(194d) Combined Ice Crystal Growth Chamber and Flow System to Investigate Atmospheric Secondary Ice Nucleation

At temperatures warmer than -40°C in the atmosphere, ice crystals can nucleate heterogeneously on a subset of aerosol particles, but observed ice crystal number concentrations often exceed corresponding ice-nucleating particle concentrations. An array of secondary production processes have been proposed to explain this discrepancy, including crystal breakup upon collision analogous to impact attrition within industrial crystallizers. We present a two-component lab setup to study these processes through the lens of secondary nucleation during crystallization. First, pristine ice crystals are grown in an air-filled nucleation chamber using distinct supersaturation and temperature histories to generate distinct habits. We characterize the temperature and supersaturation gradients and precisions within this chamber, as well as the array of resultant crystal geometries. Seed crystals are then transferred to a flow system where they are mounted atop a thermistor and contacting rod to perform collisions which are photographed with a high-speed, high-resolution camera. We show preliminary results of impact energy dependence in the ice crystal number generated by these collisions.