Comparative study of vertical motions in the global atmosphere evaluated by various kinematic schemes
Comparative study of vertical motions in the global atmosphere evaluated by various kinematic schemes
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通过各种运动学方案评估的全球大气垂直运动的比较研究
DOI：
10.2151/jmsj1965.78.3_289
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
A. Yatagai
中科院分区：
文献类型：
--
作者：
Hiroshi L. Tanaka;A. Yatagai
用各种经典的运动学方法估算的大尺度垂直运动与NCEP-NCAR和ECMWF再分析的结果进行了比较。经典的运动学方法包括中心差分法、平面拟合法和谱法。此外，本文还提出了一种简正波法，作为计算垂直运动的新方法。在该方法中，通过滤除高阶重力模式来控制错误的高频发散，而保留低频Rossby模式。结果表明，ECMWF再分析包含大量的小尺度涡旋，而NCEP-NCAR再分析则较为平滑，反映了不同的谱截断。正态模型法给出了垂直运动的合理分布，解决了谱法在复杂地形上的问题。结果表明，正态模方法对大气环流的诊断研究是有用的。
Large-scale vertical motions estimated by various classical kinematic methods are compared with those of NCEP-NCAR and ECMWF reanalyses. The classical kinematic methods include the central difference method, plane fitting method, and spectral method. In addition, a normal mode method is proposed in this study as a new approach to the computation of the vertical motion. In this method, the erroneous high frequency divergence is controlled by filtering the higher order gravity modes while the low-frequency Rossby modes are retained. According to the result, ECMWF reanalysis contains large amount of small-scale eddies, whereas the NCEP-NCAR reanalysis is smoother, reflecting the different spectral truncations. The normal model method provides a reasonable distribution of vertical motion, and the problem in the spectral method over the complex terrain is solved by this method. It is demonstrated that the normal mode method may be useful for the diagnostic studies of the general circulation of the atmosphere.