Records Analysis in Climate Attribution

Résumé

Numerical climate models are complex and combine a large number of physical processes. They are key tools in quantifying the relative contribution of potential anthropogenic causes (e.g., the current increase in greenhouse gases) on high-impact atmospheric variables like heavy rainfall or temperatures. These so-called climate extreme event attribution problems are particularly challenging in a multivariate context, that is, when the atmospheric variables are measured on a possibly high-dimensional grid. In addition, global climate models like any in sillico numerical experiments are affected by different types of bias. In this talk, I will discuss about how to combine to two statistical theories to assess causality in the context of extreme event attribution. In addition, the question of uncertainties quantification that remains a challenge in any climate attribution analysis will be explored from various directions. In particular, a simple model bias correction step for records will described in details. To illustrate our approach, we infer emergence times in precipitation from the CMIP5 and CMIP6 archives.

This is joint work with Anna Kiriliouk, Paula Gonzalez Soulivanh Thao and Julien Worms.

Biographie

Philippe Naveau est chercheur scientifique senior au Laboratoire des Sciences du Climat et de l’Environnement du CNRS à Gif-sur-Yvette (Saclay, France). Il travaille notamment sur la détection et l’attribution d’événements extrêmes. Phillipe a obtenu un doctorat en statistique de Colorado State University en 1998 sous la direction de R. Tweedie et R. Davis et a travaillé à University of Boulder et NCAR avant de rejoindre le CNRS.