1st Workshop of TIGGE (THORPEX Interactive Grand Global Ensemble)

The first workshop on TIGGE was held from 1 to 3 March 2005, at ECMWF. Members of the organising committee, invited speakers and working group chairs continued on Friday 4th March to write up the results of the workshop and plan the next steps.


The purpose of this workshop was to collect the views of the community on what the TIGGE science aims should be, what the requirements are for use of the TIGGE data and hence what are the infrastructure requirements. Based on the input from the workshop the TIGGE-WG will initiate the planning and development of TIGGE facility and the associated research projects.


A major research challenge of 21 century is to reduce and mitigate natural disasters and to realise the societal and economic benefits of improved weather forecasts. THORPEX will address this research challenge, thereby contributing to the development of a future truly integrated Global Interactive Forecast System (GIFS), which would generate numerical probabilistic products, available to all nations including developing countries. "Global" signifies both global participation and global application; the system would in principle use global and regional models as appropriate. An "Interactive" forecast system changes according to situation and user needs: all parts of the system from observations through data assimilation and the forecast production to the end-user applications are integrated, adaptive, and interactive.

The THORPEX Interactive Grand Global Ensemble (TIGGE) will provide the facility to test these concepts in a prototype GIFS, and at the same time provide a framework for international collaboration in the development and testing of ensemble prediction systems. TIGGE is planned to provide the main prediction tool in THORPEX Demonstration Projects. These activities will contribute to the international development and testing of the GIFS.

One of the issues that was discussed during the WS was the definition of the TIGGE Working Group (WG) that will direct and oversee the TIGGE project. The duties of the TIGGE-WG included:

  • Design structure of TIGGE dataset considering potential scientific research subprojects and possible real-time applications
  • Prioritise requirements of different subprojects
  • Monitor work and results done with TIGGE data
  • Report on progress to THORPEX, funding bodies, data providers Feed progress into development of GIFS
  • Take necessary action to ensure success of project

One of the first tasks of the TIGGE-WG was to define the scientific requirements for TIGGE and then to plan and develop the infrastructure accordingly.

The organising committee
  • Horst Boettger (ECMWF)
  • Gilbert Brunet (MSC, Canada)
  • Roberto Buizza (ECMWF)
  • Martin Ehrendorfer (Univ. Innsbruck, Austria) Renate Hagedorn (ECMWF)
  • Jim Hansen (MIT, USA)
  • Kamal Puri (BMRC, Australia)
  • David Richardson (Met Office, UK)
  • David Stephenson (Univ. Reading, UK) Yoshiaki Takeuchi (JMA, Japan)
  • Zoltan Toth (NCEP, USA)

Supporting information & documents

PDF iconParticipants

PDF iconUser requirements

PDF iconFinal report

Topics for Working Groups discussions

WG-1: Design of TIGGE experiments and model systems (chairs: Martin Ehrendorfer and Jim Hansen)

  • What are the scientific goals of TIGGE?
  • What is the strategy to achieve these goals?
  • How do we want to deal with initial uncertainties?
  • How do we want to deal with model imperfection?
  • How do initial perturbations matter?
  • Can/should we assess initial perturbations against analysis error? If Pa were available - how would we generate perturbations?

WG-2: Postprocessing and verification (chairs: Tom Hamill and Beth Ebert)

  • What post-processing techniques do we want to develop / apply?
  • What training data sets are necessary?
  • Do we need to verify ensembles or just probability forecasts derived from ensembles? How can we verify without accounting for observational uncertainty?
  • How should we verify ensemble forecasts of "objects" or "entities"?
  • Is it possible to verify a single ensemble forecast?
  • What about verifying the ensemble mean?
  • How can we convey information on the quality of ensemble forecasts to external users?

WG-3: Applications in TIGGE (chairs: Mark Roulston and Francois Lalaurette)

  • Who will have access to TIGGE data?
  • What are the specific needs of high impact weather applications? (hurricanes, floods, etc.) What are the specific needs of disaster mitigation applications? (health, environment, etc.) What are the specific needs of economic applications? (energy, agriculture, finance, tourism, etc.)
  • What are the specific user requirements in developing countries?
  • What information on forecast quality/credibility is needed?

WG-4: Infrastructure of TIGGE (chairs: Horst Boettger and Laurie Wilson)

  • Development of a priority list of user requirements
  • Development of strategy to facilitate user requirements
  • What resources are necessary? (bandwidth, hardware, software, tools, archiving strategy/policy)
  • What are the costs?
  • Development of agreement on data volume and structure Development of management structure and contractual agreement


Tuesday 1 March  

Welcome and opening

D Marbouty


Introduction to THORPEX / TIGGE

D Richardson

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Overview of global operational ensembles

R Buizza

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Initial perturbations in ensemble prediction

M Ehrendorfer

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Model imperfections

T Palmer

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T Hamill

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E Ebert

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Limited area ensemble systems

T Paccagnella

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Applications: forecaster perspective, training

K Mylne

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Wednesday 2 March  

Applications: weather driven natural hazards

J Thielen

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Applications: economics, energy, risk management

M Roulston

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NAEFS: scientific and technical issues

Z Toth

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Infrastructure and tools

F Hofstadler

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User experience and requirements

R Hagedorn

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An architecture for a User-centric Global Interactive Forecast System testbed

L Treinish

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Thursday 3 March  
Plenary: preliminary reports from WGs and new brief -
Working groups: revision of recommendations -
Plenary: revised reports from WGs, and final discussion -
Friday 4 March  
Organising Committee, speakers, WG chairs only -