ECMWF | Reading | 11-14 September 2017
Ensemble prediction: past, present and future
Twenty-five years ago, both the ECMWF and the US National Centers for Environmental Prediction (NCEP) started producing global, medium-range ensemble forecasts as part of their operational suites. The implementation of these ensembles induced a paradigm shift in NWP from providing a single forecast, to issuing a range of forecasts that can be used to identify possible future scenarios, to compute the probability of events of interest, and in general to estimate forecast confidence levels. Today, ensembles are routinely used to provide estimates of the probability distributions of analyses and forecasts.
During the Seminar, we discussed whether the existing ensemble designs can continue to deliver improvements, or whether we need to re-consider their configurations. We revisited the main assumptions behind the different strategies used to simulate initial and model uncertainties, and assessed whether there is clear evidence that one approach should be preferred to another. We looked at how global and regional ensembles can complement each other, and whether different ensemble techniques should be used to estimate the initial or forecast state of the atmosphere. Sources and sinks of forecast skill were also discussed.
Seminar aims
The seminar is part of ECMWF's educational programme and is aimed at young scientists but also more established scientists that want to engage more with ensemble prediction.
Presentations and recordings
Monday 11 September
| Presentation | Recording | |
| Welcome and opening Andrew Brown (ECMWF) |
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| Historical perspective: earlier ensembles and forecasting forecast skill and Global Leading Lyapunov Vectors Eugenia Kalnay (University of Maryland) |
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| Historical Review: Foundational studies in atmospheric predictability Joe Tribbia (NCAR) |
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| The ECMWF approach to ensemble prediction Tim Palmer (University of Oxford) |
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| The virtues of ensemble forecasting Zoltan Toth (NOAA/ESRL) |
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| The Canadian approach to ensemble prediction Peter Houtekamer (CMC) |
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Tuesday 12 September
| Presentation | Recording | |
| EnKF methods to initialize ensembles Neill Bowler (UK Met Office) |
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| Ensemble of data assimilation methods for the initilization of EPS Laure Raynaud (Météo-France) |
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| Combining EDA and SVs to initialize ensemble forecasts Simon Lang (ECMWF) |
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| Ensembles in the ocean: an overview Magdalena Balmaseda (ECMWF) |
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| Stochastic methods for representing atmospheric model uncertainties in ECMWF's IFS model Sarah-Jane Lock (ECMWF) |
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| Ensemble data assimilation using a unified representation of model error Chiara Piccolo (UK Met Office) |
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| Ensemble model error at Météo-France François Bouttier (Météo-France) |
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| Uncertainty quantification in ocean models Laure Zanna (University of Oxford) |
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Wednesday 13 September
| Presentation | Recording | |
| Upscale and downscale error growth Dale Durran (University of Washington) |
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| Tropical-extratropical interactions in ensemble predictions from sub-seasonal to decadal scales Franco Molteni (ECMWF) |
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| Seasonal forecast ensembles: How confident are predictability estimates of the NAO? Antje Weisheimer (ECMWF and University of Oxford) |
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| Ensemble size: how suboptimal is less than infinity? Martin Leutbecher (ECMWF) |
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| Ensemble forecast products: supporting users’ decision making David Richardson (ECMWF) |
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| Hydrological ensemble prediction Hannah Cloke (University of Reading) |
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| Slowly but surely: Observing and supporting the growing use of ensemble products Renate Hagedorn (DWD) |
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| Panel discussion: Future directions for ensemble systems | |
Thursday 14 September
| Presentation | Recording | |
| Ensemble verification metrics Debbie Hudson (BoM) |
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| Ensemble verification and extreme events Chris Ferro (University of Exeter) |
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| Diagnostics of ensemble data assimilation and ensemble forecasts Mark Rodwell (ECMWF) |
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| Diagnostic and verification of low-frequency phenomena Laura Ferranti (ECMWF) |
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| Ensembles for air quality and atmospheric composition prediction Angela Benedetti (ECMWF) |
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| Very high-resolution, non-hydrostatic, short-range ensembles Inger-Lise Frogner (Norwegian Meteorological Institute) |
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| The Forecast Skill Horizon Roberto Buizza (ECMWF) |
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| Ensembles for climate projections David Sexton (UK Met Office) |
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Organising committee
Roberto Buizza, Martin Leutbecher, Anna Ghelli, Antje Weisheimer, Franco Molteni, Magdalena Alonso-Balmaseda, Sarah-Jane Lock, Tim Stockdale, Massimo Bonavita, David Richardson.