Equatorial Waves in Opposite QBO Phases
Equatorial Waves in Opposite QBO Phases
复制标题
QBO 相反相位的赤道波
DOI：
10.1175/2010jas3514.1
复制
发表时间：
2011
影响因子：
3.1
通讯作者：
Yang G
中科院分区：
文献类型：
--
作者：
Yang G
本文采用赤道波识别方法，分析了1992年和1993年ECMWF 40年多水平Re-Analysis （ERA-40）资料，探讨了赤道波在准两年振荡（QBO）相反相位下的行为。本文对赤道开尔文波、向西移动的混合罗斯比重力波（WMRG）和n= 1罗斯比（R1）波在QBO不同相的三维结构、纬向和垂直传播进行了全面的研究。与基于理论的预期一致，向上传播的开尔文波在QBO的东风期比在QBO的西风期更频繁地发生。而向西移动的WMRG和R1波表现出相反的行为。平流层中垂直传播的赤道波的存在也取决于对流层上层的风和对流层强迫。得到了典型的传播参数，如纬向波数、纬向相速度、周期、垂直波长和垂直群速度。一般来说，平流层下层的波比对流层上层的波纬向波数少，周期短，相速快，垂直波长短。平流层下层的波均表现为群速度向上，相速度向下。当QBO相位不利于波传播时，波在平流层下层的相速比有利相位时大，周期比有利相位时短，表明环境气流对慢波进行了多普勒频移和滤波。西半球对流层WMRG和R1波也表现为相速上升和群速下降，表明它们的强迫来自中纬度地区。虽然平流层下层观测到的波以“自由”波为主，但有证据表明，在暖水半球的开尔文波和西半球的WMRG和R1波的有利年份，它们与之前的热带对流有一定的联系，这表明对流强迫对传播耦合开尔文波的存在和中纬度强迫对耦合开尔文波的存在的重要性。
A methodology for identifying equatorial waves is used to analyze the multilevel 40-yr ECMWF Re-Analysis (ERA-40) data for two different years (1992 and 1993) to investigate the behavior of the equatorial waves under opposite phases of the quasi-biennial oscillation (QBO). A comprehensive view of 3D structures and of zonal and vertical propagation of equatorial Kelvin, westward-moving mixed Rossby–gravity (WMRG), andn= 1 Rossby (R1) waves in different QBO phases is presented. Consistent with expectation based on theory, upward-propagating Kelvin waves occur more frequently during the easterly QBO phase than during the westerly QBO phase. However, the westward-moving WMRG and R1 waves show the opposite behavior. The presence of vertically propagating equatorial waves in the stratosphere also depends on the upper tropospheric winds and tropospheric forcing.Typical propagation parameters such as the zonal wavenumber, zonal phase speed, period, vertical wavelength, and vertical group velocity are found. In general, waves in the lower stratosphere have a smaller zonal wavenumber, shorter period, faster phase speed, and shorter vertical wavelength than those in the upper troposphere. All of the waves in the lower stratosphere show an upward group velocity and downward phase speed. When the phase of the QBO is not favorable for waves to propagate, their phase speed in the lower stratosphere is larger and their period is shorter than in the favorable phase, suggesting Doppler shifting by the ambient flow and a filtering of the slow waves. Tropospheric WMRG and R1 waves in the Western Hemisphere also show upward phase speed and downward group velocity, with an indication of their forcing from middle latitudes. Although the waves observed in the lower stratosphere are dominated by “free” waves, there is evidence of some connection with previous tropical convection in the favorable year for the Kelvin waves in the warm water hemisphere and WMRG and R1 waves in the Western Hemisphere, which is suggestive of the importance of convective forcing for the existence of propagating coupled Kelvin waves and midlatitude forcing for the existence of coupled WMRG and R1 waves.
登录
查看更多内容
影响因子：
3.1
作者：
Yang G
通讯作者：
Yang G
使用 GROGRAT 射线追踪器研究赤道开尔文波平均分布的特性
DOI：
--
发表时间：
2009
期刊：
影响因子：
--
作者：
M. Ern;H. Cho;P. Preusse;S. Eckermann
通讯作者：
S. Eckermann
影响因子：
--
作者：
S. Alexander;T. Tsuda;Y. Kawatani;M. Takahashi
通讯作者：
S. Alexander;T. Tsuda;Y. Kawatani;M. Takahashi
DOI：
10.1029/2008jd010374
发表时间：
2009-01
期刊：
Journal of Geophysical Research: Atmospheres
影响因子：
--
作者：
Y. Kawatani;M. Takahashi;Kaoru Sato;S. Alexander;T. Tsuda
通讯作者：
Y. Kawatani;M. Takahashi;Kaoru Sato;S. Alexander;T. Tsuda
赤道开尔文波在大气环流模型中平流层-对流层交换中的作用
影响因子：
--
作者：
M. Fujiwara;M. Takahashi
通讯作者：
M. Takahashi