Prof. Huixin Liu (Kyushu University, Japan) will deliver a talk on the topic, "Tidal variation in the MLT region due to El-Nino Southern Oscillation" at IAP colloquium on 19th Dec 2022.

She will discuss the El-Nino Southern Oscillation (ENSO) as a recurrent climate phenomenon caused by complex ocean-atmosphere interaction in the tropical Pacific ocean. ENSO affects not only troposphere climate and weather patterns, but also the stratosphere and beyond. In this talk, she will present ENSO effects on atmospheric tide, which plays a pivotal role in dynamically linking the lower and upper atmosphere and the ionosphere. In particular, she will focus on the record-strong 2015 El-Nino event. This event produced large enhancement (over 70%) in the diurnal tidal component DW1 observed by both Ground-based and satellite observations. They explore the mechanisms for the enhancement using whole atmosphere model GAIA, and quantify the relative role of tidal heating and background wind. In addition, they also examine the role of ENSO-induced ozone modulation in affecting the tides. These results demonstrate the strong vertical coupling processes between different atmosphere layers and the need for their systematic treatment as a whole.