Abstract:
The first operational run of the ECMWF Ensemble Prediction System (EPS)
was completed twenty years ago, on the 24th of November 1992. At that
time, the EPS included a representation of initial uncertainties based
on initial-time singular vectors, had 33 members and was run
three-times a week at approximately a 200 km resolution with 19
vertical levels, for up to 10 days. Today, the system includes a more
sophisticated simulations of initial perturbations based on singular
vectors and an ensemble of data assimilations. Model uncertainties are
also simulated using two stochastic schemes. Its size has been enlarged
to 51 members. It is run twice a day for up to 15 days, coupled to a
wave model, with a resolution of approximately 30 km up to forecast day
10 and 60 km afterwards. Twice a week the system is extended with a
coupled dynamical ocean to 32 days. It includes a re-forecast suite
used to compute the model climate and to generate calibrated forecast
products such as the extreme forecast index. During this talk, the EPS
development is reviewed, recent changes are presented and plans for
future improvements are discussed.