Soutenance de Tim Marino
| When |
Oct 07, 2026
from 02:00 to 04:00 |
|---|---|
| Where | Amphi Anne L'Huillier |
| Contact Name | Tim Marino |
| Attendees |
Tim Marino |
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While it is known that, in a changing climate, shifts and modulations of atmospheric patterns may have important effects on regional climate or extreme events, it is often assumed that the general structure of the circulation should not change. This thesis explores the possibility that the large-scale atmospheric circulation might, in fact, undergo a major reorganization in a different climate. A candidate for such a change is a phenomenon called equatorial superrotation, which consists of the presence of a maximum of angular momentum at the equator, and consequently of westerly winds in the troposphere, as opposed to the typical easterly winds at Earth's equator.
Superrotation has been broadly studied in the context of planetary atmospheres: several planets of the solar system, such as Venus or Jupiter, exhibit superrotation. In this context, several mechanisms have been proposed to explain a potential transition to a superrotating atmosphere. On the other hand, while it has been suggested that superrotation could also be relevant for warm climates of the past on Earth, the circumstances, dynamics and consequences of such a transition remain poorly understood.
The objective of this thesis is to try to answer some open questions on this topic: could superrotation be relevant for the Earth's atmosphere, and if so, what are the involved mechanisms and what impact would it have on the rest of the climate system? We investigate these questions in a variety of models of different complexities, using tools from geophysical fluid dynamics and climate modeling. More specifically, we study the dynamics of the transition to superrotation and its impacts on climate in a General Circulation Model. We then investigate a wave-mean flow interaction mechanism which could lead to an abrupt transition to superrotation in a simplified model.