The Lagrangian ice microphysics code LCM: Introduction, current developments and benefits

The Lagrangian Cirrus Module (LCM) is a Lagrangian (also known as particle-based) ice microphysics code that is fully coupled to the large-eddy simulation (LES) code EULAG. The ice phase is described by a large number of simulation particles (order 10⁶ to10⁹) which act as surrogates for the real ice crystals. The simulation particles (SIPs) are advected and microphysical processes like deposition/sublimation and sedimentation are solved for each individual SIP. More specifically, LCM treats ice nucleation, crystal growth, sedimentation, aggregation, latent heat release, radiative impact on crystal growth, and turbulent dispersion. The aerosol module comprises an explicit representation of size-resolved non-equilibrium aerosol microphysical processes for supercooled solution droplets and insoluble ice nuclei.

First, an general introduction to particle-based microphysics coupled to a grid-based (Eulerian) LES model is given.
In the following, emphasis is put on highlighting the benefits of the Lagrangian approach by presenting a variety of simulation examples.