With 17 March 2015 Geomagnetic Storm Manifesting Distinct F3 Layer

“…Balan et al () have shown the F 3 layer occurrence at three stations spanning from the equator to southern low‐latitudes of 11.6°S. Later, Batista et al () presented the F 3 layer occurrence at two conjugate stations at 9.7°N and 13.3°S dip latitudes. In general, the F 3 layer occurrences over equatorial latitudes during storm times are explained due to rapid uplift of F layer by eastward PPEF owing to the southward turning of IMF B z .…”

Global Longitudinal Behavior of IRI Bottomside Profile Parameters From FORMOSAT‐3/COSMIC Ionospheric Occultations

“…Under normal E × B vertical drift and usual photochemical and dynamical processes, the northward EMW during winter pushes the plasma upward along the magnetic field lines at the Southern Hemisphere preventing effective diffusion process and retaining part of the ionization at higher altitudes to result in higher B0 closer to the magnetic equator in the Southern Hemisphere. Oppositely, the southward EMW during summer pushes the plasma upward along the magnetic field lines at the Northern Hemisphere to manifest higher B0 nearer to the magnetic equator in the Northern Hemisphere (Balan et al, ; Batista et al, ; Tulasi Ram, Su, & Liu, ). During equinox, the transequator EMW is incompetent and hence regular equatorial phenomena control the double crest structure in B0 that is barely noticed only during LSA equinox and disappears during HSA equinox in our study.…”