Tropical cyclones generated by tropical transition over the North Atlantic Ocean and their potential hazards for Europe

During the last 15-years, the eastern North Atlantic has witnessed anomalous tropical cyclones (TCs) generated by the tropical transition (TT) process, some of them affecting or threatening European regions, causing societal damage and public concern.

TT is a recently detected TC formation process by which a baroclinically formed extratropical cyclone evolves into a system with a full TC structure. It is also this type of TCs that has the highest likelihood of affecting Europe because they form in midlatitudes.

Understanding the TT phenomenon is thus important for weather forecast and informing the public, and researching its link with anthropogenic climate change (ACC) could aid in future mitigation strategy, both with socioeconomical benefits.

Recent studies indicated a potential increase of ex-TCs affecting Europe, i.e. of TCs forming via the typical non-TT mechanism and transitioning into extratropical cyclones. However, these studies did not address the TT pathway. Considering the TT process provides a more reliable assessment of the risk of TCs affecting Europe.

In addition, newly developed high-resolution global climate models (GCMs) are now potentially capable of simulating TTs.

Thus, in order to fill the important knowledge gap about TCs affecting Europe, this project aims to (1) better characterize the development of TTs over the North Atlantic, their predictability and their relationship with midlatitude dynamics, (2) study the representation of TTs in state-of-the-art GCMs, and finally (3) assess the relationship between ACC and TTs, with special focus on Europe.

This project is original as it uses new tools and simulations and deals with specific aspects of North Atlantic TCs that have not been addressed before.

These aspects are likely highly important for providing the best possible service to society related to weather and climate predictions.