Planetary-scale MLT waves diagnosed through multi-station methods

Most experimental investigations on planetary-scale waves in the mesosphere lower thermosphere (MLT) region are based on single-station or -satellite spectral analysis methods, which are subject to intrinsic spectral aliasing/ambiguity. To conquer the aliasing, the author developed and implemented dual- and multi-station spectral methods in a series of recent works. These methods were implemented on meteor radar observations and surface magnetometer observations. A variety of waves were discovered or investigated in terms of seasonal variations and responses to sudden stratospheric warming events, including lunar and solar tides (migrating and non-migrating), Rossby wave normal modes, quasi-two-day waves, ultra-fast Kelvin waves, and secondary waves of wave-wave nonlinear interactions between the previous waves. The current paper uses synthetic data to illustrate the three methods and reviews comparatively these methods and results in plain language.