The Impact of the Quasi-Biennial Oscillation on the Mesosphere and Ionosphere

We studied the responses of the mesosphere and ionosphere to the quasi-biennial oscillation (QBO) in the stratosphere using meteor radar zonal wind observations over monitoring station Kototabang (KB, 0.2 degrees S, 100.3 degrees E), global zonal wind data from the thermosphere and ionosphere extension of the Whole Atmosphere Community Climate Model (WACCM-X), equatorial electrojet (EEJ) data over the monitoring station Jicamarca (12 degrees S, 77 degrees W) and global total electron content (TEC) maps. The Fourier fitting method was applied to obtain the monthly mean amplitudes of zonal wind, TEC and EEJ. The least squares fitting method was utilized to perform a spectral analysis. Our data indicate that the QBOs of the stratosphere and mesosphere are present in the zonal winds between 20 and 40 km and 82 and 96 km at KB. The QBO is also present in the global TEC at 40 degrees S to 40 degrees N latitude and is characterized by the equatorial ionization anomaly (EIA). We propose that the QBOs in the mesosphere are linked to the QBOs in the ionosphere through the modulation of the E region dynamo by neutral winds and the equatorial ionospheric fountain effect. This model is verified by the QBO signals in the EEJ and diurnal tides in the E region of the ionosphere. The absence of QBO signals in the zonal wind at 250 km confirms that QBO signals in the TEC are not modulated by the zonal wind in the F region ionosphere, which further substantiates the model.

Automated summary

This study reveals the responses of the mesosphere and ionosphere to the quasi-biennial oscillation in the stratosphere by analyzing observational data, and proposes a linkage between the QBO in the mesosphere and the QBO in the ionosphere.