Excitation mechanism of non-migrating tides

Yasunobu Miyoshi, Dora Pancheva, Plamen Mukhtarov, Hidekatsu Jin, Hitoshi Fujiwara, Hiroyuki Shinagawa

研究成果: Contribution to journalArticle査読

13 被引用数 (Scopus)

抄録

Using an atmosphere-ionosphere coupled model, the excitation source and temporal (seasonal and interannual) variations in non-migrating tides are investigated in this study. We first focus our attention on temporal variations in eastward moving diurnal tide with zonal wavenumber 3 (DE3), which is the largest of all the non-migrating tides in the mesosphere and lower thermosphere (MLT). Our simulation results indicate that upward propagation of the DE3 excited in the troposphere is sensitive to the zonal mean zonal wind in the stratosphere and mesosphere. The DE3 amplitude is enhanced in the region where the vertical shear of the zonal mean zonal wind is positive (westerly shear). Quasi-2-year variation in the DE3 amplitude in the MLT region is generated by quasi-2-year variation in the zonal mean zonal wind between 40 and 70 km, which is modulated by the stratospheric QBO. The excitation mechanisms of SW3 (westward moving semidiurnal tide with zonal wavenumber 3) and SW1 (westward moving semidiurnal tide with zonal wavenumber 1) are also investigated. During equinoxes, the SW3 and SW1 are excited by tropospheric heating (latent heat release and solar radiative heating) associated with cumulus convection in the tropics, and propagate upward into the MLT region. On the other hand, during solstices, SW3 and SW1 are generated in the winter stratosphere and mesosphere through the nonlinear interaction between the stationary planetary wave and migrating semidiurnal tide, and propagate upward to the lower thermosphere. The excitation sources of other non-migrating tides are also discussed.

本文言語英語
ページ(範囲)24-36
ページ数13
ジャーナルJournal of Atmospheric and Solar-Terrestrial Physics
156
DOI
出版ステータス出版済み - 4 1 2017

All Science Journal Classification (ASJC) codes

  • 地球物理学
  • 大気科学
  • 宇宙惑星科学

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