余志豪. 2002. 台风螺旋雨带——涡旋Rossby波[J]. 气象学报, 60(4):502-507, doi:10.11676/qxxb2002.059
台风螺旋雨带——涡旋Rossby波
THE SPIRAL RAIN BANDS OF TROPICAL CYCLONE AND VORTEX ROSSBY WAVES
投稿时间:2002-04-20  修订日期:2002-08-10
DOI:10.11676/qxxb2002.059
中文关键词:  台风  螺旋云雨带  涡旋Rossby波
英文关键词:Tropical cyclone  Spiral rain band  Vortex Rossby wave
基金项目:
作者单位
余志豪 南京大学大气科学系, 南京, 210093 
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中文摘要:
      台风中的螺旋云雨带是由多种探测手段被观测到的现象,是为大家所共识的不争事实.但是,对它的形成、维持的理论解释,虽有多种学说,一直以来人们都倾向于重力惯性波说.而重力惯性波说有一个致命的弱点,即波的相速理论值为101m/s量级,它要比螺旋云雨带实测移速只有100m/s几乎大一个量级.于是从前几年开始,人们又回到30多年前提出的涡旋Rossby波说那里去寻找合适的解释.经典的Rossby波是β=(df/dy)作用的大尺度波动,而适用于台风中螺旋云雨带的涡旋——Rossby波乃是f平面(β=0)上的中尺度波动.那末,对这两类尺度不同和成波机理不同的波动,何以均冠予Rossby波一词?本文试图从动力学等价原理上,对此作统一联系的说明.其结果是:台风基本气流的涡度ζ随径向(r)变化的梯度dζ/dr=(1/r)(∂/∂r)(rvλ),在动力学上等价于科氏参数f随纬度变化的梯度即β=df/dy;或者说它们在绝对涡度守恒的前提下,作为波扰动的成波机理是等价的.
英文摘要:
      The spiral rain bands of tropical cyclone and the vortex Rossby waves are reviewed.It is pointed specially that the axisymmetrizing disturbances on a vort exare accompanied by out ward-propagating vortex Rossby waves whose restoring mechanism is associated with the gradient of storm vorticity,for the goal of elucidating the dynamics of outward-propagating spiral bands in tropical cyclone.The theoritical value of its outward-propagating speed is about O(10 m/s),almost to be consistent with observational one of spiral rain bands.Based on the principle of conservation of vorticity(or PV),the restoring mechanism of vortex Rossby wave is equivalent dynamically to the planetary Rossby wave.
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