Rights statement: Accepted for publication in Journal of Geophysical Research: Space Physics. Copyright 2017 American Geophysical Union. Further reproduction or electronic distribution is not permitted.
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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Quasi-biennial oscillation of the ionospheric wind dynamo
AU - Yamazaki, Yosuke
AU - Liu, Huixin
AU - Sun, Yang-Yi
AU - Miyoshi, Yasunobu
AU - Kosch, Michael Jurgen
AU - Mlynczak, Martin
N1 - Accepted for publication in Journal of Geophysical Research: Space Physics. Copyright 2017 American Geophysical Union. Further reproduction or electronic distribution is not permitted.
PY - 2017/3
Y1 - 2017/3
N2 - The interannual variation of the ionospheric solar quiet (Sq) current system is examined. A dense magnetometer network over Japan enables the accurate determination of the central position of the northern Sq current loop or the Sq current focus, during 1999–2015. It is found that the Sq focus latitude undergoes an interannual variation of ±2° with a period of approximately 28 months, similar to the quasi-biennial oscillation (QBO) in the tropical lower stratosphere. The QBO-like variation of Sq is particularly evident during 2005–2013. No corresponding interannual variability is found in solar extreme ultraviolet radiation. Comparisons with tidal winds, derived from a whole-atmosphere model, reveal that the QBO-like variation of the Sq current focus is highly correlated with the amplitude variations of migrating and nonmigrating diurnal tides in the lower thermosphere. The results suggest that the stratospheric QBO can influence the ionospheric wind dynamo through the QBO modulation of tides.
AB - The interannual variation of the ionospheric solar quiet (Sq) current system is examined. A dense magnetometer network over Japan enables the accurate determination of the central position of the northern Sq current loop or the Sq current focus, during 1999–2015. It is found that the Sq focus latitude undergoes an interannual variation of ±2° with a period of approximately 28 months, similar to the quasi-biennial oscillation (QBO) in the tropical lower stratosphere. The QBO-like variation of Sq is particularly evident during 2005–2013. No corresponding interannual variability is found in solar extreme ultraviolet radiation. Comparisons with tidal winds, derived from a whole-atmosphere model, reveal that the QBO-like variation of the Sq current focus is highly correlated with the amplitude variations of migrating and nonmigrating diurnal tides in the lower thermosphere. The results suggest that the stratospheric QBO can influence the ionospheric wind dynamo through the QBO modulation of tides.
KW - QBO
KW - geomagnetic daily variation
KW - Sq current system
KW - interannual variability
KW - atmospheric tides
KW - GAIA model
U2 - 10.1002/2016JA023684
DO - 10.1002/2016JA023684
M3 - Journal article
VL - 122
SP - 3553
EP - 3569
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
SN - 2169-9402
IS - 3
ER -