North Atlantic decadal predictability

COLLINS M., A. F. CARRIL, H. DRANGE, H. POHLMANN, R. SUTTON AND L. TERRAY

CLIVAR Exchanges

WCRP

Año: 2003 vol. 28 p. 1 - 3

There is increasing evidence (from both observations (e.g.Koltermann et al., 1999) and models (e.g. Dong andSutton, 2001)) of decadal time-scale fluctuations in thecirculation of the Atlantic Ocean. Variations in the meridionaloverturning circulation (MOC) may impact onthe surface climate of both the ocean and the atmospherethrough changes in the northward transport of heat bythe ocean. Predictions of such decadal variations couldbring considerable benefit to society, yet these remainunrealised partly because previous studies of predictabilityhave revealed low levels of potential skill (Griffiesand Bryan, 1997; Grötzner et al., 1999). This study representsan assessment of the potential predictability of variationsin MOC and associated Sea Surface Temperature(SST) anomalies in a range of recent coupled atmosphereocean-sea ice models. It is found that, while differentmodels do produce different estimates of predictability,some models show high levels of potential skill on timescalesof decades and longer that may, one day, be exploitedby forecasters.