Investigation of Arctic mixed-phase stratus clouds with a habit-prediction scheme

• Project/Area Number: 16K17803
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Meteorology/Physical oceanography/Hydrology
• Research Institution: Kochi University of Technology (2018); Kyushu University (2016-2017)
• Principal Investigator: Hashino Tempei 高知工科大学, 環境理工学群, 准教授 (10766520)
• Research Collaborator: OKAMOTO hajime ; KOIKE makoto ; Gijs de Boer ; Greg Tripoli
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2018: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2016: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: 北極 / 混合相層雲 / 雲物理 / 数値実験 / 北極混合相層状雲 / ３次元LES / 晶癖 / 氷晶核形成 / 雲レーダ / ライダ / 氷晶核形成過程 / 北極の雲降水 / 晶癖予測雲微物理スキーム / LES / 気象学

Outline of Final Research Achievements

Clouds modulate the surface energy budget through shortwave and longwave radiation. In Arctic, low-level clouds with liquid particles prevail even at temperature less than 0 degree, and these are important for climate prediction. In this research, we evaluated a habit-prediction model that simulates ice crystal shapes (habit), and investigated relationships between habit and ice nucleation process. Comparison of the simulation against cloud radar observation indicated its effectiveness and the predicted habit was qualitatively similar to the observation. As for hexagonal plates crystals, the size of droplets freezing relates to the axis ratio of crystals after vapor depositional growth. Also, large droplets that are not yet activated play an important role in the freezing process.

Academic Significance and Societal Importance of the Research Achievements

北極の混合層層雲において、氷粒子の発生メカニズムは未解明であり、気象や気候モデルで再現が困難であるため、現在もリモートセンシング観測や現地調査により、活発に研究されている。本研究では、最新の知見を組み込んだ数値モデルを用いて、水滴の凍結現象と氷晶の形状に関係があることを示した。リモートセンシングから氷晶の形成過程を推測できる可能性がある。大きい水滴の重要性を示し、大きいエアロゾル粒子の観測の重要性を示した。また、晶癖予測モデルによる再現実験を他のモデル開発の際に参照することができる。

Research Products

• [Presentation] Traces of ice nucleation modes in Arctic mixed-phase clouds simulated by a habit prediction scheme (2018)
  • Author(s): T. Hashino, G. de Boer, H. Okamoto, G. J. Tripoli
  • Organizer: 10th international aerosol conference
  • Int'l Joint Research / Invited
• [Presentation] Impacts of immersion freezing schemes on Arctic mixed-phase clouds simulated with a habit prediction scheme (2018)
  • Author(s): T. Hashino, H. Okamoto, G. de Boer, G. J. Tripoli
  • Organizer: Japan Geoscience Union
  • Int'l Joint Research / Invited
• [Presentation] SHIPSを用いた北極混合相雲の研究 (2018)
  • Author(s): 端野典平、G. de Boer、岡本創
  • Organizer: 気象学会秋季大会
• [Presentation] Relationships between ice nucleation process and crystal habit for Arctic mixed-phase clouds; a numerical study (2018)
  • Author(s): Hashino, T., G. de Boer, H. Okamoto, and G. J. Tripoli
  • Organizer: American Meteorological Society 98th Annual Meeting
  • Int'l Joint Research
• [Presentation] 北極混合相層雲における氷晶核形成過程と晶癖分布の関係 (2017)
  • Author(s): 端野典平, Gijs de Boer, 岡本創
  • Organizer: 日本気象学会2017年秋季大会
• [Presentation] A numerical study of ice nucleation process and crystal habit for Arctic mixed-phase clouds (2017)
  • Author(s): Hashino, T., G. de Boer, H. Okamoto
  • Organizer: Japan Geoscience Union JpGU-AGU Joint Meeting
  • Int'l Joint Research
• [Presentation] 晶癖予測モデルにより再現される北極混合相層雲の評価 (2016)
  • Author(s): 端野典平、Gijs de Boer、岡本創
  • Organizer: 日本気象学会
  • Place of Presentation: 名古屋大学
• [Presentation] Evaluation of Arctic mixed-phase clouds simulated by a habit-prediction model (2016)
  • Author(s): Tempei Hashino, Gijs de Boer, Hajime Okamoto, and Gregory J. Tripoli
  • Organizer: American Geophysical Union
  • Place of Presentation: San Francisco, USA
  • Int'l Joint Research