Publication Date:
2019
Description:
Abstract
The up‐looking total electron contents (TECs) from the GRACE, SWARM‐A, TerraSAR‐X and MetOp‐A satellites and in situ electron density (Ne) from SWARM‐A were utilized to investigate the topside ionospheric conditions during the 7‐8 September 2017 geomagnetic storm. The rate of TEC index (ROTI) and rate of density index (RODI), which are derivative indices of TEC and Ne respectively, were also used to characterize the topside ionospheric irregularities. The main results of this study are as follows: (1) There were significant enhancements seen in the up‐looking TEC during the first main phase of the storm. (2) The up‐looking TEC didn’t show similar unusual enhancement as observed by ground‐based TEC in the Asian‐Australian sector during the recovery phase of the storm on 11th September. (3) Prominent TEC hemispheric asymmetry at the middle and high latitudes was observed at both day and night sectors. (4) Long‐duration recovery of topside TEC with respect to the pre‐storm condition was also detected in this event. (5) Nighttime ROTI enhancements were presented in a wide latitudinal range from the equator to the poles during the main phases of the storm. (6) The ionospheric electric field disturbances associated with IMF‐Bz fluctuations probably played a very important role in triggering ionospheric irregularities during the relatively weak geomagnetic activity on 7th September, which implies that ionospheric irregularities do not necessarily occur under the severe geomagnetic conditions only.
Print ISSN:
2169-9380
Electronic ISSN:
2169-9402
Topics:
Geosciences
,
Physics
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