Forcing mechanisms of the migrating quarterdiurnal tide
Forcing mechanisms of the migrating quarterdiurnal tide
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DOI：
10.5194/angeo-38-527-2020
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发表时间：
2020-04
影响因子：
1.9
通讯作者：
Christoph Geißler;C. Jacobi;F. Lilienthal
中科院分区：
文献类型：
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作者：
Christoph Geißler;C. Jacobi;F. Lilienthal
抽象的。我们使用非线性机制全球环流模型来分析中层大气中迁移的四分之一日潮汐（QDT），重点关注其可能的强迫机制：臭氧和水蒸气吸收太阳辐射、非线性潮汐相互作用以及重力波-潮汐相互作用。我们展示了 QDT 振幅的气候学，并研究了不同强迫机制对 QDT 振幅的贡献。为此，我们首先从模型趋势项中提取QDT，然后从不同趋势项中去除各自的QDT贡献。我们发现太阳强迫机制对于QDT来说是最重要的机制；然而，非线性和重力波强迫机制也在秋季和冬季发挥作用，特别是在中低纬度的中间层和低热层。此外，还观察到各个强迫机制之间的破坏性干扰。因此，在消除非线性或重力波强迫机制的模拟中，潮汐幅度变得更大。
Abstract. We used a nonlinear mechanistic global circulation model to analyze the migrating quarterdiurnal tide (QDT) in the middle atmosphere with focus on its possible forcing mechanisms: the absorption of solar radiation by ozone and water vapor, nonlinear tidal interactions, and gravity wave–tide interactions. We show a climatology of the QDT amplitudes, and we examine the contribution of the different forcing mechanisms to the QDT amplitude. To this end, we first extracted the QDT from the model tendency terms and then removed the respective QDT contribution from the different tendency terms. We find that the solar forcing mechanism is the most important one for the QDT; however, the nonlinear and gravity wave forcing mechanisms also play a role in autumn and winter, particularly at lower and middle latitudes in the mesosphere and lower thermosphere. Furthermore, destructive interference between the individual forcing mechanisms is observed. Therefore, tidal amplitudes become even larger in simulations with the nonlinear or gravity wave forcing mechanisms removed.