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Sponsored by

WMS BP for Ensemble WMS BP for Ensemble

Marie-Francoise Voidrot-Martinez and Chris LittleCo chairs Met Ocean DWG

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What are Ensemble Forecasts?What are Ensemble Forecasts?

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• A set of parallel forecasts for the same times and locations. • They are an effective use of highly parallel computers. • They are a based on a set of equally likely perturbations of

one initial state, each of which is used to calculate a forecast

• A member : one forecast out of an Ensemble Forecast set

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1st draft1st draft

• MODWG_WMS1-3_Best_Practice_Ensembles_v0.3.1.doc• Initiated by Chris and Jurgen• Same structure as Time and elevation BP

– Presentation of the specificities and uses of the data– Main use cases– Requirements and recommendations

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Consensus on 2 families of Use CasesConsensus on 2 families of Use Cases

–For met professionals:• 1 member out of n• Distributed multimodel• Multimodels in 1 location • Distributed ensemble model (maybe not realistic)

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–For decision support :• EPS derived products:

probabilities, spaghettis, clustering

• A spaghetti chart of a four day forecast for the North Atlantic which approximates the thickness of the lower atmosphere, as a proxy for average temperature.

• 500 hPa height ensemble forecast for 2001-02-11, 12:00 UTC (T+96 from 2001-02-07, 12:00 UTC)

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Consensus on 2 families of Use CasesConsensus on 2 families of Use Cases

– For met professionals:• 1 member out of n• Distributed multimodel• Multimodels in 1 location • Distributed ensemble model (maybe not realistic)

– For decision support :• EPS derived products: probabilities, spaghettis, clustering

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On the implementation sideOn the implementation side

• Focussing first on the second family of Use Cases of statistical products for decision support

• 4 different implementations used in– AFWA – DWD– Meteo-France– ECMWF

• A Proposal to introduce a more innovative and powerful syntax made by Peter Baumann

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Which means Which means

• That we really need Best Practices !

• We would appreciate some « deeper » expertise about the pros and cons of each solution

• Presented in Met Ocean DWG AND WMS SWG

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Thank you to listen carefully : Thank you to listen carefully : we wish a productive discussion we wish a productive discussion

Copyright © 2015 Open Geospatial Consortium