Upward and downward atmospheric Kelvin waves over the Indian Ocean
Upward and downward atmospheric Kelvin waves over the Indian Ocean
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印度洋上空的向上和向下大气开尔文波
DOI：
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发表时间：
2021
影响因子：
8.9
通讯作者：
P. Roundy
中科院分区：
文献类型：
--
作者：
A. A. Shaaban;P. Roundy
平流层Kelvin波通常被理解为平面重力波，而对流层Kelvin波被解释为斜压模态之间的叠加。傅立叶滤波用于将ECMWF-Interim再分析动力场分解为向上和向下传播分量。然后，小波回归被用来隔离传播的开尔文波在印度洋上跨越不同的速度在纬向波数4。快波的结果显示对流层中的干燥向上相位信号，而向下相位开尔文波占据了平流层的大部分。对流层中向上相位倾斜波的存在表明对流层开尔文波不是向上和向下分量的叠加，正如人们在正常模式中所期望的那样。我们发现，在对流层中传播的开尔文波服从重力波动力学与位势高度的相位与纬向风，垂直速度的相位与纬向风，和正交的纬向风的温度。干燥和潮湿的对流层开尔文波都表现出向西的垂直倾斜，这表明倾斜可能不是斜压模式与对流和层状加热耦合的叠加。在辐射重力波的背景下，结果表明，更快的对流层开尔文波似乎与更高的Brunt-Väisälä频率相关，并且波在很宽的相速度范围内保持类似的垂直倾斜。
Stratospheric Kelvin waves are often understood as plane gravity waves, yet tropospheric Kelvin waves have been interpreted as a superposition between the baroclinic modes. Fourier filtering is used to decompose the ECMWF‐Interim reanalysis dynamical fields into upward and downward propagating components. Then wavelet regression is used to isolate the propagating Kelvin waves over the Indian Ocean across different speeds at zonal wavenumber 4. Results for fast waves show dry upward‐phase signal in the troposphere, while downward‐phase Kelvin waves occupy most of the stratosphere. The presence of upward‐phase tilted waves in the troposphere suggests that the tropospheric Kelvin wave is not a superposition of the upward and downward components, as one might expect in a normal mode. We found that propagating Kelvin waves in the troposphere obey gravity wave dynamics with geopotential height in phase with the zonal wind, the vertical velocity out of phase with the zonal wind, and the temperature in quadrature with the zonal wind. Both dry and moist tropospheric Kelvin waves show a westward vertical tilt, suggesting that tilt probably cannot be a superposition between baroclinic modes coupled to convective and stratiform heating. In the context of radiating gravity waves, results suggest that faster tropospheric Kelvin waves appear to be associated with higher Brunt–Väisälä frequencies, and waves maintain similar vertical tilt across a wide range of phase speeds.
影响因子：
3.1
作者：
Yang G
通讯作者：
Yang G
影响因子：
8.9
作者：
P. Roundy
通讯作者：
P. Roundy
QBO 相反相位的赤道波
影响因子：
3.1
作者：
Yang G
通讯作者：
Yang G