A global view of gravity waves in the thermosphere simulated by a general circulation model

Yasunobu Miyoshi, Hitoshi Fujiwara, Hidekatsu Jin, Hiroyuki Shinagawa

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

In order to study the dynamical role of gravity waves (GWs) propagating upward from the lower atmosphere to the thermosphere, numerical simulation using a high-resolution general circulation model that contains the region from the ground surface to the exobase (about 500 km height) has been performed. Our results indicate that the zonal momentum drag due to breaking/dissipation of GWs (GW drag) plays an important role not only in the mesosphere but also in the thermosphere. In particular, the GW drag at high latitudes in the150-250 km height region exceeds 200 ms-1 (d)-1 and is important for the zonal momentum balance. The semidiurnal variation of the GW drag is dominant in the 100-200 km height region, while the diurnal variation of the GW drag prevails above a height of 200 km. The GW drag in the thermosphere is mainly directed against the background zonal wind, indicating the filtering effect by the background wind. A global view of the GW activity in the middle and upper atmosphere is also investigated. The global distribution of the GW activity in the thermosphere is not uniform, and there are some enhanced regions of the GW activity. The GW activity in the thermosphere is stronger in high latitudes than in low latitudes. The GW activity in the winter thermosphere is influenced by the mesospheric jet and the planetary wave activity in the mesosphere.

Original languageEnglish
Pages (from-to)5807-5820
Number of pages14
JournalJournal of Geophysical Research: Space Physics
Volume119
Issue number7
DOIs
Publication statusPublished - Jan 1 2014

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Oceanography
  • Forestry
  • Ecology
  • Aquatic Science
  • 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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