Scale Analysis for Large-Scale Tropical Atmospheric Dynamics
Scale Analysis for Large-Scale Tropical Atmospheric Dynamics
复制标题
大尺度热带大气动力学的尺度分析
DOI：
--
复制
发表时间：
2009
期刊：
影响因子：
--
通讯作者：
M. Bonazzola
中科院分区：
文献类型：
--
作者：
J. Yano;M. Bonazzola
摘要 对热带地区的大尺度动力学进行了系统尺度分析。研究发现，两种状态是相互竞争的：1）以热力学方程中垂直平流项和非绝热加热之间的平衡为特征的动力学，在给定速度尺度 U ∼ 10 m s−1 的情况下，在小于 L ∼ 103 km 的水平尺度上实现；2）由对流非绝热加热调制的线性赤道波动力学，在给定 U ∼ 3 m 的情况下，在大于 L ∼ 3 × 103 km 的尺度上实现s−1。在第一个动态状态（平衡）下，系统可以近似为渐近展开中不发散的领先顺序，正如查尼最初指出的那样。强调了热带大气大尺度尺度分析的内在微妙性。微妙之处主要源于无量纲 β 参数对水平尺度的强烈敏感性。正如上面所总结的，这相当于尺度仅相差 3 倍的定性不同的动态机制。因为任何...
Abstract A systematic scale analysis is performed for large-scale dynamics over the tropics. It is identified that two regimes are competing: 1) a dynamics characterized by balance between the vertical advection term and diabatic heating in the thermodynamic equation, realized at horizontal scales less than L ∼ 103 km given a velocity scale U ∼ 10 m s−1, and 2) a linear equatorial wave dynamics modulated by convective diabatic heating, realized at scales larger than L ∼ 3 × 103 km given U ∼ 3 m s−1. Under the first dynamic regime (balanced), the system may be approximated as nondivergent to leading order in asymptotic expansion, as originally pointed out by Charney. Inherent subtleties of scale analysis at large scales for the tropical atmosphere are emphasized. The subtleties chiefly arise from a strong sensitivity of the nondimensional β parameter to the horizontal scale. This amounts to qualitatively different dynamic regimes for scales differing only by a factor of 3, as summarized above. Because any ...