Forecast skill of multi-year seasonal means in the decadal prediction system of the Max Planck Institute for Meteorology

We examine the latest decadal predictions performed with the coupled model MPI-ESM as part of the Coupled Model Intercomparison Project Phase 5 (CMIP5). We use ensembles of uninitialized and yearly initialized experiments to estimate the forecast skill for surface air temperature. Like for its precursor, the initialization of MPI-ESM improves forecast skill for yearly and multi-yearly means, predominately over the North Atlantic for all lead times. Over the tropical Pacific, negative skill scores reflect a systematic error in the initialization. We also examine the forecast skill of multi-year seasonal means. Skill scores of winter means are predominantly positive over northern Europe. In contrast, summer to autumn means reveal positive skill scores over central and south-eastern Europe. The skill scores of summer means are attributable to an observed pressure-gradient response to the North Atlantic surface temperatures. Citation: Muller, W. A., J. Baehr, H. Haak, J. H. Jungclaus, J. Kroger, D. Matei, D. Notz, H. Pohlmann, J. S. von Storch, and J. Marotzke (2012), Forecast skill of multi-year seasonal means in the decadal prediction system of the Max Planck Institute for Meteorology, Geophys. Res. Lett., 39, L22707, doi: 10.1029/2012GL053326.