Singular versus Time-dependent Approach of Heterogeneous Ice Nucleation and Secondary Ice Production in Contrasting Clouds Simulated Numerically

Two approaches of heterogeneous ice nucleation have been proposed in previous studies. These are the singular approach (time-independent), and time-dependent approach. The present study numerically analyses the effect from the time-dependent approach of ice nucleation in deep convective, orographic, and supercooled stratiform clouds, sampled by aircraft. It is predicted that in all the simulated clouds, the singular approximation is a good representative of heterogeneous ice nucleation. At levels warmer than -36^oC, the inclusion of time-dependence is predicted to form only about 10 % of the total ice, whereas secondary ice processes (the Hallett-Mossop process and fragmentation during ice-ice collisions, raindrop-freezing, and sublimation) form about 90 % of the total ice at these levels. The present study uses the ‘Aerosol-Cloud’ (AC) model. The AC represents microphysical species as rain, cloud-ice (‘crystal’), snow, and graupel/hail and treats cloud properties with a hybrid spectral bin, and two-moment bulk microphysics schemes. Also, radiative effects from ice nucleating particles on the simulated deep convective and orographic clouds will be discussed.