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Shigeo Yoden (Kyoto Univ., yoden@kugi.kyoto-u.ac.jp )

Five-year research project in Japan on extreme weather variations in the stratosphere-troposphere coupled system. Shigeo Yoden (Kyoto Univ., yoden@kugi.kyoto-u.ac.jp ). 1 /17. Grants-in-Aid for Scientific Research (S) Extreme Weather Variations

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Shigeo Yoden (Kyoto Univ., yoden@kugi.kyoto-u.ac.jp )

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  1. Five-year research project in Japan on extreme weather variations in the stratosphere-troposphere coupled system • Shigeo Yoden • (Kyoto Univ., yoden@kugi.kyoto-u.ac.jp) 1/17

  2. Grants-in-Aid for Scientific Research (S) Extreme Weather Variations in the Stratosphere –Troposphere Coupled System: Past, Present and Future FY2012 - 2016 PI : Shigeo Yoden(Kyoto Univ.) Co-I : K. Ishioka, M. Taguchi, R. Mizuta, H. Mukougawa, T. Enomoto, A. Kitoh, K. Kodera, Y. Naito and T. Hirooka Postdoctoral Fellow: E. Nishimoto and S. Noda 2/17

  3. Background • Stratospheric sudden warming (SSW) • a typical extreme weather event in the S-T coupled system • highly nonlinear global- scale dynamical phenomenon • prediction is a quite difficult problem Time evolution of NP Temp. [K] at 10 hPa 2009 70 K 5 days Mukougawa et al. (2012) NP C C Time evolution of the polar vortex during an SSW event (every 3 days)

  4. Vertical couplings between S and T, and between S and M • downward propagation of a signal of extreme weather event in the stratosphere • significant influence down to the surface weather and climate • upward influence of an SSW to the mesosphere is another interesting thing • weaker mean zonal wind brings more nonlinear interactions among multi-scale waves Tides, PWs, and GWs • (e.g., Baldwin and Dunkerton 2001)  Hirooka #1312 Just after the SSW in Feb. 2007, an extreme cold event took place over North America 4/17 Mukougawa et al. (2012)

  5. Multiple time-scale variations of S-T coupled system • large day-to-day, intra-seasonal, and inter-annual variations in the Northern Hemisphere winter • highly skewed (or bimodal) PDFin monthly mean Temp. 1990s J J A S O N D J F M A M 2000s J A S O N D J F M A M J PDF of monthly mean Temp. at NP MCM experiment for 15,200 years Nishizawa and Yoden (2005) Intra-seasonal and inter-annual variation of NP Temp.Noguchi and Yoden (2012) 5/17 220 240 260 280 [K]

  6. Purpose and strategy • We aim to understand the dynamical linkage among these internal and external variations of the T-S-M coupled system comprehensively • We aim to contribute for improving our ability of prediction of extreme weather events • We investigate the feature of these internal and external variations in the current climate by analysing the observational and forecast datasets • We make validations of climate models by paleoclimatesimulations and sensitivity studies • Based on these studies for the past and present climates, we assess the impact on the future climate of the S-T coupled system with projection uncertainty

  7. Research groups (1) Data analyses M. Taguchi(Aichi U.E.), S. Yoden(KU), Y. Naito(KU), E. Nishimoto(KU), W. Randel(NCAR, US), K. Rosenlof(NOAA, US), M. Baldwin(U. Exter, UK) phenomenological description of extreme weather events (2) Mechanistic circulation model and statistical studies K. Ishioka(KU), S. Yoden(KU), S. Noda(MRI), P. Haynes(U. Cambridge, UK), A. Gettelman(NCAR, US), M. Ghil（ENS, F.) understanding their dynamical processes with a hierarchy of numerical models and construction of a new statistical law (3) GCM and NWP model studies H. Mukougawa(KU), T. Enomoto(KU), T. Hirooka(Kyushu U.), K. Kodera (Nagoya U.), T. Palmer(U. Oxford, UK), P. Hitchcock(U. Cambridge, UK) ensemble NWP experiments with long enough datasets (4) MRI climate model studies R. Mizuta(MRI), A. Kitoh(MRI), K. Yoshida(MRI), S. Noda(MRI), T. Shepherd (U. Reading, UK), Son(SNU, Korea) paleoclimatesimulations: LGM(21 ka), MH (6 ka) and LM(850–1850)

  8. EVOLVING CONCEPTIAL MODELS OBSERVATIONS DYNAMICAL MODELS COMPLEX MEDIUM SIMPLE • hierarchy of numerical models to reduce the gap between a complex real world and an idealized theory • Hoskins (1983; Quart.J.Roy.Meteor.Soc.) Dynamical processes in the atmosphere and the use of models • Held (2005; BAMS ) The gap between simulation and understanding in climate modeling THEORIES NUMERICAL EXPERIMENTS A schematic illustration of the optimum situation for meteorological research 8/17

