[A-CG33] Multi-scale ocean-atmosphere interaction in the tropics

[ACG33-P03] Atmospheric gravity wave activities during the 2015–2016 strong El Niño and anomalous QBO event

*Shih-Sian Yang¹, Chen-Jeih Pan¹ (1.National Central University, Taiwan)

Keywords:Atmospheric gravity waves, Quasi-biennial oscillation, El Niño and La Niña, ERA5 reanalysis data

Convection is one of the main sources of atmospheric gravity waves (AGWs). Tropospheric AGWs excited over the warm equatorial oceans can propagate upward into the stratosphere. However, the stratospheric zonal wind decides whether the waves can further propagate upward or not through wave-mean flow interactions. Also, AGWs play a crucial role in the evolution of the quasi-biennial oscillation (QBO) of the stratospheric zonal wind. A strong El Niño event occurred during 2015–2016. In the meanwhile, the evolution of stratospheric QBO was found to be anomalous. This study presents the AGW activities during 2015–2016. It is found that the AGW activity was significantly enhanced in the stratosphere and lower mesosphere during the strong El Niño and anomalous QBO event. However, the influence on the ionospheric total electron content was obscure. A further discussion is made in the present study to explain the mechanism that causes the variations of AGWs as seen during the 2015–2016 strong El Niño and anomalous QBO event.