Fluid Dynamics in Earth and Planetary Sciences (FDEPS)
26th FDEPS workshop, Dec. 1 - Dec. 4, 2026 at Kansai Seminar House

[English page is here]

第 26 回ワークショップ「地球惑星科学における流体力学」

日程:
2026 年 12 月 1 日(火)〜12 月 4 日(金)

共催:
  • Research Institute for Mathematical Sciences (RIMS), Kyoto University (京都大学 数理解析研究所)
  • Center for Planetary Science (CPS) (惑星科学研究センター)
場所:
関西セミナーハウス
京都市左京区一乗寺竹ノ内町23
TEL:075-711-2115, FAX:075-701-5256

まもなく参加申し込み受付をナウンスする予定です.

プログラム

講師: Prof. Ulrich Achatz (大気力学・気候学理論教授, フランクフルト・ゲーテ大学大気・環境研究所)

  • 連続講義と自由討論 : Waves and mean flows: Multi-scale interactions in the atmosphere
    • 12/1(火)
      • 9:00 - 12:00
        Lecture 1. Rossby-wave mean-flow interactions / Gravity waves in an atmosphere at rest 1 - energetics
      • 14:00 - 17:00
        Lecture 2. Gravity waves in an atmosphere at rest 2 / Gravity-wave mean-flow interactions 1 - scale analysis
      • 夜間:<自由討論>
    • 12/2(水)
      • 9:00 - 12:00
        Lecture 3. Gravity-wave mean-flow interactions 2
        • WKB theory, eikonal equations and first nonlinear results
      • 午後:<自由討論>
      • 夜間:<自由討論>
    • 12/3(木)
      • 9:00 - 12:00
        Lecture 4. Gravity-wave mean-flow interactions 3
        • wave action, extended quasigeostrophic theory and energy conservation
      • 14:00 - 17:00
        Lecture 5. Gravity-wave mean-flow interactions 4
        • potential-vorticity conservation, non-acceleration and middle-atmosphere impact
      • 夜間:<自由討論>
    • 12/4(金) 研究セミナー
      • 10:00 - 12:00
        Research Seminar : Gravity waves: Parameterization beyond classic paradigms, including interactions with tracers, turbulence and clouds
        Atmosphere and ocean sciences are faced by substantial efforts to develop climate models resolving horizontal motions on the km scale. This will provide dynamically consistent data that can be used for detailed studies of a wealth of processes. Geophysical fluid dynamics with all its mathematical tools will be an essential element in these developments. Without it we would be left with admiring the shear complexity we are confronted with and describing selective details that catch our interest, while not being able to understand the grand picture in a conceptually satisfying way. Mathematical theory should accompany both idealized and local process studies and global-scale investigations to provide the understanding we need for the competence that our advice to policy makers should rest on. A line of research in this context addresses the dynamics of atmospheric gravity waves. They are known to both have leading-order global-scale effects on the atmospheric circulation and influence the distribution of water vapor, ice, and other substances of relevance for the climate impact of solar radiation. At the same time, they are both influenced by and affecting various other small-scale components of the atmosphere, e.g. turbulence and clouds. Such aspects are being studied using a Lagrangian approach to parameterizing gravity waves by predicting their three-dimensional propagation and formulating their mean-flow impact. The theory and numerical approach of this Multi-Scale Gravity-Wave Model MS-GWaM is continuously being developed and validated in idealized simulations, using an in-house flow solver, but MS-GWaM has also been implemented into the climate model ICON to investigate global-scale gravity-wave effects. It differs from conventional approaches for gravity-wave parameterization by taking into account effects of wave-mean-flow transience, oblique propagation, and unbalanced large-scale flows. All can be shown to matter to leading order. Other recent developments to be reported are the incorporation of gravity-wave effects on tracer transport and mixing, on turbulence, and on ice clouds. Multi-scale asymptotic theory has been used to formulate a gravity-wave Stokes drift, predominant in the presence of rotation, and a next-order coupling that might be more relevant in the tropics. In addition, a theory for the coupling between gravity waves and turbulence has been developed that accounts for the organization of turbulence within gravity waves a well as the large-scale turbulence source from small-scale gravity-wave shear. This leads to a self-consistent description of gravity-wave breaking and its effects on tracer mixing. Finally, the effect of gravity waves on ice clouds shall be touched, where asymptotic theory has been used to formulate the effect on ice nucleation without having to resolve this process in time. Investigations using ICON indicate a significant effect of convectively generated gravity waves on cirrus in the tropical tropopause layer.