Abstract
The movement of the cyclonic vortex is examined by some numerical experiments of barotropic models. It is confirmed that the northward acceleration of axially symmetric non-divergent vortex on a β-plane is proportional to the scale and the strength of the vortex, which was predicted by Rossby (1948). It is found that the accelerative motion is accompanied by the motion with a nearly constant northward speed. The speed is approximately represented by the relation Cy=0.52β0.6L01.2U00.4 in the range of BL02/U0<0.01, where β, L0 and U0 are the northward gradient of the Coriolis parameter, the characteristic size and intensity of the vortex, respectively.
The oscillatory motion on the vortex path is also found in our experiments. The period is in the range from 10 to 30 hours. However the dependence of the period on the size and intensity of the vortex is not necessarily in agreement with the theoretical result by Yeh (1950) and Kuo (1950).
