Sensitivity of Lake-Effect Cloud Microphysical Processes to Ice Crystal Habit and Nucleation during OWLeS IOP4

Ice crystal habit significantly impacts ice crystal processes such as growth by vapor deposition. Most bulk microphysical models disregard this natural shape effect and assume ice to grow spherically. However, few models exist that allow for ice crystals to grow non-spherically. This study focuses on how the evolution of ice crystal shape and choice of ice nucleation parameterization in the Adaptive Habit Model influence the lake-effect storm that occurred during IOP4 of the Ontario Winter Lake Effect Systems (OWLeS) Field Campaign. This intense, localized snowstorm produced liquid-equivalent precipitation amounts up to 17.92 mm during a 16-hour time period, providing a natural laboratory to investigate the ice-liquid partitioning within the cloud, various microphysical process rates, and accumulated precipitation magnitude and spatial distribution. Two nucleation parameterizations were implemented and highly-resolved aerosol data from the Advanced Particle Microphysics model were ingested into the Adaptive Habit Model for use as ice and cloud condensation nuclei. Simulations that allowed ice crystals to grow non-spherically produced greater magnitudes of precipitation while altering the nucleation parameterization influenced the inland extent of the precipitation. In addition, all simulations were highly sensitive to the domain resolution and the source of initial and boundary conditions. These findings begin to form the foundational understanding of the relationship among ice crystal habit, nucleation parameterizations, and resultant cold-season mesoscale precipitation within bulk microphysics models.