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Abstract
In this study, we evaluate the El Niño–Southern Oscillation (ENSO) signals in the two dominant temperature diurnal tides, diurnal westward wavenumber 1 (DW1) and diurnal eastward wavenumber 3 (DE3) on the quasi-biennial oscillation (QBO) scale (18–34 months) from 50 to 100 km altitudes. The tides are derived from the 21-year (January 1996–February 2017) Ground-to-Topside model of Atmosphere and Ionosphere for Aeronomy (GAIA) temperature simulations and 15-year (February 2002–February 2017) Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED)/Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperature observations. The results show that ENSO warm phases shorten the period (~ 2 years) of the QBO in DW1 amplitude near the equator and DE3 amplitude at low latitudes of the Northern Hemisphere. In contrast, the QBO period lengthens (~ 2.5 years) during the ENSO neutral and cold phases. Correlation analysis shows the long-lasting effect of ENSO on the tidal QBO in the mesosphere and lower thermosphere.
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1 Department of Earth and Planetary Science, Kyushu University, Fukuoka, Japan
2 Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China; Geoscience School, University of the Chinese Academy of Sciences, Beijing, China
3 Graduate Institute of Space Science, National Central University, Taoyuan, Taiwan; Center for Astronautical Physics and Engineering, National Central University, Taoyuan, Taiwan