Numerical simulation of the equatorial wind jet in the thermosphere

Yasunobu Miyoshi, Hitoshi Fujiwara, Hidekatsu Jin, Hiroyuki Shinagawa, Huixin Liu

研究成果: ジャーナルへの寄稿学術誌査読

24 被引用数 (Scopus)


We have examined excitation mechanism of the fast jet of the neutral atmosphere along the dip equator in the upper thermosphere. The zonal momentum balance of the neutral atmosphere is estimated using an atmosphere-ionosphere coupled model. The coupled model used in this study is a self-consistent global model of the atmosphere and ionosphere covering the height range from the ground surface to the exobase. It can reproduce the observed equatorial fast jet above 250km heights. The analysis of the zonal momentum balance reveals that the pressure gradient and ion drag play an important role on the formation of the fast jet near the dip equator. In particular, the fast jet near the equator is closely related with the latitudinal difference of the ion drag force. We also investigate the zonal momentum balance of the longitudinal wave-4 structure of the zonal wind in the fixed local time frame. Furthermore, significant day-to-day variations in the neutral zonal wind and the ion drift near the dip equator are obtained although the solar UV/EUV fluxes and the energy input from the magnetosphere are assumed to be constant during the numerical simulation. This result indicates the importance of the lower atmospheric variability on day-to-day variations in the thermosphere/ionosphere.

ジャーナルJournal of Geophysical Research: Space Physics
出版ステータス出版済み - 2012

!!!All Science Journal Classification (ASJC) codes

  • 宇宙惑星科学
  • 地球物理学


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