The Importance of the Nontraditional Coriolis Terms in Large-Scale Motions in the Tropics Forced by Prescribed Cumulus Heating
The Importance of the Nontraditional Coriolis Terms in Large-Scale Motions in the Tropics Forced by Prescribed Cumulus Heating
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DOI：
10.1175/jas-d-11-0334.1
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发表时间：
2012-09
影响因子：
3.1
通讯作者：
Michiya Hayashi;Hisanori Itoh
中科院分区：
文献类型：
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作者：
Michiya Hayashi;Hisanori Itoh
在气象动力学中，动量方程一般采用浅层大气近似，同时采用“传统近似”。在传统的近似中，省略了两个余弦科里奥利项（以下称为非传统科里奥利项（NCT））和一些度量项。然而，一些研究表明，省略NCT可能不适合赤道附近的条件。因此，本文利用赤道β平面上线性化的准静力方程组，研究了NCT对模拟积云对流的局地正加热强迫下的大尺度运动的影响。假定规定加热以季节内的慢相速度向东移动。尺度分析和数值计算的结果表明，有和没有NCT的差异（以下简称贡献）表现出以下四个特点。(i)而对水平辐散和垂直速度的贡献较小。
AbstractIn meteorological dynamics, the shallow-atmosphere approximation is generally used in the momentum equation, together with the “traditional approximation.” In the traditional approximation, two cosine Coriolis terms [hereafter called nontraditional Coriolis terms (NCTs)] and some metric terms are omitted. However, some studies have suggested that the omission of the NCTs may not be appropriate for conditions near the equator. Therefore, this paper investigates the effect of the NCTs on large-scale motions forced by local positive-only heating mimicking cumulus convection.The authors use the linearized quasihydrostatic equation system on an equatorial β plane. Prescribed heating is assumed to move eastward with the slow phase speed of an intraseasonal period. Results of scale analysis and numerical calculations show that differences with and without the NCTs (hereafter, contributions) exhibit the following four features. (i) Whereas contributions to horizontal divergence and vertical velocity are s...