A hemispheric-scale quasi-decadal oscillation and its signature in Northern Japan

Pronounced quasi-decadal oscillation in surface air temperature over northe rn Japan is linked to the North Atlantic Oscillation (NAG). A NAG-based reg ression analysis reveals a hemispheric-scale decadal temperature anomaly pa ttern that features a seesaw between eastern Canada/Greenland and northern Eurasia at high latitudes, with additional centers of action in the eastern United States and North Africa/Middle East. Advection of climatological me an temperature gradient by anomalous winds seems to be a mechanism for thes e temperature anomalies. Particularly, positive temperature anomalies over Siberia at NAO's positive phase are associated with anomalous southwesterly winds on the upstream side. The advection by mean westerlies is also impor tant over Eurasia, bringing large decadal variability to northern Japan. Th is quasi-decadal oscillation can be traced farther eastward to the North Pa cific, in the Aleutian low and in sea surface temperature on the subarctic Gent. A possible inter-oceanic link between the North Atlantic and Pacific is discussed.