WWRP working group on Predictability, Dynamics & Ensemble

Forecasting (PDEF) Presenter: John Methven, University of Reading

Co-Chairs: Richard Swinbank and Craig Bishop

}  Born from the end of the THORPEX programme (2004-2014) }  Mission: “to accelerate improvements in the accuracy of one-day

to two-week high impact weather forecasts”

}  THORPEX had 4 working groups: ◦  PDP – predictability and dynamical processes ◦  TIGGE/GIFS – construction of a global interactive forecasting system ◦  DAOS – data assimilation and observing systems ◦  SERA – societal and economic research applications

}  THORPEX legacy projects ◦  PPP - Polar prediction project ◦  S2S - Subseasonal to seasonal prediction ◦  HIW - High impact weather (kick-off meeting April 2016)

}  To advance the science of dynamical meteorology and predictability research, and application to ensemble forecasting

}  To improve ensemble prediction systems

}  To support WWRP projects with expertise ◦  Polar prediction project ◦  Subseasonal to seasonal prediction ◦  High impact weather

}  To promote the utilisation of ensemble datasets ◦  TIGGE (The International Grand Global Ensemble) ◦  TIGGE-LAM ◦  Other ensemble datasets from WWRP projects

Co-chairs ◦  Craig Bishop – NRL, USA ◦  Richard Swinbank – Met Office, UK  

Members ◦  Oscar Alves – CAWCR, Australia ◦  Judith Berner – NCAR, US ◦  Masayuki Kyouda – JMA, Japan ◦  Zhiyong Meng – U Peking, China ◦  John Methven – U Reading, UK ◦  Mark Rodwell – ECMWF, International ◦  Olivia Rompainnen-Martius – U Bern, Switzerland ◦  Susanne Theis – DWD, Germany ◦  Munehiko Yamaguchi – JMA/MRI, Japan ◦  Yuejian Zhu – NCEP, USA

Ex officio ◦  TIGGE panel chair: Manuel Fuentes – ECMWF, International

PDEF WG first meeting Karlsruhe, 21-22 May 2015

1.  Stochastic representation of the effect of sub-grid-scale uncertainty in numerical models

2.  Construction of ensemble initial conditions

3.  Role of diabatic processes in dynamics and predictability

4.  Assessment of multi-model ensembles and calibration techniques

5.  Coupled modelling & data assimilation

1.  Blocking workshop (with SPARC) in Reading, UK, 6-8 April 2016 – see SPARC website:

2.  Stochastic physics workshop (with WGNE) Timing and venue yet to be confirmed

3.  Role of diabatic processes in dynamics and predictability Proposed workshop at Royal Meteorological Society conference, July 2016 – Manchester, UK

4.  North Atlantic Waveguide and Downstream Impacts Experiment (NAWDEX) Observing (non-local) influence of diabatic processes on jet stream disturbances and their impact on downstream predictability. Campaign with aircraft spanning North Atlantic & enhanced obs in W. Europe in Sept/Oct 2016.

YOPP objectives connecting most strongly with PDEF 1.  Field programmes – understanding of polar processes

2.  Representation of processes in uncoupled and coupled models

3.  Data assimilation coping with challenges of polar regions: Ø  Sparseness of observational data Ø  Importance of coupling with sea ice, ocean and land surface

4.  Predictability of coupled systems (timescales days to season)

5.  Linkages between polar regions and lower latitudes

6.  Improve verification for polar weather prediction

Possible role of PDEF WG in YOPP Ø  Design of ensembles for polar regions

Ø Obtaining IC spread in global ensembles for polar regions Ø Challenges in coupled data assimilation: coupled error

covariance, model error, … Ø Polar LAM ensemble systems

Ø  Dynamics on mesoscale and finer Ø Design of model and “tuning” for polar regions Ø Consideration of resolution for forecast system

Ø  Evaluation of ensemble prediction systems in polar regions Ø How to evaluate ensembles and value of coupling? Ø Design of scale-dependent verification diagnostics

Ø  Design of the YOPP Data Archive System Ø Arctic-LAM forecasts hosted by TIGGE-LAM?