Short-term variability of the equatorial ionosphere and its association with planetary-scale waves
Final Report Abstract
The primary goal of this project is to improve our understanding of the day-to-day variability, or “weather”, of the ionosphere, at altitudes of ca. 100−600 km. In particular, this project focuses on the ionospheric variability associated with globalscale atmospheric waves, such as planetary waves and atmospheric tides. Planetary waves have a period longer than a day and shorter than several weeks. Their ionospheric effects could make a contribution to the ionospheric day-to-day variability. We have found that there is often a “burst” of planetary-wave activity in the middle atmosphere (i.e., the neutral atmosphere just below the ionosphere, ca. 50−100 km) during sudden stratospheric warming (SSW) events. The “Fourier-wavelet” technique has been developed to enable to identify planetary-wave bursts during SSWs. We have also found evidence of the planetary-wave effect on the ionosphere during SSWs. In particular, during the Antarctic SSW event of September 2019, ionospheric oscillations with a period of ~6 days are detected in various parameters, including the equatorial electrojet, zonal electric field, and F- region plasma densities, along with a strong quasi-6-day wave in the middle atmosphere. Besides the quasi-6-day wave, the equatorial Kelvin wave with a period of ~3 days plays an important role for the ionospheric dayto-day variability at low latitudes. Atmospheric tides have a period of a solar day (24h) and its harmonics (12h, 8h, …). Thus, they do not make a direct contribution to the ionospheric day-to-day variability. Nevertheless, the interaction of tides with planetary waves can lead to “secondary waves”. For instance, the interaction between the semidiurnal tide (12h) and quasi-6- day wave results in a pair of global-scale waves; one with a period of 11h and the other with a period of 13h. These secondary waves were found to be important for the ionospheric day-to-day variability observed during the September 2019 SSW event. As briefly highlighted above, the ionosphere is subject to atmospheric forcing by various global-scale waves. This project was able to identify the importance of planetary waves and their interaction with tides for the ionospheric day-to-day variability.
Publications
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Ionospheric variability associated with the quasi-6-day planetary wave, JpGU 2019, Chiba, Japan.
Yamazaki, Y.
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Large‐Amplitude Quasi‐10‐Day Waves in the Middle Atmosphere During Final Warmings. Journal of Geophysical Research: Atmospheres, 124(17-18), 9874-9892.
Yamazaki, Y. & Matthias, V.
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Planetary wave effects on the ionosphere, at International Symposium on Physics 2020, online.
Yamazaki, Y.
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September 2019 Antarctic Sudden Stratospheric Warming: Quasi‐6‐Day Wave Burst and Ionospheric Effects. Geophysical Research Letters, 47(1).
Yamazaki, Y.; Matthias, V.; Miyoshi, Y.; Stolle, C.; Siddiqui, T.; Kervalishvili, G.; Laštovička, J.; Kozubek, M.; Ward, W.; Themens, D. R.; Kristoffersen, S. & Alken, P.
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Whole Atmosphere Model Simulations of Ultrafast Kelvin Wave Effects in the Ionosphere and Thermosphere. Journal of Geophysical Research: Space Physics, 125(7).
Yamazaki, Y.; Miyoshi, Y.; Xiong, C.; Stolle, C.; Soares, G. & Yoshikawa, A.
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Zonal Wave Number Diagnosis of Rossby Wave‐Like Oscillations Using Paired Ground‐Based Radars. Journal of Geophysical Research: Atmospheres, 125(12).
He, Maosheng; Yamazaki, Yosuke; Hoffmann, Peter; Hall, Chris M.; Tsutsumi, Masaki; Li, Guozhu & Chau, Jorge Luis
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Examining the Wind Shear Theory of Sporadic E With ICON/MIGHTI Winds and COSMIC‐2 Radio Occultation Data. Geophysical Research Letters, 49(1).
Yamazaki, Y.; Arras, C.; Andoh, S.; Miyoshi, Y.; Shinagawa, H.; Harding, B. J.; Englert, C. R.; Immel, T. J.; Sobhkhiz‐Miandehi, S. & Stolle, C.
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Ionospheric Signatures of Secondary Waves From Quasi‐6‐Day Wave and Tide Interactions. Journal of Geophysical Research: Space Physics, 126(4).
