6. Summary
A linear dynamic ocean-atmosphere coupling model that includes both the Bjerknes and WES feedbacks is developed. Our major findings may be summarized as follows.
a) The monopole and dipole emerge as independent eigenmodes of the coupled model, due respectively to the Bjerknes and WES feedbacks;
b) The existence of a dipole mode in the Atlantic is further demonstrated in a COADS-wind forced simulation that successfully reproduces observed quasi-decadal oscillatlon in interhemispheric SST gradient including its phase;
c) The dipole is likely more visible in a small basin like the Atlantic than in the larger Pacific due to the differences in growth characteristics between the monopole and dipole modes;
d) The monopole is equatorially trapped in the Pacific while it has a broad meridional scale in the Atlantic because of the difference in its growth rate between the two oceans.
e) We established from observations that there is a quasi-decadal oscillation linking the North Atlantic and Pacific in high-latitudes. This has important implications for climate prediction in both the northeastern Asia and North America.
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