Numerical Study of Traveling Ionospheric Disturbances Generated by an Upward Propagating Gravity Wave

Yasunobu Miyoshi, Hidekatsu Jin, Hitoshi Fujiwara, Hiroyuki Shinagawa

研究成果: Contribution to journalArticle査読

8 被引用数 (Scopus)

抄録

Using a global atmosphere-ionosphere coupled model, the characteristics and excitation source of traveling ionospheric disturbances (TIDs) during geomagnetically quiet periods are studied. This is the first paper concerning the simulation of TIDs generated by upward propagating gravity waves (GWs) that are spontaneously generated in the model. The dominant horizontal wavelengths of the simulated TIDs range from 700 to 1,500 km. The dominant periods and horizontal phase velocities of TIDs are 45–90 min and 250–300 m s−1, respectively. These features are the same as those of GWs in the 250–300 km height region. The phase of the electron density variations due to TIDs descends with increasing time, which is characteristic of the upward propagation of GWs. These electron density variations that are caused due to TIDs are explained by the transport processes of a neutral wind along a geomagnetic field line. These results indicate that the electron density variations respond locally to the passage of neutral wind fluctuations associated with upward propagating GWs. The GWs that excite TIDs are secondary GWs, which are generated in the mesosphere and lower thermosphere via the dissipation/breaking of tropospheric GWs. The magnitudes of TIDs at middle latitudes are larger in winter than in summer. The mechanisms of seasonal and day-to-day variations in TIDs that are caused due to GWs are discussed in this study.

本文言語英語
ページ(範囲)2141-2155
ページ数15
ジャーナルJournal of Geophysical Research: Space Physics
123
3
DOI
出版ステータス出版済み - 3 2018

All Science Journal Classification (ASJC) codes

  • 宇宙惑星科学
  • 地球物理学

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