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• Main Authors: W. Hazeleger, B. Wouters, G. J. Van Oldenborgh, S. Corti, T. Palmer, D. Smith, J. Kröger, H. Pohlmann, J. -s. Von Storch, Royal Netherl, De Bilt, The Netherl
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Labrador Sea; North Atlantic; Sea ice
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.411.1444; http://www.knmi.nl/publications/fulltexts/thor_ct4.pdf

We assess the skill of retrospective multi-year forecasts of North Atlantic ocean characteristics obtained with ocean-atmosphere-sea ice models that are initialized with estimates from the observed ocean state. We show that these multi-model forecasts can skilfully predict surface and subsurface ocean variability with lead times of 2 to 9 years. We focus on assessment of forecasts of major well-observed oceanic phenomena that are thought to be related to the Atlantic meridional overturning circulation. Variability in the North Atlantic subpolar gyre, in particular that associated with the Atlantic Multidecadal Oscillation, is skilfully predicted 2-9 years ahead. The fresh water content and heat content in major convection areas such as the Labrador Sea are predictable as well, although individual events are not captured. The skill of these predictions is higher than that of uninitialized coupled model simulations and damped persistence. However, except for heat content in the subpolar gyre, differences between damped persistence and the initialized predictions are not significant. Since atmospheric variability is not predictable on multi-year time scales, initialization of the ocean and oceanic processes likely provide skill. Assessment of