{"title":"地磁平静期（2011-2013 年）赤道电喷的纵向变化及其对赤道电离异常特征的影响","authors":"Alemayehu Mengesha Cherkos, Melessew Nigussie","doi":"10.1007/s12040-024-02383-3","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>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.</p><h3 data-test=\"abstract-sub-heading\">Research Highlights</h3><ul>\n<li>\n<p>The northern/southern TEC of EIA crests exhibit variations that correlate with the variations in EEJ.</p>\n</li>\n<li>\n<p>TEC of EIA strength variations align with those in EEJ during different seasons.</p>\n</li>\n<li>\n<p>The correlation coefficients between EIA and EEJ exhibit high values across all sectors during the moderate year of 2011.</p>\n</li>\n</ul>","PeriodicalId":15609,"journal":{"name":"Journal of Earth System Science","volume":null,"pages":null},"PeriodicalIF":1.3000,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Longitudinal variations in equatorial electrojet and its influence on equatorial ionization anomaly characteristics during geomagnetic calm time (2011–2013)\",\"authors\":\"Alemayehu Mengesha Cherkos, Melessew Nigussie\",\"doi\":\"10.1007/s12040-024-02383-3\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<h3 data-test=\\\"abstract-sub-heading\\\">Abstract</h3><p>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.</p><h3 data-test=\\\"abstract-sub-heading\\\">Research Highlights</h3><ul>\\n<li>\\n<p>The northern/southern TEC of EIA crests exhibit variations that correlate with the variations in EEJ.</p>\\n</li>\\n<li>\\n<p>TEC of EIA strength variations align with those in EEJ during different seasons.</p>\\n</li>\\n<li>\\n<p>The correlation coefficients between EIA and EEJ exhibit high values across all sectors during the moderate year of 2011.</p>\\n</li>\\n</ul>\",\"PeriodicalId\":15609,\"journal\":{\"name\":\"Journal of Earth System Science\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.3000,\"publicationDate\":\"2024-08-31\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Earth System Science\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1007/s12040-024-02383-3\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Earth System Science","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1007/s12040-024-02383-3","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
Longitudinal variations in equatorial electrojet and its influence on equatorial ionization anomaly characteristics during geomagnetic calm time (2011–2013)
Abstract
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.
期刊介绍：
The Journal of Earth System Science, an International Journal, was earlier a part of the Proceedings of the Indian Academy of Sciences – Section A begun in 1934, and later split in 1978 into theme journals. This journal was published as Proceedings – Earth and Planetary Sciences since 1978, and in 2005 was renamed ‘Journal of Earth System Science’.
The journal is highly inter-disciplinary and publishes scholarly research – new data, ideas, and conceptual advances – in Earth System Science. The focus is on the evolution of the Earth as a system: manuscripts describing changes of anthropogenic origin in a limited region are not considered unless they go beyond describing the changes to include an analysis of earth-system processes. The journal''s scope includes the solid earth (geosphere), the atmosphere, the hydrosphere (including cryosphere), and the biosphere; it also addresses related aspects of planetary and space sciences. Contributions pertaining to the Indian sub- continent and the surrounding Indian-Ocean region are particularly welcome. Given that a large number of manuscripts report either observations or model results for a limited domain, manuscripts intended for publication in JESS are expected to fulfill at least one of the following three criteria.
The data should be of relevance and should be of statistically significant size and from a region from where such data are sparse. If the data are from a well-sampled region, the data size should be considerable and advance our knowledge of the region.
A model study is carried out to explain observations reported either in the same manuscript or in the literature.
The analysis, whether of data or with models, is novel and the inferences advance the current knowledge.
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