| Parametrizing Convection across model scales: CoMorph and the ParaChute programme
Dr Alison Stirling – Met Office General circulation models contain approximations called parametrizations to represent the physical processes that occur on scales too fine to be resolved by the model grid. Parametrizing convection has been a particularly challenging task because of its multi-scale influence, and so systematic errors have persisted for decades. A prevailing view is to take advantage of new computing capability to move models towards km-scale resolutions, and thereby side-step the troublesome role of convection parametrisations. In this talk I will present our journey towards a flexible new convection parametrization scheme called CoMorph, which has produced better coupling between convection and the large-scale dynamics than previous schemes, and has shown promise in representing the diurnal cycle of convection over land. I will then give an overview of the ParaChute programme – a collaborative endeavour between NERC and the Met Office to improve the representation of turbulent (and convective) processes at km and sub-km scales, and the path for new representations of convection at these scales. |