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Space-time variations of equatorial Kelvin wave activity around the tropical tropopause region

Research Project

Project/Area Number 16540398
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Meteorology/Physical oceanography/Hydrology
Research InstitutionKyoto University

Principal Investigator

SHIOTANI Masato  Kyoto University, Research Institute for Sustainable Humanosphere(RISH), Professor, 生存圏研究所, 教授 (50192604)

Co-Investigator(Kenkyū-buntansha) NISHI Noriyuki  Kyoto University, Graduate School of Science, Assistant professor, 大学院・理学研究科, 助手 (00222183)
HORINOUCHI Takeshi  Kyoto University, Research Institute for Sustainable Humanosphere (RISH), Assistant professor, 生存圏研究所, 助手 (50314266)
EGUCHI Nawo  Kyoto University, Research Institute for Sustainable Humanosphere(RISH), Assistant professor, 生存圏研究所, 助手 (50378907)
Project Period (FY) 2004 – 2005
Project Status Completed (Fiscal Year 2005)
Budget Amount *help
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2005: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2004: ¥1,900,000 (Direct Cost: ¥1,900,000)
KeywordsOzone / Water vapor / Tropical atmosphere / Equatorial waves / Stratosphere-troposphere exchange / Tropopause
Research Abstract

Space-time variations of the temperature and the zonal wind around the tropical tropopause region are examined using the European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis data set (ERA-40). The spectral analysis is performed to calculate power spectra in the zonal wavenumber and frequency domain for the zonal wind data. Two spectral peaks are found : one is in a region with frequency 0.035-0.25[1/day] and zonal wavenumber 1-10 for the Kelvin wave, and the other in a region with frequency 0.011-0.035[1/day] and zonal wavenumber 1-10 for the Intraseasonal Oscillation (ISO). On the basis of these frequency-wavenumber domains the grid data are reconstructed to represent Kelvin wave and the ISO activities, and the variances are calculated from the gridded data to see space-time variations of the Kelvin wave and the ISO. The ISO activity is clearly related to the eastward propagating convections, though the Kelvin wave activity is organized around 60゜E (the western Indian Ocean) throughout the year. We selected Kelvin wave events from the reconstructed zonal wind data with a threshold of -2.938 [m/s] to see the life cycle of the Kelvin waves. Kelvin waves with high activity around 60゜E begin mostly around 30゜W to 60゜E and disappear around 60゜E to 150゜E. By performing the composite analysis for the Kelvin wave events we found that the Kelvin wave generation is closely coupled with the convective event, though the area of the Kelvin wave generation does not correspond to the active convective area such as in the western Pacific.

Report

(3 results)
  • 2005 Annual Research Report   Final Research Report Summary
  • 2004 Annual Research Report
  • Research Products

    (7 results)

All 2006 2004

All Journal Article (7 results)

  • [Journal Article] Space-time variations of equatorial Kelvin wave activity and intraseasonal oscillation around the tropical tropopause region.2006

    • Author(s)
      Suzuki, J., Shiotani, M.
    • Journal Title

      Proceedings of 3rd KAGI21 International Symposium (印刷中)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] 対流圏界面付近にみられる赤道ケルビン波と季節内振動の時空間変動2006

    • Author(s)
      鈴木順子, 塩谷雅人
    • Journal Title

      第20回大気圏シンポジウム (印刷中)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2005 Annual Research Report 2005 Final Research Report Summary
  • [Journal Article] Space-time variations of equatorial Kelvin wave activity and intraseasonal oscillation around the tropical tropopause region.2006

    • Author(s)
      Suzuki, J., Shiotani, M.
    • Journal Title

      Proceedings of 3rd KAGI International symposium 2006 (in press)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Space-time variations of Equatorial Kelvin Wave Activity and Intraseasonal Oscillation around the tropical tropopause region2006

    • Author(s)
      Suzuki, J., Shiotani, M.
    • Journal Title

      Proceedings of 3rd KAGI21 International Symposium (印刷中)

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Intraseasonal variations of water vapor and cirrus clouds in the tropical upper troposphere.2004

    • Author(s)
      Eguchi, N., Shiotani, M.
    • Journal Title

      J. Geophys. Res. 109

    • NAID

      120005860042

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Intraseasonal variations of water vapor and cirrus clouds in the tropical upper troposphere.2004

    • Author(s)
      Eguchi, N., Shiotani, M.
    • Journal Title

      J.Geophys.Res. 109

    • NAID

      120005860042

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2005 Final Research Report Summary
  • [Journal Article] Intraseasonal variations of water vapor and cirrus clouds in the tropical upper troposphere.2004

    • Author(s)
      Eguchi.N., Shiotani.M.
    • Journal Title

      J.Geophys.Res. 109

    • NAID

      120005860042

    • Related Report
      2004 Annual Research Report

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Published: 2004-04-01   Modified: 2016-04-21  

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