Effects of meridional winds on the interhemispheric asymmetry of the equatorial ionization anomaly on the Africa sector over 3 years during both quiet and disturbed conditions

Abstract:

Observations made by the Langmuir probes on board the SWARM satellites and the Fabry-
Perot interferometer (FPI) installed at the Oukaimeden Observatory in Morocco have been
systematically analyzed to find the effect of geomagnetic activity on the thermosphere-
ionosphere system and the coupling between the two layers over 3 years from 2014 to 2016.
Annual and seasonal variations of the electron density in the low- and mid-latitude topside
ionosphere at different local time sectors show a symmetry of the annual average of the
equatorial ionization anomaly (EIA) from 12 LT to 00 LT and an asymmetry in the other local
time sectors with a denser crest in the northern hemisphere. Observations show strong
seasonal variations, with the electron density being lower around the June solstice compared
to the rest of the year. From 41 disturbed nights (with SYM-H<-50nT, Kp>5) we identified
and analyzed, we have classified the effect of the storm time meridional neutral winds on EIA
crests into two types of variation. Moreover, very low values of electron density, at times
lower than 5×10 3 cm -3 , are observed during disturbed conditions. Finally, we have quantified
the relations between the FPI data, the EIA, and HWM model results, during both quiet and
disturbed conditions.