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WCRP Workshop on Extremes in Climate Prediction Ensembles (ExCPEns)

Subseasonal ∙ Seasonal ∙ Annual to Decadal ∙ Multi-decadal





       ECS Application to WCRP Workshop on ExCPEns and Training and Discussion Forum 

     (Extended Deadline by 31 July)



    ※ Registration for general participation will be open in July.


   * Please contact Ms. Suhee Han ( if you encounter any problem accessing the application links.



| Date & Place  

 25-27 (Mon-Wed) October​,  2021 for ExCPEns Workshop (online) 

 27-28 (Wed-Thu) October​,  2021 for ECS training session and discussion forum (online)


| Hosted by  

- APEC Climate Center (APCC)

- Institute for Basic Science (IBS) Center for Climate Physics (ICCP)

- ​Pusan National University


| Organized by  

- WCRP Working Group on Subseasonal to Interdecadal Prediction (WGSIP)  ​

- WCRP Grand Challenge on Weather and Climate Extremes  ​

- WWRP/WCRP Subseasonal to Seasonal Prediction Project (S2S)  


| Funded by  

- Asia-Pacific Network for Global Change Research (APN)

- World Climate Research Programme (WCRP)

- ​Pusan National University 

- ​APEC Climate Center (APCC)


| Workshop Format

-  Online only


1. Workshop on ExCPEns

| Objectives 

Weather and climate extremes have enormous impacts on society, and are becoming more severe and frequent as the world warms. Associated risks of heat waves/cold spells, droughts/floods, wind and other extremes are continually evolving in response to climate variations superimposed on forced climate changes. By providing many realizations of climate-system evolution from observation-based initial conditions, climate prediction ensembles offer a powerful tool to better quantify these risks, delineate possibilities for unprecedented extremes, and understand the underlying physical mechanisms and attribution of such events.


The purpose of this workshop is to provide a focal point for current research aimed at exploiting subseasonal, seasonal, annual to decadal and longer-term prediction ensembles to improve the prediction and understanding of extreme weather and climate events. Topics to be addressed include: 

   - prediction of specific extreme events at extended and longer ranges (>10 days) 

   - quantifying the risks of extremes, including unprecedented events, in the current and future climate 

   - impacts and physical mechanisms of unprecedented extremes in climate prediction ensembles 


This workshop specifically addresses Objective 2 of the new WCRP Strategic Plan focusing on “Prediction of the near-term evolution of the climate system” and its scientific emphasis on extremes.  


| Sessions of ExCPEns

   (1) Characterization of extremes in observations and climate prediction ensembles

Identification of extremes in observational data and climate prediction ensembles is an important aspect of assessing impact of extremes in the societal context and potential for their prediction. This session invites contributions on:

  • Review of definition and characterization of climate extremes, Methodologies for identification of extremes in observational data

  • Limitations of different observational datasets for the characterization of extremes and their influence on prediction validation. 

  • Validation of extremes in climate prediction ensembles against observational estimates

  • Quantification of biases in extremes in climate prediction ensembles and implications for prediction. Possible mechanisms for biases in simulation of extremes.      ​

   (2)​ Physical mechanisms of extremes in observations and climate prediction ensembles

Understanding of physical mechanisms and large-scale drivers for extremes is prerequisite for improving prediction of extremes. This session invites contributions on:

  • Review of mechanisms of extremes in observation

  • Identification of large-scale drivers and important feedback processes for extremes

  • Mechanisms of extremes captured by climate prediction ensembles linking predictability and their initial state dependency 

   (3) Regional climate extreme information relating to impacts, vulnerability and adaptation

Accurate and regionally well-tailored climate information has become important for early warning and risk management to adapt to more frequent and severe climate extremes. This session invites contributions on:

  • Regional climate extreme information currently used and further required to enhance early warning systems for the robust decision making to maximize the socioeconomic benefits but to minimize the cost particularly for the highly vulnerable regions/countries

  • What is the effective delivery medium and shape of climate information to promote understanding and communication with regional society?

