Sensitivity studies on secondary ice processes using detailed microphysics scheme

Ice formation in clouds occurs over a wide temperature range (-5°C to -40°C) during primary and secondary ice formation. In most clouds, primary ice formation (PIP) is generated by ice-forming aerosol particles (INP) through heterogeneous nucleation. Observations show that the concentration of ice crystals often exceeds the concentration of available active ice nuclei. This suggests that ice crystals can be generated by secondary processes (SIP). In contrast to PIP, the range of possible processes for SIP is not yet fully understood.

The aim of this study is to identify what are the dominant SIP mechanisms at different environmental conditions, such as temperature, liquid water content, primary ice formation and different CCN and INP concentrations.

At the current state of the research we have performed numerical experiments to study the impact of the different ice splintering mechanisms (due the freezing of the water drops; ice – ice collision and Hallett-Mossop process) at different environmental conditions. A detailed microphysics scheme (University of Pécs-NCAR Bin scheme) implemented in a 2D kinematic framework were used to perform the numerical experiments.