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一、引 言 Ooyama(1982)论述了一个热带气旋的数值模式应该包括中尺度对流系统的动力学,它比以往只考虑热力学可能更明确。Lord等人(1984)最近的文章进一步指出:甚至在微物理学中的冰相也不可忽视它在中尺度输送中的作用。在谱模式的另一方面,三维天气的环境对涡旋运动的预报和气旋生成问题也是必不可少的。作为我们对飓风动力学和预报有计划研究的第一步,正在研究一个嵌套多重定义域上的谱预报模式,它包含了所有重要的尺度。尽管完备的模式还有待于完成,但谱嵌套方法已证实了:在一维和二维试验中,它明显地优于格点有限差分的任何已知嵌套方法。 本文中对谱嵌套原则进行评述,并讨论一个平动的飓风对摩擦边界层中二维非对称流的应用。1982年Debby飓风的雷达回波与根据模式计算辐合场二者之间的极端一致,令人满意地证实了,在一个飓风的内区中需要高的分辨率。这种一致也进一步表明:涡旋和环境流场之间通过边界层的非线性气流而产生的运动学相互作用的重要性。
I. INTRODUCTION Ooyama (1982) discusses that the numerical model of a tropical cyclone should include the dynamics of mesoscale convective systems, which may be more explicit than in the past only considering thermodynamics. A recent article by Lord et al. (1984) further states that even the ice phase in microphysics can not neglect its role in mesoscale transport. On the other hand, the three-dimensional weather environment is also essential for the prediction of vorticity and the problem of cyclone formation. As a first step toward our planned study of hurricane dynamics and forecasting, we are studying a model for the prediction of spectra over a nested multiple domain that covers all the important dimensions. Although complete patterns have yet to be completed, the spectral nesting approach has demonstrated that it is significantly superior to any known nesting method for the finite difference of the lattice in one- and two-dimensional experiments. This paper reviews the principle of spectral nesting and discusses the application of a translational hurricane to two-dimensional asymmetric flow in the friction boundary layer. The extreme agreement between the radar echoes of Hurricane Debby in 1982 and the convergence of modes calculated according to the model satisfactorily confirms the high resolution required in the inner region of a hurricane. This agreement is further evidence of the importance of the kinematic interactions created by the non-linear airflow over the boundary layer between the vortex and the ambient flow field.