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 (∼40 N, 115 E) on 16 June 2021 during two King-350 aircraft penetrations at temperatures between −4 and − 15 °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 °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.