Anomalous Responses of the F₂ Layer Over the Brazilian Equatorial Sector During a Counter Electrojet Event: A Case Study

Abstract

The day-to-day variability in the ionosphere is a phenomenon that is directly connected to the internal and external processes that modify the structure of the atmosphere-ionosphere-magnetosphere (AIM) system, such as internal atmospheric waves (gravity, planetary, tidal, and acoustic waves) that propagate to the ionosphere from the lower height regions (see e.

Ionospheric Variability over the Brazilian Equatorial Region during the Minima Solar Cycles 1996 and 2009: Comparison between Observational Data and the IRI Model

“…In agreement with these authors, large modifications in the F 1 and F 2 layers were noticed, in the form of bifurcations and forking traces in both F 1 and F 2 layers, besides other modifications that were not very well defined. For the same period [38] also showed an anomalous case in June 2009, in which the ionospheric F 2 layer trace over SL appeared to have "broken in half" making it appear that the first part of the F 2 layer (at the lower frequency region) was thrown down whilst the upper part of the trace remained at higher altitudes. In agreement with these papers, all of these features were attributed to a possible manifestation of gravity waves.…”