Effects of the intense geomagnetic storm of September−October 2012 on the equatorial, low and mid-latitude F region in the American and African sector during the unusual 24th solar cycle

R. DE JESUS; P.R. FAGUNDES; A.J. COSTER; BOLAJI, O. S.; J.H.A. SOBRAL; I.S. BATISTA; A.J. DE ABREU; VENKATESH, K.; M. GENDE; J.R. ABALDE; S.G. SUMOD

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS

Elsevier

Año: 2016 vol. 138 p. 93 - 105

1364-6826

The mainpurposeofthispaperistoinvestigatetheresponseoftheionosphericFlayerintheAmericanand Africansectorsduringtheintensegeomagneticstormwhichoccurredon30September?01October2012.Inthiswork,weusedobservationsfromachainof20GPSstationsintheequatorial,low-andmid-latitude regionsintheAmericanandAfricansectors.Also,inthisstudyionosphericsoundingdataob-tained during29thSeptemberto2ndOctober,2012atJicamarca(JIC),Peru,SãoLuis(SL),Fortaleza(FZ),Brazil, andPortStanley(PST),arepresented.Onthenightof30September?01October,inthemainandrecoveryphase,theh´F variationsshowedanunusualupliftingoftheFregionatequatorial(JIC,SLandFZ) andmid-(PST)latitudestationsrelatedwiththepropagationsoftravelingionosphericdisturbances(TIDs) generatedbyJouleheatingatauroralregions.On30September,theVTECvariationsandfoF2observationsatmid-latitudestations(Americansector)showedalong-durationpositiveionosphericstorm (over6hofenhancement)associatedwithlarge-scalewindcirculationsandequatorwardneutralwinds. Also,on01October,along-durationpositiveionosphericstormwasobservedatequatorial,low-and mid-latitudestationsintheAfricansector,relatedwiththelarge-scalewindcirculationsandequatorwardneutralwinds.On01and02October,positiveionosphericstormswereobservedatequatorial,low-andmid-latitudestationsintheAmericansector,possiblyassociatedwiththeTIDsandan equatorwardneutralwind.Also,on01Octobernegativeionosphericstormswereobservedatequatorial,low-andmid-latituderegionsintheAmericansector,probablyassociatedwiththechangesinthe O/N2 ratio. Onthenightof30September?01October,ionosphericplasmabubbleswereobservedatequatorial,low-andmid-latitudestationsintheSouthAmericansector,possiblyassociatedwiththeoccurrence ofgeomagneticstorm