Tropical cyclone scale vortices and associated Rossby waves were investigated numerically using high-resolution barotropic models on the global domain. The equations of the barotropic model were discretized using the spectral transform method with the spherical harmonics function as orthogonal basis. The initial condition of the vortex was specified as an axisymmetric flow in the gradient wind balance, and four types of basic zonal states were employed. Vortex tracks showed similar patterns as those on the beta-plane but exhibited more eastward displacement as they moved northward. The zonal-mean flow appeared to control not only the west-east translation but also the meridional translation of the vortex. Such a meridional influence was revealed to be associated with the beta gyre and the Rossby wave, which are formed around the vortex due to the beta effect. In the case of the basic zonal state of climatological mean, the meridional translation speed reached the maximum value when the vortex underwent recurving.

Abstract
Introduction
Barotropic Models on the Sphere and Initial Conditions
Results of Simulations
    Track of the vortices
    Rossby wave field and beta gyre
Summary and Conclusions
References

• Ye-Jin Nam(Department of Environmental Atmospheric Sciences, Pukyong National University)
• Hyeong-Bin Cheong(Department of Environmental Atmospheric Sciences, Pukyong National University) Corresponding author