University of Tehran Press Journal of the Earth and Space Physics 2538-371X 48 4 2023 02 20 The Effect of Variations of EEJ on the Ionospheric TEC at Different Longitudinal Sectors using Ground-based Observation The Effect of Variations of EEJ on the Ionospheric TEC at Different Longitudinal Sectors using Ground-based Observation 197 220 90869 10.22059/jesphys.2023.350185.1007464 FA Alemayehu Mengesha Cherkos Corresponding Author, Department of Physics, CNCS, Institute of Geophysics Space Science and Astronomy, Addis Ababa University, Addis Ababa, Ethiopia. E-mail: alexye9@yahoo.com 0000-0002-1809-9059 Melessew Nigussie Department of Physics, Washera Geospace and Radar Science Research Laboratory, Bahir Dar University, Bahir Dar, Ethiopia. E-mail: melessewnigussie@yahoo.com 0000-0001-7827-5117 Journal Article 2022 11 14 In this work, the longitudinal variations of equatorial electrojet (EEJ) and its effect on the diurnal behavior of the EIA during quiet days in the period of 2011- 2012 were investigated. EEJ has been estimated using a pair of ground-based magnetometers data from six longitudinal sectors, and the Global Positioning System (GPS) TEC have also been obtained at each longitudinal sector from three stations at Northern and Southern crests and trough regions. The statistical results show that the monthly mean variations of EIA crest are consistent with that of the strength of equatorial electrojet in most regions of the investigation. The mean EEJ and EIA crests are strongest around equinoctial months in the Peruvian and Southeast Asian sectors followed by the West African regions throughout the years investigated. The weakest EEJ peaks and TEC of EIA are observed over the Pacific sectors throughout the periods of investigation. The monthly mean characteristics of EEJ/counter electrojets (CEJ) and EIA are also presented. The results also show that the CEJ events occur more frequently in the Brazilian sectors followed by in the Peruvian and West African sectors. However, in most of the equinoctial months, the strongest equatorial EIA trough and weakest of EIA crests are observed in the Brazilian sector. The temporal extent of the well-developed EIA crest and its properties show a substantial dependence on the diurnal characteristics of the EEJ for each specific day. In this work, the longitudinal variations of equatorial electrojet (EEJ) and its effect on the diurnal behavior of the EIA during quiet days in the period of 2011- 2012 were investigated. EEJ has been estimated using a pair of ground-based magnetometers data from six longitudinal sectors, and the Global Positioning System (GPS) TEC have also been obtained at each longitudinal sector from three stations at Northern and Southern crests and trough regions. The statistical results show that the monthly mean variations of EIA crest are consistent with that of the strength of equatorial electrojet in most regions of the investigation. The mean EEJ and EIA crests are strongest around equinoctial months in the Peruvian and Southeast Asian sectors followed by the West African regions throughout the years investigated. The weakest EEJ peaks and TEC of EIA are observed over the Pacific sectors throughout the periods of investigation. The monthly mean characteristics of EEJ/counter electrojets (CEJ) and EIA are also presented. The results also show that the CEJ events occur more frequently in the Brazilian sectors followed by in the Peruvian and West African sectors. However, in most of the equinoctial months, the strongest equatorial EIA trough and weakest of EIA crests are observed in the Brazilian sector. The temporal extent of the well-developed EIA crest and its properties show a substantial dependence on the diurnal characteristics of the EEJ for each specific day. https://jesphys.ut.ac.ir/article_90869_101b206b08d40872e75bd29e0392c46c.pdf