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

• Published in: Geophysical Research Letters
• Main Authors: Müller, W., Baehr, J., Haak, H., Jungclaus, J., Kröger, J., Matei, D., Notz, D., Pohlmann, H., von Storch, J., Marotzke, J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2012
• Subjects: Pacific; North Atlantic
• Online Access: http://hdl.handle.net/11858/00-001M-0000-0010-1B37-1; http://hdl.handle.net/11858/00-001M-0000-000E-F3D6-4

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 initialisation 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 initialisation. 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.