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 NASA and 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 the of 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.
By supporting this project, NASA would obtain airborne INP measurement capabilities that would support model validation and airborne science program field campaigns, similar to those discussed in the ROSES-2018 solicitation. Suitable platforms include the DC-8, P-3, C-20A and G-V. Relevant campaigns include any that include a focus on aerosol-cloud interactions, similar to FIREChem, NAAMES, ORACLES, ARISE II, CAMP2Ex and potentially those funded by the currently open EVS-3 solicitation.
Domestically, agencies with an interest in measuring INP from aircraft include the Department of Energy ASR/ARM, NOAA CSD, and NSF/NCAR atmospheric chemistry programs. Foreign government organizations include the UK MetOffice (BAe-146) and German DLR (G-V). Handix Scientific also has a close connection with investigators internationally because its owner is an atmospheric research instrument distributor for several US-based companies, and we anticipate interest from this emerging community.