Global distribution of atmospheric waves in the equatorial upper troposphere and lower stratosphere: AGCM simulation of sources and propagation
Global distribution of atmospheric waves in the equatorial upper troposphere and lower stratosphere: AGCM simulation of sources and propagation
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DOI：
10.1029/2008jd010374
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发表时间：
2009-01
期刊：
影响因子：
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通讯作者：
Y. Kawatani;M. Takahashi;Kaoru Sato;S. Alexander;T. Tsuda
中科院分区：
文献类型：
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作者：
Y. Kawatani;M. Takahashi;Kaoru Sato;S. Alexander;T. Tsuda
利用T106L60大气环流模式(120公里水平分辨率和550米垂直分辨率)研究了赤道对流层上层和平流层下层大气波的全球分布、来源和传播。在不设置重力波阻力参数的情况下，对∼周期为1.5~2年的准两年振荡进行了较好的模拟。纬向波数与模拟降水频谱的关系代表了对流耦合赤道陷波(EQW)的真实信号。平流层的温度谱也显示了EQW的主要信号。分别提取了从n=−1模到n=2模的等效深度在8-90m范围内的EQW。平流层中的每个EQW通常与对流层中每个对流耦合的EQW活动的来源很好地对应。Kelvin波和n=0向东/向西传播的EQW受Walker环流和QBO位相的强烈影响。与EQW相关的位能一般在西风比在QBO的东切变位相要大。在赤道上空20-30公里高度，垂直波长为≤7公里的EQW贡献了∼总势能≤的30%。由积云对流产生的周期为≤24 h的重力波在非洲、亚马逊和印度尼西亚周围地区清晰可见，并在距震源区较近的地区造成局部性的PE分布。讨论了模型结果与最新卫星观测结果的比较。
The global distribution, sources, and propagation of atmospheric waves in the equatorial upper troposphere and lower stratosphere were investigated using an atmospheric general circulation model with T106L60 resolution (120‐km horizontal and 550‐m vertical resolution). The quasibiennial oscillation (QBO) with a period of ∼1.5–2 years was simulated well without gravity wave drag parameterization. The zonal wave number versus the frequency spectra of simulated precipitation represent realistic signals of convectively coupled equatorial trapped waves (EQWs). The temperature spectra in the stratosphere also indicate dominant signals of EQWs. EQWs with equivalent depths in the range of 8–90 m from the n = −1 mode to n = 2 mode were extracted separately. Each EQW in the stratosphere generally corresponded well with the source of each convectively coupled EQW activity in the troposphere. The propagations of Kelvin waves and n = 0 eastward/westward propagating EQWs are strongly influenced by the Walker circulation and the phase of the QBO. Potential energy associated with EQWs is generally larger in the westerly than in the easterly shear phase of the QBO. EQWs with vertical wavelengths ≤ 7 km contribute up to ∼30% of total potential energy ≤ 7 km over the equator at an altitude of 20–30 km. Gravity waves generated by cumulus convection with periods ≤ 24 h are clearly visible over areas of Africa, the Amazon, and around Indonesia, and result in localized PE distributions in areas short distances from the source region. Comparisons of the model results and recent satellite observations are discussed.