Séminaire
The amplification of extreme rainfall rates with warming remains a key uncertainty associated with anthropogenic climate change. Simulations of precipitation extremes in current coarse-resolution global climate models are unreliable. Therefore, progress on the problem of changing precipitation extremes with warming must rely on either theory, observations, or simulations that resolve the convective-scale processes.
In this project, we investigate how precipitation extremes respond to an increase in temperature in high-resolution simulations that resolve the convective-scale processes. We start with idealized simulations in homogeneous settings, and introduce a scaling to investigate the behavior of precipitation extremes, and how it relates to the behavior of thermodynamic and dynamic variables. We then allow convection to organize in space, and examine the impact of convective organization on our results. Organized convection, for instance squall lines or tropical cyclones, is ubiquitous in the tropics and can cause severe damage. Finally, we compare theoretical expectations to the observed scaling between precipitation extremes and temperature, using data from HyMeX/MEDCORDEX simulations and surface weather stations in Southern France.