Circulation changes are at the heart of changes in both regional precipitation and temperature and extreme events ranging from heavy precipitation to heat waves or cold spells. Understanding and modelling circulation changes in a warming climate therefore constitutes an emerging challenge for climate science. General circulation models still struggle to represent important features of the large-scale circulation in the present-day climate, which undermines confidence in future projections.
The present project is to combine a small-scale process-level with a large-scale dynamical perspective to investigate how drag processes at the Earth's surface associated with boundary-layer turbulence, orography and gravity waves affect large-scale circulation. Our aim is to develop a climatological view of the distribution and variability of individual components of surface drag as represented in general circulation models and to understand which processes or model parametrisations are responsible for current model biases especially in the representation of mid-latitude storm tracks.