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Observation of Postsunset OI 135.6 nm Radiance Enhancement Over South America by the GOLD Mission
Author(s) -
Cai Xuguang,
Burns Alan G.,
Wang Wenbin,
Qian Liying,
Liu Jing,
Solomon Stanley C.,
Eastes Richard W.,
Daniell Robert E.,
Martinis Carlos R.,
McClintock William E.,
Batista Inez S.
Publication year - 2021
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2020ja028108
Subject(s) - radiance , crest , geology , tec , geodesy , ionosphere , depth sounding , remote sensing , physics , optics , geophysics , oceanography
The Global‐scale Observation of Limb and Disk (GOLD) mission, for the first time, provides synoptic two‐dimensional (2D) maps of OI 135.6 nm observations. These maps describe the unambiguous and dynamic evolution of nighttime ionospheric F 2 ‐peak electron densities ( N m F 2 ) as the 135.6 nm airglow emission radiance correlates well with N m F 2 at night. On November 19, 2018, the 135.6 nm radiance measured by GOLD, N m F 2 measured by a digisonde, and GPS total electron content (TEC) measurements at Cachoeira Paulista (CP) all showed a postsunset enhancement, with an increase near 22:30 universal time. The 135.6 nm radiance map showed that this enhancement was due to the southward movement of the southern equatorial ionization anomaly (EIA) crest. Therefore, the GOLD observation showed the linkage between postsunset enhancement of N m F 2 and EIA movement. Furthermore, unlike the southward movement of the southern crest, the corresponding EIA northern crest, however, did not show northward motion. This is the first time that the EIA hemispheric asymmetry, which included both different densities and movement of two crests in a short time period (<2‐h), was captured. The cause of this asymmetric movement of the two crests is not clear and requires further investigation.