ARCTIC OSCILLATION AND INTERANNUAL VARIATIONS IN SEA SURFACE TEMPERATURE IN THE ATLANTIC AND PACIFIC OCEANS

E. A. Zhadin

Correlations between the anomalies of sea surface temperature (SST) in the Atlantic and Pacific oceans and the variations in the circulation of stratospheric vortex over the Arctic which is associated with the Arctic Oscillation are considered for January 1979-1992. It is shown that interannual variations in the stratospheric angular momentum in the Arctic had a dipole-like structure in the western and eastern Arctic that is attributed to a longitudinal asymmetry in a stratospheric warming impact on zonal stratospheric winds. Strong correlations of stratospheric vortex variability over the Arctic with a well-defined spatial pattern of SST anomalies in the North Atlantic and North Pacific were found. This spatial pattern is characterized by dipole SST variations at the centers of action south of Aleutes and near the Newfoundland (dipole through the Rocky Mountains) and the well-known SST anomalies in the Atlantic which are associated with the North Atlantic Oscillation (NAO). The mechanism of external generation of the Arctic Oscillation and variations in the stratospheric vortex over the Arctic can be explained by the effect of interannual SST variations in the dipole through the Rocky Mountains on a thermal excitation of stationary planetary waves and its interference with the orographic source. Relations between the interannual variability of the stratospheric vortex over the Arctic and the Arctic Oscillation and the observed ozone variations at high latitudes of the Northern Hemisphere are discussed.

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