Effect of Semidiurnal Lunar Tides Modulated by Quasi‐2‐Day Wave on Equatorial Electrojet During Three Sudden Stratospheric Warming Events

Abstract

AbstractWe present an analysis of perturbations and wave characteristics in equatorial electrojet (EEJ) and equatorial zonal winds in the mesosphere and lower thermosphere region during three sudden stratospheric warming (SSW) events, based on the wind observations by two meteor radars in Indonesia and geomagnetic field observations in India. During three SSWs, remarkable semidiurnal perturbations occurred in the EEJ, accompanied by the strong 2‐day periodic perturbations simultaneously. The semidiurnal lunar (L2) tidal amplitudes in the EEJ and zonal winds showed the prominent enhancements during the episodes of EEJ perturbations. The time‐period power spectra of L2 tidal amplitudes in both the EEJ and zonal winds presented the obvious and coincident quasi‐2‐day wave (QTDW) enhancements during these periods. Our results first reveal the important contribution of QTDW to the distinctive EEJ perturbations during SSWs, and the semidiurnal lunar tides modulated by QTDW serve as the main forcing agent therein.