An Airborne Continuous Flow Diffusion Chamber for Measuring Ice Nucleating Particles

Quantifying atmospheric aerosol, clouds and precipitation processes are critical needs for understanding climate and environmental change, a NASA objective. The formation of ice in the atmosphere depends on the nature and abundance of ice nucleating particles (INP), and has major implications for precipitation and cloud properties. Observational capabilities are required to advance understanding of INP, and there is a substantial gap between current needs within NASAnbsp;and existing instruments and capabilities. This project seeks to develop a new commercial instrument for airborne INP measurements based on the continuous flow diffusion chamber (CFDC) concept. The CFDC approach involves exposing sampled aerosol to a region between two ice-covered walls and measuring ice crystals that form from sampled INP. Phase I work assessed a measurement chamber made from anodized aluminum and found it was suitable for INP measurements. Phase II will build on this work by completing a prototype instrument featuring an aluminum-walled chamber. Research and development efforts will include testing and design of a new inlet system to reduce sampling artifacts, incorporation of a new refrigeration system for use on aircraft, and implementation of several automation features into the overall instrument design. The prototype instrument will be thoroughly tested using aerosol standards, including previously characterized INP, and compared with state-of-the-art measurement methods available from our project partner, Colorado State University. At the end of the project we will provide NASA with a characterized, prototype instrument capable of INP measurements aboard the NASA aircraft fleet. The project directly addresses the NASA need for measurement capabilities to support current satellite and model validation by providing an instrument capable of measuring INP concentration in an airborne deployment, as identified in subtopic S1.08, In Situ Sensors and Sensor Systems for Earth Science.