Representation of Mean Precipitation and Decadal Variability in Atmosphere Models

In this thesis, I investigated how decadal sea surface temperature variability affects precipitation over Europe and the Sahel using the atmosphere model OpenIFS. I found that European extreme precipitation is better represented at higher horizontal resolution, while the model time step has a limited effect on total precipitation extremes. For European winter precipitation, internal atmospheric variability dominates the variability, whereas SST forcing plays a relatively minor role. In contrast, Sahel summer precipitation responds strongly to AMV and IPV, with AMV mainly affecting the western Sahel and IPV mainly influencing the eastern Sahel.