1. Contributions of Ionospheric Migrating Tides to Ionospheric Intra‐Annual Variations.
- Author
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Chen, Jinyuan, Ren, Xiaodong, Liu, Hang, Le, Xuan, Yang, Pengxi, Zhu, Wei, and Zhang, Xiaohong
- Subjects
TELECOMMUNICATION satellites ,GLOBAL Positioning System ,ATMOSPHERIC boundary layer ,ATMOSPHERE ,ATMOSPHERIC tides - Abstract
The Earth's ionosphere undergoes regular intra‐annual variations (IAVs) characterized by two peaks and troughs around the equinoxes and solstices. This phenomenon is crucial for analyzing the ionospheric response to geomagnetic storms. This study presents a comprehensive analysis of the IAVs contributed by diurnal and semidiurnal migrating tides (DW1 and SW2) using Global Ionospheric Maps (GIMs) data from 2017 to 2021. Through data stacking techniques, the seasonal variability and splitting phenomenon of DW1 and SW2 across different latitudes are examined. The findings indicate that the splitting of these tides can be attributed to their quasi‐periodic variations, predominantly composed of annual oscillation (AO) and semiannual oscillation (SAO). The combination of DW1, SW2, and their side‐band harmonics results in beats with annual and semiannual periodicities, enabling the restoration of the seasonal variations in DW1 and SW2. The ionospheric day‐to‐day variations were reconstructed by superimposing DW1 and SW2, and their IAVs were evaluated using the envelope method. Comparison with IAVs driven by Earth's orbital geometry reveals that tide‐driven IAVs are more significant, and both exhibit solar activity dependence. The results advance the understanding of ionospheric variability, emphasizing the critical role of tidal contributions. Plain Language Summary: The ionosphere, an essential layer of Earth's atmosphere, significantly impacts high‐frequency communication and global satellite navigation systems. It exhibits seasonal variations, characterized by peaks during equinoxes and troughs around solstices. While the underlying physics of these variations still requires further exploration, this study uses global ionosphere maps from 2017 to 2021 to investigate the intra‐annual variations (IAVs) attributed to ionospheric migrating tides. Our findings reveal the "splitting" behavior of DW1 and SW2, where these waves separate into multiple frequency components due to their quasi‐periodic nature. This splitting phenomenon primarily arises from the annual and semiannual variations in the amplitudes of DW1 and SW2, enabling the reconstruction of ionospheric day‐to‐day variations. Interestingly, the IAVs driven by the migrating tides have a more significant impact on seasonal changes than the direct effects of Earth's orbit. The atmospheric tides in the lower atmosphere may influence the composition of the upper atmosphere, subsequently affecting the ionosphere. Overall, this research highlights the intricate interplay of mechanisms shaping the seasonal patterns of the ionosphere. Key Points: Under high‐frequency resolution spectra, the ionospheric diurnal and semidiurnal migrating tides will splitIonospheric intra‐annual variations (IAVs) can be reconstructed by combining migrating tides and their side‐band harmonicsThe IAVs in the ionospheric day‐to‐day variations are more significant than those induced by the geometry of Earth's orbit [ABSTRACT FROM AUTHOR]
- Published
- 2024
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