Impact of stratospheric dynamics on climate -Deepening understandings of dynamical coupling processes between statosphere and troposphere-

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K03743
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 17020:Atmospheric and hydrospheric sciences-related
• Research Institution: Kyushu University
• Principal Investigator: Eguchi Nawo 九州大学, 応用力学研究所, 助教 (50378907)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 成層圏対流圏間相互作用 / 熱帯対流圏界面遷移

Outline of Final Research Achievements

The purpose of this study is to clarify the influence of the stratospheric dynamic process on tropical convection from a long-term perspective. 1) Using a global non-hydrostatic numerical model, it was clarified that the response of the stratospheric dynamics differs from region to region of tropical convection activity when the sudden stratospheric warming (SSW) event occurs. In addition, comparison between experiments on the presence or absence of SSW, and tropical convection becomes active when the SSW occurs.　2) From long-term satellite observations and reanalysis data, it was suggested that long-term variation in convection on the African continent can be explained by the stratospheric cooling effect.　3) It was clarified that there is a difference in the developmental difference of the cloud convection activity in the ocean continental region in the northern hemisphere winter due to the east-west wind phase change of quasi-biannual oscillation.

Free Research Field

大気科学

Academic Significance and Societal Importance of the Research Achievements

現在の気候の再現および将来気候の予報をより正確に実施するには、現在ほとんどの気候モデルで陽に解かれていない成層圏の循環場がどのように対流圏に影響を与えるのかを理解し、それを数値モデルに組み込むかが重要な課題である。特に積雲対流活動が活発な熱帯域は成層圏循環場の上流と深く結合しているため、ここでの成層圏と対流圏間の力学的相互作用過程を理解することが求められている。本研究の成果によって、これまでの見方とは異なる、成層圏の循環場による熱帯域の長期的な積雲活動への影響の新たな知見が得られただけでなく、今後の発展研究において、数値モデルの改善に繋がる成果が得られたと考えられる。