罗哲贤. 1995. 大尺度涡旋的正压不稳定[J]. 气象学报, 53(3):281-288, doi:10.11676/qxxb1995.033
大尺度涡旋的正压不稳定
BAROTROPICAL INSTABILITY OF DISTURBANCES ON A LARGE CIRCLE VORTEX
投稿时间:1993-05-13  修订日期:1994-02-01
DOI:10.11676/qxxb1995.033
中文关键词:  正压不稳定  大尺度涡旋  圆形基流  数值试验
英文关键词:Barotropical instability  Large scale vortex  Circle parallel current  Numerical experiment
基金项目:国家自然科学基金
作者单位
罗哲贤 南京气象学院, 南京, 210044 
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中文摘要:
      用极坐标中线性化的正压涡度方程,将大尺度圆形基流上扰动的稳定性问题化为广义特征值的问题,得到了扰动振幅增长率沿方位角方向波数的关系。然后以不稳定模态的扰动流函数场作为初始场,在强、弱两类圆形基流的条件下,用直角坐标中准地转正压模式,分别实施积分时间为60h的试验。结果在模式大气中,初始扰动均随时间而增幅;强圆形基流的扰动增幅更快,并形成与台风螺旋云系看似有些相近的结构。
英文摘要:
      The barotropical instability for smaller scale disturbances superimposed on a large scale circle parallel vortex is investigated numerically.The growth rates of the orders of (10-4-10-5)s-1 are found at azimuthal wave numbers between 3.0 and 10.0.Then the most unstable mode for the disturbances is taken as the initial steamfunction field of a quasigeostrophic barotropical model and two numerical experiments whose integration times equal to sixty model hours are performed for more and less intense vortex, respectively.Results show that the initial small disturbances for the both all develop certainly and that vortex filaments exhibit in the edge of more intense vortex, which is somewhat similar to the observational phenomenon concering the outer structure of tropical cyclone.
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