Nonlinear motion of a shallow water barotropic vortex Article

Willoughby, HE. (1994). Nonlinear motion of a shallow water barotropic vortex . JOURNAL OF THE ATMOSPHERIC SCIENCES, 51(24), 3722-3744. 10.1175/1520-0469(1994)051<3722:NMOASW>2.0.CO;2

cited authors

  • Willoughby, HE

authors

abstract

  • Nonlinear motions of a shallow water barotropic vortex on a β plane differ substantially from the analogous linear motions. The nonlinear model described here, in which wavenumber 1-3 asymmetries interact with each other and the mean vortex, predicts that an initially completely cyclonic vortex will accelerate toward the NNW reaching a speed of 2.5 m s-1 at 48 h. During the test of the 240-h calculation, the speed varies by <0.5 m s-1 as the direction turns from NNW to NW. The vortex accelerations are in phase with temporal changes of vortex-relative angular momentum (LR). The turning of the track coincides with a transition of the wavenumber 1 asymmetry from a single dipole to a double dipole. The latter structure appears to be another orthogonal solution of the second-order radial structure equation for a neutral linear normal mode. -from Author

publication date

  • January 1, 1994

published in

start page

  • 3722

end page

  • 3744

volume

  • 51

issue

  • 24