Historical perspective: earlier ensembles and forecasting forecast skill

Abstract

AbstractThe history of ensemble forecasting is briefly reviewed, including the pioneering approaches of stochastic dynamical forecasting (Epstein, 1969, Tellus, 21, 739–759), Monte‐Carlo forecasting (Leith, 1974b, Monthly Weather Review, 102, 409–418), Lagged Average Forecasting (Hoffman and Kalnay, 1983, Tellus, 35A, 100–118) and Scaled LAF (Ebisuzaki and Kalnay, 1991, pp. 6.31–6.32), as well as early predictions of forecast skill (McCalla and Kalnay, 1988, pp. 634–640; Palmer and Tibaldi, 1988, Monthly Weather Review, 116, 2453–2480; Kalnay and Ham, 1989, pp. 24–27; Molteni and Palmer, 1990, Monthly Weather Review, 119, 1088–1097), and their operational results (Wobus and Kalnay, 1995, Monthly Weather Review, 123, 2132–2148). Ensembles of multiple models (aka Poor person Ensemble Prediction Systems or PEPS) are generally quite successful compared to stochastically perturbed ensembles probably because the centers that created them each try to be one of the best, if not the best, so their uncertainties in the models and the analyses are more realistic than just stochastic perturbations.