Workshop on Predictability, dynamics and applications research using the TIGGE and S2S ensembles

An overview of the methodologies for representing initial uncertainties and model uncertainties in the ECMWF ensemble forecasts will be given. Initial uncertainties are represented with perturbations from an ensemble of 4D-Vars with perturbed observations and with perturbations based on singular vectors. Model uncertainties are represented with the Stochastically Perturbed Parametrization Tendency scheme (SPPT). The recent upgrade of SPPT will be described.

In 2019, exchangeable initial conditions for the atmosphere are planned to be introduced. Their benefits for ensemble development will be discussed. Last but not least, future directions for the representation of model uncertainties will be summarized.