Aircraft-based observations of ice concentrations in a midlatitude mixed-phase stratiform cloud system with embedded convection

This study analyzed in situ measurements of a mixed-phase stratiform cloud system observed over northern China (similar to 40 N, 115 E) on 16 June 2021 during two King-350 aircraft penetrations at temperatures between -4 and - 15 degrees C. Through a comparison of specific regions of mixed-phase and all ice, we investigated the inhomogeneity of ice particle concentrations and secondary ice production processes associated with rime splintering and collisional fragmentation. A multilayer structure of supercooled liquid water was observed, including extremely low liquid water content at approximately 7.5 km and a relatively higher liquid water content of 0.2 to 0.4 g m(-3) at 6 km. The cloud was horizontally inhomogeneous due to the presence of embedded convection. Ice particle concentrations at temperatures between -4 and - 8 degrees C varied from <10 L-1 to 80 L-1 in stratiform regions, and up to over 200 L-1 in embedded convective regions. There was evidence for the Hallett-Mossop process to account for secondary ice production in column and needle growth regimes. Collisional fragmentation may also occur in column-growth regimes of embedded convection.