  9. Time lines • international workshop and symposium to promote interactions among generations and regions including Asian countries 研究打合せ・成果交流のための定期的全体会議 基盤（Ａ） 現在（・未来） 基盤（Ｓ） 過去気候研究 再解析 データ解析 継続 過去・未来マルチモデル 実験データ解析 データベース 構築 過去気候 データ解析 新統計則の構築・応用 実験設定・感度 解析コード開発 大標本統計 解析、感度解析 長時間積分データ感度解析、増幅メカニズム探究 数値天気予報保管データ 詳細解析継続 モデル・データ同化 システム移植 アンサンブル 擬似予報実験 擬似予報実験 データ解析 世界古気候 再現実験 データ解析継続 縄文期 気候再現実験 最終氷期 気候再現実験 過去千年 気候再現実験 計算サーバー、データ記憶装置の補強 計算サーバー、データ記憶装置の導入 データ記憶装置の補強 データ記憶装置の補強 データ記憶装置の補強 International symposium AOGS/WPGM ｊoint年次総会 IAMAS/ICMA国際研究集会 IAMAS/ICMA国際研究集会 International workshop

  10. Japan-US (JSPS-NSF) Seminar on • Stratosphere-Troposphere Coupling • March 13 - 17, 2001 • Kyoto City Hall for International relationship, Kyoto, Japan • convened by Shigeo Yoden and William Randel 10/17

  11. SPARC Workshop on • Stratospheric Sudden Warming and its Role • in Weather and Climate Variations • February 22 (Wed) - 24(Fri), 2012 • Kyoto University, Kyoto, Japan • convened by Mark Baldwin, Ted Shepherd and Shigeo Yoden Participants from abroad 46 (14 countries), local 57 in total 105 participants, Ustream.tv viewer 428 11/17

  12. WCRP Regional Workshop on • Stratosphere-Troposphere Processes and their Role in Climate • April 1 (Mon) - 3(Wed), 2013 • Kyoto University, Kyoto, Japan • convened by Masato Shiotani and Shigeo Yoden Participants from abroad 24 (10 countries), local 56 in total 80 participants, Ustream.tv viewer 69 12/17

  13. RIMS International Conference on • Theoretical Aspects of Variability and Predictability • in Weather and Climate Systems • October 22 (Tue) - 25 (Fri), 2013 • at Masukawa Hall, Kyoto University, Japan • keynote speakers: • Michael Ghil (ENS/ UCLA, France) • Tim Palmer (U. Oxford, UK) • an international activity under “Mathematics of Planet Earth year 2013” (c) Dale Durran2005 Kuramafire festival (22nd in October, every year) 13/17

  14. Uniqueness: “wide perspective” • Paleoclimatesimulations and sensitivity studies • Last Glacier Max.(21 ka), Mid-Holocene(6 ka), and so on • Interdisciplinary collaborations with geological people JanMaySep FebJunOct MarJulNov AprAugDec • Difference of surface T: 6ka – 0ka • simulated by MRI CSM • Kitoh (2012) Geological proxy data from limestone (stalagmite) Watanabe et al. (2010)

  15. Contribution to improve numerical weather predictions • experimental NWPs with operational models and data assimilation systems • Predictability variations sensitive to the initial conditions ensemble forecast JMA one-month ensemble forecast for an SSW event in 2009 Mukougawa (2012) ー observation ー ensemble forecast (50 members) observation Initial time observation Initial time 15/17

  16. Summary • Vertical coupling: T-S-M • interactions of multiple processes • Multiple time-scales • daily - ... - multi-decadal • Hierarchy of models • simple - medium - complex • Past, present and future • LGM, MH, LM • collaborations with geological people

  17. Thank you ! 17/17

  18. 独創性及び革新性 • 成層圏突然昇温現象という極端気象を、 強非線型性な力学現象の不規則で稀な出現と認識  非ガウス型確率密度関数の先端部に関わる統計解析 複雑精緻な気候モデルではどうか ？ 過去気候ではどうだったか ？ 将来気候ではどうなるのか ？ １２月 １月 ２月 220240 260 280 [K] Nishizawa and Yoden (2005) 出現間隔の統計： ポアソン過程？

  19. 極端気象変動に関する統計則 • 従来の経験則 • 風速：　ワイブル分布 • 降雨量：　ガンマ分布 • 雲特性：　対数正規分布 • ・・・・・・ • 周極渦崩壊の形態学 • 観測事例数の不足 • 数値実験による代用 • 計算結果データに基づいて経験則をつくる • vs　演繹的な法則 • 強非線型現象の不規則で稀な出現

  20. 独創性及び革新性 • あらゆる階層の数値モデルを用いて系統的に実験 　　○ 理想化簡略化した低次元モデル(LOM) 100～101自由度；　簡単概念・定性的 　　○ 全球３次元の力学モデル(MCM) 104～106自由度；　メカニズム理解 　　○ 大気大循環モデル(GCM), 数値天気予報モデル(NPM), 気候モデル(CGCM) 106～109自由度；　複雑精緻・定量的 １９８０年代は低次元モデル、 １９９０年代からは３次元力学モデル、 これからは、複雑精緻モデルも総合的に活用

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