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- Title
The UT Variation of the Polar Ionosphere Based on COSMIC Observations.
- Authors
Wu, Ye‐Wen; Liu, Rui‐Yuan; Zhang, Bei‐Chen; Wang, Wen‐Bin; Zhang, Shun‐Rong; Zhang, Qing‐He; Hu, Hong‐Qiao; Lu, Jian‐Yong
- Abstract
Mean polar electron content (mPEC) is used to analyze the polar ionosphere in both the Antarctic and Arctic. The mPEC is calculated over the polar region covering geographic latitudes higher than 60° from the global distributed vertical total electron contents based on electron density profiles observed by Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC). Using this parameter, the universal time (UT) variation of the polar ionosphere is quantitatively characterized. This UT variation exists an opposite phase (i.e., a 12‐hr phase difference) between them. The mPEC standard deviation (SD) in the Antarctic is larger in summer and autumn (being 1.37 and 0.78 TECu, respectively) and smaller in winter (0.29 TECu) and spring (0.61 TECu). The SD in the Arctic, however, is the largest in winter (0.14 TECu). In other seasons, the SD is less than 0.1 TECu. (being 0.07 TECu in spring, 0.05 TECu in summer, and 0.08 TECu in autumn, respectively). We use SD over the mean value to describe relative intensity of mPEC variations. This relative intensity is larger in winter for both Antarctic and Arctic regions. The UT variation in intensity is much stronger in the Antarctic than in the Arctic. These characteristics are attributed to the fact that the separation of the geomagnetic pole and geographic pole is dihedral and the angle is larger in the Antarctic. The larger angle causes more electrons transported into the polar region when the geomagnetic pole is on the dayside and fewer electrons transported into the polar region when the geomagnetic pole is on the nightside. Key Points: A mean polar electron content is proposed to characterize the polar ionosphere and in particular its universal time variationThe convection pattern is a main driver of the universal time variation of polar ionosphereThe universal time variation is stronger in the Antarctic because of the larger displacement between the geomagnetic and geographic poles
- Subjects
ELECTRONS; ELECTRON density; POLAR ionosphere; ELECTRON transport; STANDARD deviations
- Publication
Journal of Geophysical Research. Space Physics, 2019, Vol 124, Issue 4, p3139
- ISSN
2169-9380
- Publication type
Article
- DOI
10.1029/2018JA026106