1. ® Sponsored by WMS BP for Ensemble Marie-Francoise Voidrot-Martinez and Chris Little Co chairs Met Ocean DWG

2. OGC ® What are Ensemble Forecasts? Copyright © 2014 Open Geospatial Consortium 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

3. OGC ® 1st 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

4. OGC ® Consensus 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) Copyright © 2014 Open Geospatial Consortium –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)

5. OGC ® Consensus 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

6. OGC ® On 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

7. OGC ® 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 Copyright © 2015 Open Geospatial Consortium

8. OGC ® Thank you to listen carefully : we wish a productive discussion Copyright © 2015 Open Geospatial Consortium