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Research on thermospheric vertical wind using computer modeling

Research Project

Project/Area Number 10640428
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Space and upper atmospheric physics
Research InstitutionNagoya University

Principal Investigator

SHINAGAWA Hiroyuki  Nagoya University, Solar-Terrestrial Environment Laboratory, 太陽地球環境研究所, 助教授 (00262915)

Project Period (FY) 1998 – 1999
Project Status Completed (Fiscal Year 1999)
Budget Amount *help
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1999: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1998: ¥900,000 (Direct Cost: ¥900,000)
KeywordsUpper Atmosphere / Model / Dynamics / Aurora / Heating / Vertical Wind / Thermosphere / Ionosphere / 極域
Research Abstract

Two- and Three- dimensional nonhydrostatic thermospheric models have been developed in order to study behavior of vertical wind in the thermosphere. The calculated results were compared with the observations of thermospheric wind obtained by the Fabry-Perol interferometers. When large thermospheric vertical wind is observed in the vicinity of an auroral arc, oscillatory motion of the vertical wind occasionally occurs. This kind of variation could be explained by variations driven by local Joule heating. On the other hand, the vertical wind often exhibits very complicated behavior, suggesting that the thermospheric dynamics is controlled by combination of several processes such as (1) temporal and spatial variations of heat sources, (2) propagation of large-scale gravity waves generated in other regions, (3) effects of background wind of the thermosphere, and (4) interaction between gravity waves. In previous modeling of thermospheric and ionospheric dynamics associated with auroral arcs, the auroral arcs are assumed to be fixed in space. In reality, however, most of auroral arcs move very rapidly, indicating the heating regions also move rapidly. We studied the thermospheric and ionospheric dynamics including moving auroral arcs using the nonhydrostatic thermosphere-ionosphere model. By comparing the model results with EISCAT data, we obtained the following results, (1) when an auroral arc passes above the EISCAT radar site, field-aligned ion motion with a period of 15-40 min. and an amplitude of 10 - 30 m/s are often observed by EISCAT ; (2) our numerical model shows that field-aligned ion motion with a period of 15 min. are generated associated with moving an auroral arc ; (3) the model also predicts that a gravity wave with a period of 30 - 40 min. is generated when sudden heating occurs ; (4) the model tends to give smaller filed-aligned ion velocities than the observed ion velocities.

Report

(3 results)
  • 1999 Annual Research Report   Final Research Report Summary
  • 1998 Annual Research Report
  • Research Products

    (4 results)

All Other

All Publications (4 results)

  • [Publications] M. Ishii: "Dynamics of neutral wind in the polar region observed with two Fabry-Perot Interferometers"Earth, Planets and Space. 51巻・8号. 833-844 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M. Ishii, S. Oyama, S. Nozawa, R. Fujii, E. Sagawa S. Watari, and H. Shinagawa: "Dynamics of neutral wind in the polar region observed with two Fabry-Perot Interferometers"Earth, Planets and Space. vol. 51. 833-844 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] M.Ishii: "Dynamics of neutral wind in the polar regio observed with two Fabry-Perot Interferometers"Earth,Planets and Space. 51巻・8巻. 833-844 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] M.Ishii: "Dynamics of neutral wind near auroral arc" Earth, Planets and Space. (印刷中).

    • Related Report
      1998 Annual Research Report

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Published: 1998-04-01   Modified: 2016-04-21  

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