Observed influence of ocean circulation variability on the atmospheric circulation in the cold season (Invited Presentation)

Observed evidence of an influence of the decadal variability of the ocean circulation on the atmosphere will be discussed in two cases. In the North Atlantic, a SST anomaly pattern that closely resembles the Atlantic Multidecadal Oscillation (AMO), driven in climate models by the Atlantic meridional overturning circulation, will be shown to lead at low frequency a negative phase of the NAO in winter. In the North Pacific, the decadal variability of the Kuroshio Extension will be shown to significantly influence the northern hemisphere atmospheric circulation in the cold season. Main mechanisms of these air-sea interactions will be discussed.