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Abstract:

In these 14 years as a climate researcher, a great part of my activity has been focused on the study of the North Atlantic-Europe climate variability and predictability from interannual to decadal timescales. The key objective is to understand the internal climate variability and how it can be modified in response to external forcings, as the anthropogenic emissions. In the North Atlantic, the large-scale atmospheric circulation, described in terms of weather regimes, can explain a great part of the local climate variability, since it modulates the temperature, precipitation and the storm-tracks intensity and pathways. I show here that weather regimes also allow the understanding of remote climate processes as tropical-extratropical teleconnections. Nevertheless in the midlatitudes areas climate signals are not easily detectable due to a large presence of chaotic variability.

A large body of my research has been also oriented to the evaluation of climate models (regional and global). Understanding the source of errors is crucial since most of our science relies on numerical modeling. I present a hierarchy of diagnostics, from an apparently simple analysis of the mean state bias, to the representation of the climate variability and more sophisticated process-based studies as the analysis of bias adjustment in seasonal and decadal forecasts.

Finally, I propose several perspectives aimed at i) improving our understanding of climate processes involving air-sea interactions and their influence of the large-scale atmospheric circulation over the midlatitude regions, and ii) reducing the uncertainty from climate models by proposing some alternatives to improve them.

Jury:

Prof. Olivier THUAL Correspondant
Prof. Francisco DOBLAS-REYES Rapporteur
Dr. Boris DEWITTE Rapporteur
Dr. Laurent Li Rapporteur
Prof. Noel Keenlyside Examinateur
Prof. Belen Rodriguez-Fonseca Examinateur