| Abstrakt: |
Equatorial longitudinal ionospheric variations are influenced by various physical processes, including the east–west directed electric field (equatorial electrojet, EEJ). However, the specific impact of EEJ variability on the total electron content (TEC) variations in different longitudinal sectors has not been thoroughly explored. Therefore, this study focuses on investigating the longitudinal changes in the EEJ and how they affect the daily patterns of the equatorial ionization anomaly (EIA) on geomagnetic calm time from 2011 to 2013. EEJ was estimated using pairs of magnetometer observations across eight sectors globally, while Global Positioning System (GPS) TEC data were collected from three stations at the southern/northern crests and trough locations within the longitudinal sector. The study presents seasonal variations in EIA TEC during different seasons alongside longitudinal variations of EEJ in both the southern/northern hemispheres. Statistical analysis reveals that the southern/northern equatorial ionospheric anomaly (EIA) crests exhibit positive correlations with the peaks of EEJ in all regions, indicating that the variations in EIA strength align with those of EEJ. The seasonal mean EEJ and EIA crests are most pronounced during equinox seasonal months over the Southeast Asian, Peruvian, and Philippine regions in the investigation period. In these regions, the correlation coefficients for the TEC near the northern crests are relatively higher than those for the southern crests, while the southern crest shows slightly higher values across the Pacific, Indian, Brazilian, and West African regions. Notably, the correlation between an integrated EEJ and the strength of EIA is stronger than that with the day maximum EEJ. The study also presents the seasonal characteristics of EEJ and EIA, with counter electrojets (CEJ) occurrences occurring more observable in Brazil and Africa. However, in most equinoctial seasons, the highest TEC peak close to the EIA crest is observed in these sectors. Research Highlights: The northern/southern TEC of EIA crests exhibit variations that correlate with the variations in EEJ. TEC of EIA strength variations align with those in EEJ during different seasons. The correlation coefficients between EIA and EEJ exhibit high values across all sectors during the moderate year of 2011. [ABSTRACT FROM AUTHOR] |
