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 NASAand existing instruments. This project develops a new commercial instrument for airborne INP measurements based on the continuous flow diffusion chamber (CFDC) concept. The CFDC approach involves exposing sampled aerosol in a region between two ice-covered walls and measuring ice crystals that form. In Phase I, we seek to test new wall materials necessary for wider-spread use and commercialization of the CFDC technology. Wall materials used in current versions of the CFDC require frequent cleaning, chemical treatment, and re-assembly, which makes its use by NASA prohibitively costly. Tests proposed include characterizing the thermal and other properties of the proposed wall materials, assessing their performance in terms of INP measurement sensitivity when applied in a basic laboratory configuration, and evaluating their longevity and stability necessary for use in a sustainable measurement platform. An evaluation of the test results will identify a suitable wall material for future development efforts would be theof Phase II, which has the deliverable of producing a prototype INP measurement system suitable for autonomous operation onboard research aircraft. The project directly addresses the NASA need for measurement capabilities to support current satellite and model validation by providing an instrument capable of measuring ice nucleating particle concentration in an airborne deployment, as identified in subtopic S1.08, In Situ Sensors and Sensor Systems for Earth Science.