Detailed microphysics in a Lagrangian cloud model
Lead Academic SupervisorAlan Blyth (School of Earth and Environment)
Lead Industrial SupervisorPaul Field, Met Office
Co-Supervisor(s)Onno Bokhove (School of Mathematics), Steven Böing (School of Earth and Environment) andDavid Dritschel (University of St Andrews)
The turbulent behaviour of clouds is responsible for many of the uncertainties regarding the timing and intensity of precipitation in weather and climate models. One of the fundamental problems here is that microphysical processes are essentially Lagrangian: they happen along trajectories of the flow (for small particles) or fall trajectories We have recently developed a new method, MPIC (Moist Parcel-In-Cell), which deals with the dynamics of clouds in an essentially Lagrangian framework, i.e. by advecting parcels of fluid. Here, we propose to use the MPIC method for studies of realistic atmospheric clouds and to couple the model to a bin microphysics scheme, where the amount of liquid water associated with drops of different size categories is prognosed. This bin microphysics approach has previously been successfully implemented in the Met Office LEM, but is computationally expensive when a high resolution is needed. The MPIC approach is particularly suitable for bin microphysics as a full size distribution can be advected simply by changing the coordinates of a parcel. This work will build on a collaboration with David Dritschel (University of St Andrews) and will also involve comparison to the Met Office’s CASIM (Cloud AeroSol Interactions Microphysics) scheme.