On Zonal Flows in the Earth’s Outer Core

Abstract

Geomagnetic field models and their-derived models of near-surface currents in the Earth’s core (i.e., at the core-mantle boundary) exhibit structural features that correspond to periodic zonal flows. Taking into account that Rossby waves and large-scale circulation may exist near the core–mantle boundary, their interaction is analytically examined. It is shown that this interaction results in instability, driving the emergence of zonal flows and the formation of their quasi-periodic structure in the meridional direction.