Longitudinal peculiarities of planetary waves-zonal flow interactions and their role in stratosphere-troposphere dynamical coupling

Three-dimensional (3D) planetary wave analysis can provide more regionalized information on stratospheric-tropospheric dynamic interactions. The upward wave flux from the troposphere to the stratosphere is maximized above northeastern Eurasia, while the downward flux occurs mainly over the North America and North Atlantic (NANA) region, which is much stronger during mid-to-late winter. This distribution is determined by the wave-wave interactions between the different wavenumbers of planetary waves, especially between wavenumber 1 and wavenumber 2. The upward wave flux anomalies in early winter are negatively correlated with the strength of the stratospheric polar vortex (SPV). During the mid-to-late winter months, the strength of the SPV is positively correlated with the first mode of the 3D wave flux and has a leading relationship of approximately one month. The stronger SPV corresponds to a stronger upward wave flux above northern Eurasia and stronger downward flux over the NANA region. The interannual variations in wave flux during early winter are closely associated with the Scandinavian wave train pattern. In contrast, the wave flux variations are related to the circulation anomaly corresponding to the Arctic Oscillation during mid-to-late winter, which causes climate anomalies across the Northern Hemisphere, especially coherent temperature changes in northern Europe, eastern United States and northeastern China.