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

Five-year research project in Japanon

extreme weather variationsin the stratosphere-troposphere

coupled system

1/17

Grants-in-Aid for Scientific Research (S)

Extreme Weather Variationsin 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

Time evolution of NP Temp. [K] at 10 hPa

70 K

Mukougawa et al. (2012)

5 days

2009

BackgroundStratospheric 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 the polar vortex during an SSW event (every 3 days)

CC

NP

3/17

Vertical couplings between S and T, and between S and Mdownward propagation of a signal of extreme weather event

in the stratosphere

4/17

Just after the SSW in Feb. 2007, an extreme cold event took place over North America

significant influence down to the surface weather and climateupward influence of an

SSW to the mesosphere is another interesting thing

weaker mean zonal wind brings more nonlinear interactions among multi-scale wavesTides, PWs, and GWs

Mukougawa et al. (2012)

(e.g., Baldwin and Dunkerton 2001)

Hirooka #1312

220 240 260 280 [K]

JJASONDJFMAM

PDF of monthly mean Temp. at NPMCM experiment for 15,200 years Nishizawa and Yoden (2005)

2000s

1990s

Intra-seasonal and inter-annual variation of NP Temp. Noguchi and Yoden (2012)

J A S O N D J F M A M J

Multiple time-scale variations of S-T coupled systemlarge day-to-day, intra-seasonal, and inter-annual variations

in the Northern Hemisphere winter highly skewed (or bimodal) PDF in monthly mean Temp.

5/17

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 paleoclimate simulations 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

6/17

Purpose and strategy

(1) Data analysesM. 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 studiesK. 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 numericalmodels and construction of a new statistical law

(3) GCM and NWP model studiesH. 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 studiesR. Mizuta(MRI), A. Kitoh(MRI), K. Yoshida(MRI), S. Noda(MRI), T. Shepherd (U. Reading, UK), Son(SNU, Korea)paleoclimate simulations: LGM(21 ka), MH (6 ka) and LM(850–1850) 7/17

Research groups

OBSERVATIONS

DYNAMICAL MODELSCOMPLEX MEDIUM SIMPLE

EVOLVINGCONCEPTIAL MODELS

A schematic illustration of the optimum situation for meteorological research

THEORIES

NUMERICAL EXPERIMENTS

8/17

hierarchy of numerical models to reduce the gap between a complex real world and an idealized theoryHoskins (1983; Quart.J.Roy.Meteor.Soc.)

Dynamical processes in the atmosphere and the use of modelsHeld (2005; BAMS )

The gap between simulation and understanding in climate modeling

Time lines

研究班と諸計画 2012 2013 2014 2015 2016

（１）データ解析班

（２）力学モデル・統計班

（３）大気大循環・ 数値天気予報モデル班

（４）気候モデル班

主な設備備品購入計画

国際研究集会の計画

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

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

データ記憶装置の補強

データ記憶装置の補強

計算サーバー、データ記憶装

置の補強

研究打合せ・成果交流のための定期的全体会議

データベース構築

実験設定・感度

解析コード開発

モデル・データ同化

システム移植

縄文期気候再現実験

大標本統計解析、感度解

析

最終氷期気候再現実験

擬似予報実験データ解析

新統計則の構築・応用 長時間積分データ感度解

析、増幅メカニズム探究

過去気候データ解

析

再解析データ解

析継続

世界古気候再現実験

データ解析継続

数値天気予報保管データ

詳細解析継続

基盤（Ａ）現在（・未

来）

基盤（Ｓ）過去気候研究

international workshop and symposium to promote interactions among generations and regions including Asian countries

International symposium

過去・未来マルチモデル実験データ解析

アンサンブル

擬似予報実験

過去千年気候再現実験

9/17

Japan-US (JSPS-NSF) Seminar onStratosphere-Troposphere Coupling

March 13 - 17, 2001Kyoto City Hall for International relationship, Kyoto, Japanconvened by Shigeo Yoden and William Randel

10/17

SPARC Workshop onStratospheric Sudden Warming and its Role in Weather and Climate Variations

February 22 (Wed) - 24(Fri), 2012Kyoto University, Kyoto, Japanconvened by Mark Baldwin, Ted Shepherd and Shigeo Yoden

Participants from abroad 46 (14 countries), local 57in total 105 participants, Ustream.tv viewer 428 11/17

WCRP Regional Workshop onStratosphere-Troposphere Processes and their Role in Climate

April 1 (Mon) - 3(Wed), 2013Kyoto University, Kyoto, Japanconvened by Masato Shiotani and Shigeo Yoden

Participants from abroad 24 (10 countries), local 56in total 80 participants, Ustream.tv viewer 69 12/17

RIMS International Conference onTheoretical Aspects of Variability and Predictabilityin Weather and Climate Systems

October 22 (Tue) - 25 (Fri), 2013at Masukawa Hall, Kyoto University, Japankeynote speakers:

Michael Ghil (ENS/ UCLA, France)Tim Palmer (U. Oxford, UK)

an international activity under “Mathematics of Planet Earth year 2013”

(c) Dale Durran 2005Kurama fire festival (22nd in October, every year)

13/17

Paleoclimate simulations and sensitivity studiesLast Glacier Max.(21 ka), Mid-Holocene(6 ka), and so onInterdisciplinary collaborations with geological people

14/ 17

Uniqueness: “wide perspective”

Jan 　　　　　　　　 May 　　　　　　　

　 Sep

Feb 　　　　　　　　 Jun 　　　　　　　

　 Oct

Mar 　　　　　　　　 Jul 　　　　　　　　

　 Nov

Apr 　　　　　　　　 Aug 　　　　　　　

　 Dec

Difference of surface T: 6ka – 0kasimulated by MRI CSMKitoh (2012)

Geological proxy data from limestone (stalagmite) Watanabe et al. (2010)

15/17

Initial time

Initial time

observation

Contribution to improve numerical weather predictionsexperimental NWPs with operational models and data

assimilation systems Predictability variations sensitive to the initial conditions

ensemble forecastJMA one-month ensemble forecast for an SSW event in 2009 Mukougawa (2012)

ー observation ー ensemble forecast

(50 members)

observation

Vertical coupling: T-S-Minteractions of multiple processes

Multiple time-scalesdaily - ... - multi-decadal

Hierarchy of modelssimple - medium - complex

Past, present and futureLGM, MH, LMcollaborations with

geological people

Summary

16/17

Thank you !

17/17

独創性及び革新性① 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 ？

18/17

220 240 260 280 [K]

１２月

１月

２月

Nishizawa and Yoden (2005)

出現間隔の統計：ポアソン過程？

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

19/17

独創性及び革新性② 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

20/17