Abstract

The study considers a pair of sub-polar rings of atmospheric mass, symmetric with respect to the equator, and rotating with respect to the distant stars. Gravitational forces of the sun and moon exert a continuous torque on the rings. In the absence of adequate mixing and dissipation, geometrical constraints support a hypothesis of system response in the form of precession. Analysis follows the classical mechanics of rigid body rotation and the precession of the equinoxes. Results yield a mean period of precession ranging generally over decadal and centennial time scales depending on latitude. A scaling relation yields a mean period of 37 years for rings at 60 degrees North and South, while an alternate calculation more specific to the 2-ring system yields a period of 43 years for rings at 68 degrees North and South. The global net torque is negligible, but only because there is a large cancellation between high and low latitudes. The result suggests a path of investigation aimed toward im- proved projection of decadal variability in atmospheric circulation, and by extension, ocean circulation and climate.