NONEQUILIBRIUM RESPONSE OF THE GLOBAL OCEAN ON THE 5-DAY ROSSBY-HAURWITZ WAVE IN ATMOSPHERIC SURFACE PRESSURE

The response of rbe global ocean to the surface pressure signal associ ated with the well-known 5-day Rossby-Haurwitz atmospheric mode is exp lored using analytical and numerical tools. Solutions of the Laplace t idal equations for a flat-bottom. globe-covering ocean, point to a dep th-independent nonequilibrium response related to the near-resonant ex citation of the barotropic oceanic mode. Numerical experiments with a shallow-water model illustrate the effects of realistic continental bo undaries, topography, and dissipation on the solutions. The character of the oceanic adjustment and the structure of resonances changes subs tantially, but a nonequilibrium response occurs in all cases studied. Besides the excitation of large-scale vorticity modes or waves, which becomes less important when topography and strong dissipation are pres ent. basin-scale nonequilibrium signals are associated with gravity wa ve dynamics and the process of interbasin mass adjustment in the prese nce of. global-scale forcing and continents that require interbasin ma ss fluxes to occur through the Southern Ocean. Solutions with forcing most representative of the observed atmospheric wave agree qualitative ly with the results of analyses of Pacific and Atlantic tide gauge rec ords by Luther and Woodworth et al, The observed nonequilibrium signal s thus seem related to the Rossby-Haurwitz forcing mode.