台风的螺旋结构

本文从描写台风运动的动力方程组出发,讨论了台风的螺旋结构,给出了这种螺旋结构的图样,指出:(1)台风螺旋结构的形成是台风中重力惯性内波,特别是重力内波的作用所致,(2)台风螺旋结构的形式与波位相速紧密相关,北半球的曳式螺旋结构要求螺旋图样环绕台风眼逆时针且由中心向外运动,其向外运动的速度近于重力内波的传播速度,(3)台风的曳式螺旋倾角一般小于45°,而在台风边缘,倾角约为10°,螺旋臂间距在二旋臂结构中平均为220公里,而在四旋臂结构中平均为110公里,(4)台风螺旋波也有频散作用,在曳式螺旋中c_(gr)与c_r皆为正,且c_(gr)

THE SPIRAL STRUCTURE OF THE TROPICAL CYCLONE

In this paper, starting from the equations describing tropical cyclone, the spiral structure of the tropical cyclone is discussed and the flow pattern is described. It shows that the formation of spiral structure is due to the action of internal gravity-inertia waves,particularly internal gravity waves. The spiral form is connected with the phase velocity of waves. The "trailing" spiral structure in the Northern Hemisphere demands that the spiral lines move counter-clockwise and outward. The angle with which a spiral line intersects with a circle of radius r is ordinarily less than 45°,at the edge of tropical cyclone it is about 10°.The distance between the spiral "arms" is about 220 km for m=2, 110 km for m=4.The spiral waves of the tropical cyclone are dispersive. In the "trailing" spiral, c_gr and c_r are always positive, and c_gr<c_r.It is found that, if the water vapor is enough and latent heat is more than enough,the tropical cyclone may mamtain.