Day-to-day Variability of the Equatorial Ionization Anomaly (EIA) over the Brazilian Sector Using GNSS-TEC Network During the Descending Phase of the Solar Cycle 24
Abstract
It has been noticed recently that the EIA in the Brazilian eastern, middle, and western sectors present significant longitudinal variability within a short separation due to the presence of typical magnetic field structure over South America (Dias et al., 2019). Therefore, the main motivation of this study is to investigate day-to-day characteristics of the equatorial ionization anomaly (EIA) in 3 different closely spaced longitudinal sectors over the Brazilian region, where the geomagnetic equator presents the largest declination. For this study, the observations from 3 latitudinal networks with 35 GNSS-VTEC stations spanning from the equator to low-latitudes are analyzed. The longitudinal variations of the EIA during the year 2016 in the descending phase of the solar activity is investigated. It is observed in this study that the EIA shows its classical behavior with a trough around the magnetic equator and crests at low-latitudes (from ±15o to ±20o) during the months of summer and spring. The number of cases within one year having well-developed EIA in the west, middle and east sectors are 233 (63.7%), 224 (61.2%), and 243 (66.4%), respectively. The absence of EIA is also found often during the months of winter and the number of such cases in the west, middle, and east are 82 (22.4%), 97 (26.5%), and 63 (17.2%), respectively. In addition, some special cases will be presented and studied with double crest peaks having the number of cases in the west, middle, and east sectors are 51 (13.9%), 45 (12.3%), and 60, (16.4%), respectively.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSA51B3142F
- Keywords:
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- 2415 Equatorial ionosphere;
- IONOSPHERE;
- 2431 Ionosphere/magnetosphere interactions;
- IONOSPHERE;
- 6969 Remote sensing;
- RADIO SCIENCE;
- 7944 Ionospheric effects on radio waves;
- SPACE WEATHER