Circumpolar jets emerging in two-dimensional non-divergent decaying turbulence on a rapidly rotating sphere

A series of numerical experiments on two-dimensional decaying turbulence are performed for a non-divergent fluid on a rotating sphere, with attention focused on scaling properties of spontaneous circumpolar jets. The numerical calculations show that strong circumpolar westward (retrograde) jets emerge clearly in high latitudes at a large rotation rate Ω. A scaling theory is proposed for the jet width proportional to Ω-1/4, and the jet strength to Ω1/4, which agrees well with the numerical results. A noteworthy asymptotic feature is that kinetic energy is entirely concentrated on the circumpolar jets under large rotation rates.