We use a 3-D general circulation model, the UK Met Office’s Unified Model, to study the atmospheric dynamics of tidally locked exoplanets. These planets, which are thought to be common in the universe, orbit closely enough to their host stars to develop synchronous rotation, so that one hemisphere is always facing the star. The contrast between a highly irradiated dayside and a dark nightside leads to a characteristic circulation pattern not found in the solar system. Even though tidally locked planets lack daily, seasonal, or annual variations in stellar radiation, these planets still develop intrinsic atmospheric variability because of the effects of atmospheric waves, including Rossby, Kelvin, and gravity waves. In this seminar, I will discuss oscillations in stratospheric jets (analogous to the Earth’s quasi-biennial oscillation), travelling cyclonic structures, and impacts on the abundances of atmospheric species observable by telescopes.

Maureen Cohen, 2nd year PhD candidate, University of Edinburgh, School of GeoSciences. Supervisors: Dr Massimo Bollasina, Professor Paul Palmer, Professor Giovanna Tinetti