The seasonal-to-decadal (s2d) experiments comprise two sets of simulations: the so-called Stream 1 and Stream 2 simulations. For both streams, coordinated forecast experiments over seasonal, interannual and decadal timescales have been performed. Three different approaches are being pursued to represent model uncertainties: the multi-model approach, the perturbed physical parameter approach and the stochastic physics approach.

Description of the s2d experiments

• 2 start dates per year: 1st of May and November
• 7 month hindcasts for May and 14 for November
• Hindcast production 1991-2001
• 9-member ensembles
• Multi-annual ensemble integrations
• Two hindcasts started on the first of November 1965 and 1994

• 4 start dates per year: 1st of February, May, August and November
• 7 month hindcasts for every start date, except 14 for those starting in November
• Hindcast production 1960-2005, using ERA-40 up to August 2002 inclusive and ECMWF operational analyses afterwards
• 9-member ensembles
• Multi-annual ensemble integrations(minimum set)
• One hindcast every 5 years
• 10 year runs starting on 1st of November 1960, with the next one starting in November 1965 and so on
• Hindcast production 1960-2005
• 3-member ensembles