Bibliography
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Solar cycle, seasonal, and dawn-to-dusk variations of the hydrogen in the upper thermosphere
Author | Wan, Changan; Qin, Jianqi; Paxton, Larry; |
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Abstract | Atomic hydrogen is one of the least-understood atmospheric constituents whose distribution is important for the studies of aeronomy and magnetospheric physics. Using 6 years of space-based daytime Lyman-α observations from 2002 to 2007, we quantify the solar cycle, seasonal, and dawn-to-dusk variations of the H density in the upper thermosphere. Our results show evident dawn-dusk asymmetry of the exobase H density that decreases nearly linearly from dawn to dusk. The observed asymmetry in terms of the dawn-dusk density ratio decreases with declining solar activity and is larger in summer than in other seasons. Such variations are not predicted by the NRLMSISE-00 model and the NRLMSIS 2.0 model. Those models predict the opposite solar cycle trend and little seasonal variation of the degree of asymmetry. |
Year of Publication | 2022 |
Journal | Journal of Geophysical Research: Space Physics |
Volume | |
Number of Pages | e2022JA030504 |
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Date Published | |
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URL | |
DOI | 10.1029/2022JA030504 |