Yamazaki, Y. & Miyoshi, Y.
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Neutral Wind Profiles During Periods of Eastward and Westward Equatorial Electrojet. Geophysical Research Letters, 48(11).
Yamazaki, Y.; Harding, B. J.; Stolle, C. & Matzka, J.
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Quasi‐4‐Day Wave: Atmospheric Manifestation of the First Symmetric Rossby Normal Mode of Zonal Wavenumber 2. Journal of Geophysical Research: Atmospheres, 126(13).
Yamazaki, Y.; Matthias, V. & Miyoshi, Y.
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Whole atmosphere coupling by the quasi-6-day wave during the September 2019 Antarctic sudden stratospheric warming, 2021 Virtual CEDAR Workshop, Scientific Highlight (Plenary session).
Yamazaki, Y.
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Comparison of the tidal signatures in sporadic E and vertical ion convergence rate, using FORMOSAT-3/COSMIC radio occultation observations and GAIA model. Earth, Planets and Space, 74(1).
Sobhkhiz-Miandehi, Sahar; Yamazaki, Yosuke; Arras, Christina; Miyoshi, Yasunobu & Shinagawa, Hiroyuki
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Geomagnetic Detection of the Atmospheric Acoustic Resonance at 3.8 mHz During the Hunga Tonga Eruption Event on 15 January 2022. Journal of Geophysical Research: Space Physics, 127(7).
Yamazaki, Yosuke; Soares, Gabriel & Matzka, Jürgen
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Geomagnetic observations from ground and satellites for upper atmospheric studies, 15th Quadrennial Solar-Terrestrial Physics Symposium (STP-15), online.
Yamazaki, Y.
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Solar and lunar daily geomagnetic variations and their equivalent current systems observed by Swarm. Earth, Planets and Space, 74(1).
Yamazaki, Yosuke
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The importance of lower thermospheric winds for studies of the low-latitude ionosphere, Jicamarca 60th Anniversary Workshop, Lima, Peru.
Yamazaki, Y.
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Using Principal Component Analysis of Satellite and Ground Magnetic Data to Model the Equatorial Electrojet and Derive Its Tidal Composition. Journal of Geophysical Research: Space Physics, 127(9).
Soares, Gabriel; Yamazaki, Yosuke; Morschhauser, Achim; Matzka, Jürgen; Pinheiro, Katia J.; Stolle, Claudia; Alken, Patrick; Yoshikawa, Akimasa; Hozumi, Kornyanat; Kulkarni, Atul & Supnithi, Pornchai
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A comparison of sporadic E layer recorded by mid latitude ionosonde stations and conjunction radio occultation measurements, IUGG 2023, Berlin, Germany.
Sobhkhiz, S., Yamazaki, Y., Arras, C. & Themens, D. R.
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A method to derive Fourier–wavelet spectra for the characterization of global-scale waves in the mesosphere and lower thermosphere and its MATLAB and Python software (fourierwavelet v1.1). Geoscientific Model Development, 16(16), 4749-4766.
Yamazaki, Yosuke
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A study of ionospheric dynamo currents using Swarm geomagnetic field measurements, IUGG 2023, Berlin, Germany.
Yamazaki, Y.
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Lower thermopsheric winds from ICON/MIGHTI and their impact on the ionosphere, IUGG 2023, Berlin, Germany.
Yamazaki, Y.
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Lower thermospheric winds from ICON/MIGHTI and comparison with the UA-ICON model, JpGU 2023, Chiba, Japan.
Yamazaki, Y., Stolle, C., Kunze, M., Siddiqui & T. Harding, B. J.
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Lower thermospheric winds from ICON/MIGHTI and their impact on the ionosphere, ICTP- SCOSTEP-ISWI, Trieste, Italy.
Yamazaki, Y., Stolle, C., Harding, B. J. & Arras C.
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Monthly Climatologies of Zonal‐Mean and Tidal Winds in the Thermosphere as Observed by ICON/MIGHTI During April 2020–March 2022. Earth and Space Science, 10(6).
Yamazaki, Y.; Harding, B. J.; Qiu, L.; Stolle, C.; Siddiqui, T. A.; Miyoshi, Y.; Englert, C. R. & England, S. L.
