Occurrence of Ionospheric Equatorial Ionization Anomaly at 840 km Height Observed by the DMSP Satellites at Solar Maximum Dusk

Abstract Although it is accepted that the electron density double peaks of the Equatorial Ionization Anomaly (EIA) generally merge into a single‐peak with increasing altitude and thus the signature of EIA becomes inconspicuous in the higher topside ionosphere, it is still unclear that to what altitu...

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Main Authors: Jiacheng Li, Yiding Chen, Libo Liu, Huijun Le, Ruilong Zhang, He Huang, Wenbo Li
Format: Article
Language:English
Published: Wiley 2021-05-01
Series:Space Weather
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Online Access:https://doi.org/10.1029/2020SW002690
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author Jiacheng Li
Yiding Chen
Libo Liu
Huijun Le
Ruilong Zhang
He Huang
Wenbo Li
author_facet Jiacheng Li
Yiding Chen
Libo Liu
Huijun Le
Ruilong Zhang
He Huang
Wenbo Li
author_sort Jiacheng Li
collection DOAJ
description Abstract Although it is accepted that the electron density double peaks of the Equatorial Ionization Anomaly (EIA) generally merge into a single‐peak with increasing altitude and thus the signature of EIA becomes inconspicuous in the higher topside ionosphere, it is still unclear that to what altitudes the double‐peak structure can extend. In this study, we used measurements of the DMSP F12‐F15 satellites at ∼840 km altitude to examine EIA occurrence rate (EOR) in the dusk sector during solar maximum years 2000–2002 by checking latitudinal profiles of the ion density orbit by orbit. The EIA can still be observed at DMSP heights, and the EOR can reach 30% at specific longitudes at dusk side in equinox seasons. The EOR behaves wave‐like longitude structure that depends on seasons. Moreover, the irregularity occurrence rate shows similar longitudinal and seasonal variations with EOR, and the local time evolutions of them show that the former peaks earlier than the latter. The observations of equatorial vertical E × B plasma drifts indicated that the prereversal enhancement (PRE) of eastward electric field plays a significant role in the formation of the equatorial ionization anomaly at an altitude of 840 km just after sunset, but the occurrence of the equatorial ionization anomaly at this altitude dose not precisely represent the characteristics of the prereversal enhancement of eastward electric field.
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spelling doaj-art-c18e82166f054cf7aeb44613ea2d426b2025-01-14T16:31:31ZengWileySpace Weather1542-73902021-05-01195n/an/a10.1029/2020SW002690Occurrence of Ionospheric Equatorial Ionization Anomaly at 840 km Height Observed by the DMSP Satellites at Solar Maximum DuskJiacheng Li0Yiding Chen1Libo Liu2Huijun Le3Ruilong Zhang4He Huang5Wenbo Li6Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing ChinaKey Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing ChinaKey Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing ChinaKey Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing ChinaKey Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing ChinaKey Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing ChinaKey Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Beijing ChinaAbstract Although it is accepted that the electron density double peaks of the Equatorial Ionization Anomaly (EIA) generally merge into a single‐peak with increasing altitude and thus the signature of EIA becomes inconspicuous in the higher topside ionosphere, it is still unclear that to what altitudes the double‐peak structure can extend. In this study, we used measurements of the DMSP F12‐F15 satellites at ∼840 km altitude to examine EIA occurrence rate (EOR) in the dusk sector during solar maximum years 2000–2002 by checking latitudinal profiles of the ion density orbit by orbit. The EIA can still be observed at DMSP heights, and the EOR can reach 30% at specific longitudes at dusk side in equinox seasons. The EOR behaves wave‐like longitude structure that depends on seasons. Moreover, the irregularity occurrence rate shows similar longitudinal and seasonal variations with EOR, and the local time evolutions of them show that the former peaks earlier than the latter. The observations of equatorial vertical E × B plasma drifts indicated that the prereversal enhancement (PRE) of eastward electric field plays a significant role in the formation of the equatorial ionization anomaly at an altitude of 840 km just after sunset, but the occurrence of the equatorial ionization anomaly at this altitude dose not precisely represent the characteristics of the prereversal enhancement of eastward electric field.https://doi.org/10.1029/2020SW002690DMSPEIAirregularityplasma driftROCSAT‐1topside ionosphere
spellingShingle Jiacheng Li
Yiding Chen
Libo Liu
Huijun Le
Ruilong Zhang
He Huang
Wenbo Li
Occurrence of Ionospheric Equatorial Ionization Anomaly at 840 km Height Observed by the DMSP Satellites at Solar Maximum Dusk
Space Weather
DMSP
EIA
irregularity
plasma drift
ROCSAT‐1
topside ionosphere
title Occurrence of Ionospheric Equatorial Ionization Anomaly at 840 km Height Observed by the DMSP Satellites at Solar Maximum Dusk
title_full Occurrence of Ionospheric Equatorial Ionization Anomaly at 840 km Height Observed by the DMSP Satellites at Solar Maximum Dusk
title_fullStr Occurrence of Ionospheric Equatorial Ionization Anomaly at 840 km Height Observed by the DMSP Satellites at Solar Maximum Dusk
title_full_unstemmed Occurrence of Ionospheric Equatorial Ionization Anomaly at 840 km Height Observed by the DMSP Satellites at Solar Maximum Dusk
title_short Occurrence of Ionospheric Equatorial Ionization Anomaly at 840 km Height Observed by the DMSP Satellites at Solar Maximum Dusk
title_sort occurrence of ionospheric equatorial ionization anomaly at 840 km height observed by the dmsp satellites at solar maximum dusk
topic DMSP
EIA
irregularity
plasma drift
ROCSAT‐1
topside ionosphere
url https://doi.org/10.1029/2020SW002690
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