Analytical Modons in Hyperbolically Sheared Zonal Flow

Abstract

   Modons in hyperbolically sheared zonal flow are analytically constructed in the equivalent barotropic system on a β plane. Linearity between the potential vorticity and the stream function, and circularity of the modon boundary are assumed. In the presence of the shear, the azimuthal velocity becomes discontinuous on the modon boundary. The flow inside of the modon boundary may have the same high-over-low dipole structure as the modon in uniform zonal flow. The outside flow rapidly approaches the sheared zonal background flow as receding from the modon boundary.