Strong longitudinal difference in ionospheric responses over Fortaleza (Brazil) and Jicamarca (Peru) during the January 2005 magnetic storm, dominated by northward IMF

Abstract

[1] In this study we investigate the response of the equatorial F layer to disturbance zonal electric field associated with IMF (interplanetary magnetic field) variations dominated by a strong northward Bz episode during the magnetic storm that occurred on 21 January, 2005. We compared the results obtained from Digisondes operated at Fortaleza, Brazil (Geogr. 3.9 S, 38.45 W; dip angle: À11.7 ) and Jicamarca, Peru (Geogr. 12.0 S, 76.8 W; dip angle: 0.64 ). A large auroral activity (AE) intensification that occurred at $1715 UT produced a large F-layer peak height increase (from 300 km to 600 km) over Jicamarca with no noticeable simultaneous effect over Fortaleza. Then the Bz turning northward at $1940 UT with a rapid change in AE that was accompanied by a large decrease of F layer height and total suppression of the PRE over Fortaleza with no simultaneous effect over Jicamarca. Strong increase in the AE index (from $400 to 1000 nT) with superimposed oscillations, under Bz North, that soon followed was associated with increases in both the F layer height and the vertical drift velocity over Fortaleza (at 2130 UT), with no corresponding signatures over Jicamarca. These remarkable contrasting responses to prompt penetration electric field (PPEF) as well as to disturbance wind dynamo electric field (DDEF) and other effects observed at the two locations separated only by 2 h in LT in the South American sector are presented and discussed in this paper. Effects on spread-F development and foF2 behavior during this storm event are also addressed in this work.

Positive and negative GPS‐TEC ionospheric storm effects during the extreme space weather event of March 2015 over the Brazilian sector

“…In addition, the F layer at Fortaleza descends during the main phase (19:40 UT/16:40 LT on 21 January), but this feature was not observed at Jicamarca. The longitudinal differences found by Santos et al [2012] are interesting, but we do expected some difference when we compare ionospheric data from equatorial region (Jicamarca) and low latitude (Fortaleza) during geomagnetic quiet and disturbed periods. On the other hand, the present investigation very clearly shows the EIA east-west differences using two chains of 10 GPS stations, each (from equator to beyond EIA crest).…”

Disturbance zonal and vertical plasma drifts in the Peruvian sector during solar minimum phases

“…Many studies have investigated the influence of these disturbance electric fields on the vertical drift and related phenomena of the equatorial ionosphere, including the equatorial ionization anomaly (EIA), plasma structuring leading to bubble irregularities, equatorial electrojet current system, etc. [e.g., Mannucci et al , ; Abdu et al , , , , ; Batista et al , , ; Kikuchi et al , ; Santos et al , ; Sastri et al , ; Sobral et al , , ; Tsurutani et al , ]. The effect of storm time penetration zonal electric field to produce large vertical plasma drift, or superfountain, and dayside total electron content enhancement with resulting EIA intensification was reported by Mannucci et al [] and Tsurutani et al [].…”

Storm‐induced plasma stream in the low‐latitude to midlatitude ionosphere

“…The same pattern was analyzed using a large data set obtained from TOPEX TEC measurements, and it was found to exist not only during magnetically quiet periods but also during disturbed periods when there were other disturbance sources for zonal electric fields [ Scherliess et al , ]. Santos et al [] reported a large longitudinal difference in zonal disturbance electric fields during a magnetic storm between Fortaleza, Brazil, and Jicamarca, Peru, which were separated by 30° longitude or 2 h in local time.…”