Observed effects in the equatorial and low-latitude ionosphere in the South American and African sectors during the 2012 minor sudden stratospheric warming

摘要

Abstract In this paper, the effects of a minor sudden stratospheric warming (SSW) event of 2012 in the ionosphere over South American and African sectors have been studied using C/NOFS satellite data and GPS observations. Also, the magnetometer measurements obtained at two stations in the equatorial and low-latitude regions in the South American sector are presented. There were significant Vertical Total Electron Content (VTEC) depletions in the afternoon in both South American and African sectors during the 2012 minor SSW event. A novel feature of the present study is the reduction of the quasi 16-day oscillation (periods ranging from 11 to 20 days) in the daily averaged VTEC in the Brazilian and African sector during an SSW event. Also, the results for the Brazilian sector show an amplification of the ~2–6day period in the daily averaged VTEC at equatorial and low-latitude regions, after the SSW temperature peak. This investigation shows that a minor SSW can affect the irregularities at ionospheric heights in the Brazilian and African sectors. Ground-based magnetometer measurements in the American sector shows strongly enhanced equatorial electrojet (EEJ) after the SSW temperature peak. Highlights