Gravity waves in the thermosphere simulated by a general circulation model

Yasunobu Miyoshi, Hitoshi Fujiwara

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

By using a general circulation model that contains the region from the ground surface to the upper thermosphere, characteristics of gravity waves in the mesosphere and thermosphere are examined. At 100 km height, the dominant periods of gravity waves for zonal wave number 20 (zonal wavelength λx ≈ 2000 km), 40(λx ≈ 1000 km) and 80 (λx ≈ 500 km) are 6 h, 3 h and 1.5-2 h, respectively. For the individual zonal wave numbers, the corresponding dominant period becomes shorter at higher altitudes due to dissipation processes in the thermosphere, such as molecular viscosity and ion drag force. This means that gravity waves with larger horizontal phase velocity (larger vertical wavelength) can penetrate into the lower thermosphere. The vertical energy flux due to gravity waves indicates that upward propagation from the lower atmosphere to the thermosphere is dominant. Fluctuations of the horizontal wind associated with gravity waves and its relation to the ionospheric variation are discussed. Short-period g ravity waves into the thermosphere induce day-to-day variations of the zonal wind in the upper thermosphere. This result suggests that day-to-day variability of the zonal wind caused by gravity waves is expected to contribute to the ionospheric variability.

Original languageEnglish
Article numberD01101
JournalJournal of Geophysical Research Atmospheres
Volume113
Issue number1
DOIs
Publication statusPublished - Jan 16 2008

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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