The theory ot the index cycle in the general circulation of the atmosphere

Abstract

Abstract The theory of the index cycle presented here is based on the action of the turbulent Coriolis force. Unlike the ordinary Coriolis force this force does work at a rate equal to the energy exchange between the kinetic energy of the regular motions and that of the turbulent motions. It is shown that in a rotating, differentially-heated fluid the turbulent Coriolis force generates a particular type of instability which we call “gyroturbulent instability”. Gyroturbulent instability is associated with barotropic transfer within the kinetic energy spectrum of a rotating turbulent fluid, and is connected with the conversion of kinetic energy between eddy energy and energy of mean flow as a result of the action of the turbulent Coriolis force. Gyroturbulent instability generates specific oscillations in the general circulation of the atmosphere between the state of high index with weak turbulence and that of low index with strong turbulence (the index cycle). In laboratory rotating annulus experiments, th...