North Atlantic Atmosphere-Ocean Interaction on Intraseasonal Time Scales

Intraseasonal wintertime ocean-atmosphere interaction over the North Atlantic sector is examined using lagged correlation/regression analysis. Consistent with previous results,the strongest correlations between midlatitude SSTs and the extratropical atmospheric circulation occur when the atmosphere leads by ~2 weeks. However, the present results also demonstrate a coherent and statistically signicant pattern of SST anomalies over the Gulf Stream extension region that precedes changes in the leading mode of Northern Hemisphere atmospheric variability by ~2 weeks. Possible mechanisms that explain the physical relationship between variability in the Gulf Stream extension and the extratropical atmospheric circulation are discussed.