We showed that, as the rotation rate 1/ϵ increases, the solution of the 2d Navier-Stokes equations on a rotating sphere becomes zonal, in the sense that the non-zonal component of the energy becomes bounded by ϵ . This is obtained by estimating near-resonant interactions in the nonlinear term. As a consequence, the global attractor reduces to a single stable steady state when the rotation is fast enough (but still finite).
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