Nonlinear structures with multivalued (q, ψ) relationships—exact solutions of the barotropic vorticity equation on a sphere

Abstract

Abstract Finite-amplitude solutions are sought to the Barotropic Vorticity Equation (BVE) on a sphere in the presence of realistic zonal flows. The new solutions are characterized by multivalued (q, Ψ) relationships, and can be constructed analytically. The resulting zonal flows and the (q, Ψ) scatter plots can be very close to climatology. Many observed flow features of the persistent anomalies, like the midlatitude westerly jetstreams and splits as well as the well-known dipole-blocking structures can be well described in terms of these new solutions. It is suggested that the observed persistent anomalies in the atmosphere may be a manifestation of these solutions being resonantly excited through thermal forcing.