   (4) Prediction and predictability of large-scale climate variability relevant to extreme events

Patterns of large-scale climate variability including the Madden-Julian Oscillation, El Niño-Southern Oscillation, Indian Ocean Dipole, Northern and Southern Annular Modes can increase the likelihood of climate extremes in particular regions and seasons. This session invites contributions on:

  • Using climate prediction ensembles to predict and evaluate the predictability of large-scale climate variability patterns and associated climate/Earth system extremes 

  • Nature and impacts of large-scale climate events (El Niño, etc.) more extreme than any yet observed in individual climate prediction ensemble realizations

   (5) Prediction and predictability of specific extreme events (>10 days)

There is increasing interest in the predictability and prediction of extreme weather beyond 10 days. Skillful forecasts of extreme events beyond 10 days would help develop early warning systems for better preparedness which would benefit society. However, model systematic errors make it challenging for models to adequately represent extreme events. This session invites contributions on:

  • Prediction and predictability of the onset, evolution and decay of large scale long lasting extreme events (e.g. heat or cold waves, droughts) at all time scales beyond 10 days. Case studies are welcome.

  • Prediction and predictability of changes in the probability of occurrence over a large region and large period of time of some extreme events, such as tropical cyclones, tornadoes, heavy rain episodes which individual occurrence is usually not predictable beyond 10 days

   (6) Quantifying current and future risks of climate extremes 

Observations provide just one of many potential realizations of the chaotic evolution of the climate system, and may not adequately represent current conditions in a changing climate. Realistic climate prediction ensembles overcome these limitations by providing many more realizations of potential extreme events. This session invites contributions on: 

  • Quantification of the changes of extremes in the current climate, including unprecedented events, and how these will evolve in future



2. ECS training sessions and discussion forum 

| Objectives 

As to support local capacity development, we are seeking capable Early Career Scientists (ECS) in the Asia-Pacific region to build capacities on understanding, predicting, and assessing risks and impacts of weather and climate extremes. Through this workshop, ECS will be participating in a closed training session and networking session and making a presentation during the main workshop. Through this opportunity, it is expected that ECS would enhance networking and connections to the broader global and regional research communities in the Asia-Pacific region.


The key objectives of the ECS training and networking session are;

   - Bringing together global established scientists and ECS from APN member countries, with a focus on supporting participation from APN developing nations

   - ​Building capacity of ECS in the Asia-Pacific region to understand, predict, and assess risks and impacts of weather and climate extremes 


| Activities

   (1) 1.5 day training session will consist of invited lectures on physical mechanisms of extremes and prediction and predictability of large-scale climate variability relevant to extreme events. There will be also invited lectures on introducing methodologies to identify extremes and their impacts in observation and climate prediction ensembles. This training session is open to ECS worldwide.

   - ​Session 1 : Extreme detection and prediction

​Detection of extreme events using Machine Learning

Predictability of extreme events in S2S time scale 

Extreme event attribution  

   - ​Session 2 : Projection of future climate extremes

Low likelihood high impact events assessed in AR6 WGI Chapter 4

Change of extremes assessed in AR6 WGI Chapter 11

How to use the AR6 WGI interactive Atlas for climate change studies 

   (2) A networking and discussion forum will bring together global established scientists and ECS from APN member developing countries* to enhance capacity of ECS to understand, predict, and assess risks and impacts of weather and climate extremes.

* APN developing countries : Bangladesh, Bhutan, Cambodia, China, Fiji, India, Indonesia, Lao People’s Democratic Republic, Malaysia, Maldives, Mongolia, Myanmar, Nepal, Pacific Island Countries, Pakistan, Philippines, Russian Federation, Sri Lanka, Thailand, and Viet Nam   

   (3) ECS will have a chance to make a presentation in ExCPEns Workshop.



| Scientific Organizing Committee  

June-Yi Lee (Pusan National University/ICCP, Co-chair of WCRP/WGSIP

William Merryfield (Environment and Climate Change Canada, Co-chair of WCRP/WGSIP) 

Doug Smith (UK Met Office, WCRP/Explaining and Predicting Earth System Change) 

Frédéric Vitart (ECMWF, Co-chair of WCRP/WWRP/S2S) 

Xuebin Zhang (Environment and Climate Change Canada, Co-chair of WCRP/GC-Extremes) 

Arun Kumar (NOAA, WCRP/WWRP/S2S) 

Hongli Ren (China Meteorological Administration, WCRP/WGSIP)  

Michel Rixen (WCRP)

Catherine Michaut (IPSL/UVSQ, WCRP) 

Yun-Young Lee (APCC) 


| Local Organizing Committee  

Jin-Ho Yoo (APCC) 

Sangwon Moon (APCC) 

June-Yi Lee (Pusan National University/RCCS & ICCP, WCRP/WGSIP & WCRP/EPESC Lighthouse Activity)