We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Observation of Postsunset OI 135.6 nm Radiance Enhancement Over South America by the GOLD Mission.
- Authors
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.
- Abstract
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 F2‐peak electron densities (NmF2) as the 135.6 nm airglow emission radiance correlates well with NmF2 at night. On November 19, 2018, the 135.6 nm radiance measured by GOLD, NmF2 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 NmF2 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.Plain Language Summary: The postsunset enhancement of equatorial ionospheric NmF2 has been observed by low Earth orbit satellites and ground‐based equipment. However, these observations can only provide variations along satellite orbits or at a single location. In this paper, we provide, for the first time, two‐dimensional (2D) maps of nighttime OI 135.6 nm airglow observations by GOLD. These maps describe unambiguous and dynamic evolution of nighttime NmF2 as the 135.6 nm radiance is correlated well with nighttime NmF2. On the night of November 19, 2018, GOLD observed 135.6 nm radiance, NmF2 measured by digisonde, and total electron content at Cachoeira Paulista (CP) all exhibited a postsunset enhancement. This is the first time that the two dimensional (2D) measurements of the ionosphere by a geostationary satellite are compared with local observations in the same time range. The evolution of 135.6 nm radiance map suggests that this enhancement was mainly due to the southward movement of the southern equatorial ionization anomaly (EIA) crest. The corresponding northern EIA crest of CP is over the Ocean, which can be observed by GOLD and found to keep stationary, but not easily by other means of observations. This asymmetric movement of the two EIA crests is unknown and requires further investigation in the future.Key Points: The GOLD nighttime observations match well with digisonde and total electron content at both single location and large areaThe observed postsunset OI 135.6 nm radiance enhancement at Cachoeira Paulista is due to the southward motion of southern Equatorial ionization anomaly (EIA) crestAn event of EIA asymmetry motion occurred during the same time period (<2 h)
- Publication
Journal of Geophysical Research. Space Physics, 2021, Vol 126, Issue 1, p1
- ISSN
2169-9380
- Publication type
Article
- DOI
10.1029/2020JA028108