1. Proposed Predictability, Dynamics & Ensemble Forecasting Expert Team
Richard Swinbank
Masayuki Kyouda
GIFS-TIGGE WG, Exeter, June 2013

2. Contents Post-THORPEX plans Evolution of GIFS-TIGGE
Proposed expert team
Discussion…

3. WWRP structure 3 3

4. Legacy THORPEX Subseasonal to Seasonal Prediction Project
PCPI
WGSIP
MJO TF
WGDAOS
Subseasonal to Seasonal Prediction Project
WGPDP
JWGFVR
WGNR
/MFR
Polar Prediction
Project
High Impact Weather Project
WGNE
SWFDP
WGSERA
WGTMR 4 4

5. WWRP structure and links to WCRP5 5

6. TIGGE – Research focus
The TIGGE project (& GIFS-TIGGE working group) was originally focused on the technical work enabling the establishment of the TIGGE archive dataset. The main scientific aspects of THORPEX were covered by Predictability & Dynamical Processes WG, and also Data Assimilation & Observing Systems WG(s).
Following the successful establishment of the TIGGE dataset, the focus of the GIFS-TIGGE working group has shifted towards research on ensemble forecasting. Particular topics of interest include:
a posteriori calibration of ensemble forecasts;
combination of ensembles produced by multiple models;
research on and development of probabilistic forecast products.
More recently, we have broadened our range of interest to cover improvement of EPSs, including:
representing uncertainties in initial conditions
stochastic physics & other techniques to account for model error

7. Virtuous Circle Develop, Improve Evaluate, Diagnose Ensemble Forecasts
To improve EPSs we need to develop a virtuous circle – best with a single group with focus on ensemble prediction

8. Evolution of TIGGE & GIFS
TIGGE development
Calibration, combination, products
EPS improvement
Time
GIFS-TIGGE should also be a forum to focus on R&D directed at improving our EPS systems, to help us develop a “virtuous circle”.
We introduced a section of the WG meeting for discussing ensemble initial conditions, stochastic physics & other aspects of improving our EPSs.
We also need to maintain an interest in ensemble verification & links with convective-scale EPS and the new sub-seasonal to seasonal group.

9. Looking forward - A proposed new working group
The logical evolution of an increased focus on research would be the creation of a Predictability Dynamics & Ensemble Forecasting working group, combining much of the current GIFS-TIGGE and PDP groups.
This new group would provide a centre of scientific expertise on dynamics, predictability and ensemble forecasting that is currently lacking in the core WWRP programme.

10. Scope
A centre of scientific expertise on dynamics, predictability and ensemble forecasting
Bridge between academic & operational communities
Promote use of TIGGE and TIGGE-LAM
Scientific issues include
Growth & evolution of errors
Stochastic representation of unresolved processes
Short- to medium-range forecast timescales (potentially longer)

11. Relationship with other teams / groups
Clear linkages with WGNE and other WWRP expert teams
Numerical modelling, ensembles, data assimilation, stochastic parameterization & evaluation all closely linked on weather forecast & climate timescales.
Too big for a single expert team – need a set of more specialised teams.
Providing expert support to WWRP projects (S2S, PPP, HIW, RDPs & FDPs)

12. Other issues Development of severe weather products
Would fit well into scope of proposed HIW project
Technical management of data archives
Ongoing management could be done by a liaison group of archive centres & some or all data providers.
Could report to PDEF team (or HIW project)? Representative of technical group on ET.
Transition arrangements
Work towards merger of GIFS-TIGGE and PDP groups at end of 2014
New members of both groups chosen for role in new team.

13. Next Steps
Discuss here and at joint THORPEX/ICSC and WWRP/JSC meeting.
What is the process for approving the new group?