On the effect of ensemble size on the discrete and continuous ranked probability scores



Four recent papers have investigated the effects of ensemble size on the Brier score (BS) and discrete ranked probability score (RPS) attained by ensemble-based probabilistic forecasts. The connections between these papers are described and their results are generalized. In particular, expressions, explanations and estimators for the expected effect of ensemble size on the RPS and continuous ranked probability score (CRPS) are obtained. Copyright © 2008 Royal Meteorological Society