Steady motion and spiral patterns in typhoon

By using the equations describing typhoons in the atmosphere,the steady three-dimensional stream field and the corresponding pressure and temperature fields are obtained. The three-dimensional velocity fields construct a nonlinear autonanous system in the physical space.It is shown that the center of typhoon is a local minimum pressure with positive vertical vorticity and horizontal convergence in lower levels and a local marumum pressure with negative vertical vorticity and horizontal divergence in the upper levels. Because there exist two saddle-focus points in the autonornous system,there exist the spiral patterns,in which the winds blow spinally in and out of the center in the lower and upper levels in the Northern Hanisphere and cause the ascending rrotion near the center and descending motion and the edge,respectively.All these are in fair oonfoxmity with the observations.It impVes that the rotation of earth and the visooaity of air play an important role in the spiral structure of typtxbns.