Total electron content disturbances during minor sudden stratospheric warming, over the Brazilian region: A case study during January 2012

The effects of sudden stratospheric warming (SSW) on ionosphere have been investigated by several scientists, using different observational techniques and model simulations. However, the minor SSW event during January 2012 is one of those that are less studied. Influences of several types of possible drivers—minor SSW event, changing solar flux, moderate geomagnetic storm on 22–25 January, and one of the largest solar proton events on 23–30 January—make it a challenging period to interpret. In the present study, the GPS‐total electron content (TEC) measurements from a network of 72 receivers over the Brazilian region are considered. This network of 72 GPS‐TEC locations lies between 5°N and 30°S (35°) latitudes and 35°W and 65°W (30°) longitudes. Further, two chains of GPS receivers are used to study the response of the equatorial ionization anomaly (EIA) in the Brazilian eastern and western sectors, as well as its day‐to‐day variability before and during the SSW‐2012. It was noted that the TEC is depleted to the order of 30% all over the Brazilian region, from equator to beyond the EIA regions and from east to west sectors. It is also noticed that the EIA strengths at the east and west sectors were weakened during the SSW‐2012. However, the Brazilian eastern sector was found to be more disturbed compared to the western sector during this SSW‐2012 event. Key Points Disturbances during minor sudden stratospheric warming (SSW) A network of 72 GPS‐TEC locations lies between 5°N and 30°S The TEC in the Brazilian eastern sector was found to be more disturbed compared to the western sector during this SSW‐2012 event