Influence of Geomagnetic Storms on Ionospheric F2-Layer at Low and Mid Latitudes in 300° E Meridian

Resumo

The behaviour of the ionospheric F₂-layer during geomagnetic storm is studied using the critical frequency parameter f_oF₂. The magnetic storms of 2nd October 2013 and 22nd June 2015 are considered. The variations of f_oF₂ at Millstone Hill (42.6° N, 288.5° E), Ramey (18.5° N, 292.9° E), Boa Vista (2.8° N, 299.3° E) and Port Stanley (51.6° S, 302.1° E) along the longitude of about 300° E are analysed. The main observations of this study are (1) strong and short term positive storm effects are observed at the beginning of recovery phase for the moderate storm at all the stations and during the main phase for the intense storm at Millstone Hill and Port Stanley, (2) long term negative phase is observed at the northern hemispheric stations for the intense storm and (3) the southern winter hemisphere station Port Stanley recorded positive storm effects during the main and recovery phases of the intense storm on 22-06-2015. The observed deviations in f_oF₂ are discussed in terms of Prompt Penetration Electric Fields, Disturbance Dynamo Electric Fields, Disturbance neutral winds and Travelling Atmospheric Disturbance.