Real-time multi-model decadal climate predictions

We present the first climate prediction of the coming decade made with multiple models, initialized with prior observations. This prediction accrues from an international activity to exchange decadal predictions in near real-time, in order to assess differences and similarities, provide a consensus view to prevent over-confidence in forecasts from any single model, and establish current collective capability. We stress that the forecast is experimental, since the skill of the multi-model system is as yet Electronic supplementary material The online version of this unknown. Nevertheless, the forecast systems used here are based on models that have undergone rigorous evaluation and individually have been evaluated for forecast skill. Moreover, it is important to publish forecasts to enable open evaluation, and to provide a focus on climate change in the coming decade. Initialized forecasts of the year 2011 agree well with observations, with a pattern correlation of 0.62 compared to 0.31 for uninitialized projections. In particular, the forecast correctly predicted La Niña in the Pacific, and warm conditions in the north Atlantic and USA. A similar pattern is predicted for 2012 but with a weaker La Niña. Indices of Atlantic multi-decadal M. Ishii Meteorological Research Institute, Japan Meteorological Agency, Tsukuba 305-0052, Japan M. Kimoto Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa 277-8568, Japan B. Kirtman RSMAS/MPO, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA J. Lean Space Science Division, Naval Research Laboratory, Washington, DC 20375, USA D. Matei Á W. A. Müller Á H. Pohlmann Max-Planck-Institut für Meteorologie, Bundesstraße 53, 20146 Hamburg, Germany A. Rosati Geophysical Fluid Dynamics Laboratory, Princeton University, Princeton, NJ, USA