论文标题
行星波和波浪的相移 - 潮汐锁定的行星上的射流共振
Phase Shift of Planetary Waves and Wave--Jet Resonance on Tidally Locked Planets
论文作者
论文摘要
最近的研究发现，潮汐锁定的行星上的大气超支（即，赤道的西风在赤道上）可以改变行星波的阶段。但是，没有检查超值激流与相移的大小之间的明显关系。在这项研究中，我们使用具有指定统一层流的二维（2D）线性浅水模型来重新调查此问题。我们发现相移的程度是平均流量强度的单调但非线性函数，并且相移的两个限制为-y $π$和 +$π$。可以使用整个系统的能量平衡来解释这些限制的存在。我们进一步表明，当向东射流的速度接近Rossby波的向西相位速度，或者开尔文波之间的共振和平均流程之间发生时，当向东的速度接近向西射流时，向西喷射的速度接近开尔文波的向东相位速度时，就会发生共振。共振机制与以前关于地球和热木星的研究相同。此外，在潮汐锁定的岩石行星的3D全球大气通用循环模拟的旋转期间，我们还发现了这两种现象：相位移位和波浪 - 喷射式共振。这项研究提高了对潮汐锁定行星的波浪流相互作用的理解。
Recent studies found that atmospheric superrotation (i.e., west-to-east winds over the equator) on tidally locked planets can modify the phase of planetary waves. But, a clear relationship between the superrotation and the magnitude of the phase shift was not examined. In this study, we re-investigate this problem using a two-dimensional (2D) linear shallow water model with a specified uniform zonal flow. We find that the degree of the phase shift is a monotonic but nonlinear function of the strength of the mean flow, and the phase shift has two limits of -$π$ and +$π$. The existence of these limits can be explained using the energy balance of the whole system. We further show that a resonance between the Rossby wave and the mean flow occurs when the speed of an eastward jet approaches to the westward phase speed of the Rossby wave, or a resonance between the Kelvin wave and the mean flow happens when the speed of a westward jet approaches to the eastward phase speed of the Kelvin wave. The resonance mechanism is the same as that found in the previous studies on Earth and hot Jupiters. Moreover, in the spin-up period of a 3D global atmospheric general circulation simulation for tidally locked rocky planet, we also find these two phenomena: phase shift and wave--jet resonance. This study improves the understanding of wave--mean flow interactions on tidally locked planets.
