台风环流区域内中尺度涡量传播特征的研究

A STUDY ON MESOSCALE VORTICITY PROPAGATIONS IN A TYPHOON-LIKE VORTEX

中文关键词:  中尺度涡旋  台风  涡旋对  强度变化

英文关键词:Mesoscale vortex  Typhoon  Pair of smaller scale vortices  Intensity changes

中文摘要:

      用一个高分辨率f平面直角坐标系的正压准地转模式,实施了10组积分时间为36h的试验,研究了初始位于台风外区的一个中尺度涡旋与台风涡旋的相互作用.结果表明:这种相互作用可以激发一个从外区伸展到内区的较小尺度的涡旋对,以此方式将涡量内传至台风中心附近.同时,中尺度涡旋呈现涡量集中化的特征.涡量内传与涡量集中化共存,使内区涡量增多,导致台风增强.此外,在一定条件下,这种相互作用还可以使涡量带破碎和断裂,形成一系列空间尺度更小的涡块.

英文摘要:

      By using an f-plane barotropic quasigeopotential model in the rectangular coordinate with the grid space of 5 km,ten experiments whose integration times are 36 hours are performed in order to study the interaction between a mesoscale vortex and a typhoon vortex,the initial position of the center of the mesoscale vortex is located in northwest direction to the typhoon center,with the distance between two centers being 2 r_m,where r_m is the radius of maximum wind of the typhoon vortex.Results show that the interaction can crest a pair of smaller scale vortices or lumps,which extend from the outside region of the typhoon to near its center,resulting in the mesoscale vortcity propagation into the inside region.In this process,the vorticity concentration of the mesoscale vortex may appear.The coexistence of the propagation and the concentration makes the increase of vorticity in the inside region and more intensive typhoon.Meanwhile,the intensity of the lump with positive vorticity changes with time,with the oscillation period being several hours,the change of distance from the typhoon center to the lump center has a similar oscillation period,which reduces the oscillation of typhoon intensity.In the case of stronger circular basic current,the interaction can make the intensification of typhoon more obviously.In addition,in some parametric conditions,the interaction may break down the continuous vorticity zone,exhibiting a cluster of smaller vorticity lumps.