In the past few years, laboratory experiments have advanced our understanding of the microphysics of mesospheric ice particles. Important parameters for the nucleation have been determined, such as the contact parameter, the desorption energy and the saturation vapor pressure over ice at mesospheric temperatures. Further, the absorption of visible light by meteoric smoke particles (MSPs) and the following increase of the MSP equilibrium temperature have been confirmed.

We incorporated the laboratory results into the Community Aerosol and Radiation Model for Atmospheres (CARMA) and studied the development of polar mesospheric clouds (PMCs). The experimentally determined desorption energy and contact parameter lead to nucleation rates which are many orders of magnitude larger than those currently assumed. The resulting PMCs are characterized by high ice particle number densities and rather small radii.
MSPs acquire an equilibrium temperature which depends on their size and composition and which can be several Kelvin higher than the temperature of the surrounding atmosphere. As a result, the nucleation of those warmer MSPs is inhibited, which is a significant effect in particular for larger MSPs. We find that only the smaller MSPs close to the critical radius are relevant for the formation of PMCs.
Furthermore, we discuss the effect of different ice phases (amorphous ice and stacking disordered ice) which form in different temperature regimes and demonstrate the challenge to model PMCs in a gravity wave perturbed background when considering all microphysical details.