NUMERICAL SIMULATION OF TROPICAL CYCLONE MOVEMENT WITH THE RELATED CRITICAL POINT PHENOMENON^*

A study is made of the paths of tropical cyclones under the joint action of environmental flow and heating fields in terms of a quasi-geostrophic barotropic model with the thermal forcing and dissipation terms involved,in which 16 experiments are designed and integrated for more than 7 model days.Results show that for different parameter values of the environmental flow and heating field,and the cyclone scale,such paths as counterclockwise looping,zigzag form and westward march with an abrupt turning towards the north are reproduced clearly in the model atmosphere,exhibiting their critical points of nonlinear character.