This Small Business Technology Transfer Phase I project aims to prove the feasibility of developing a new in-situ instrument for measurement of the droplet size distribution and condensed water mass. This Cloud Spectrometer and Impactor (CSI) would be based on two existing technologies: the light-scattering spectrometer and the counterflow virtual impactor. Features of both instruments would be combined in a lightweight, compact, commercial instrument for measurement of cloud microphysical characteristics on an aircraft platform. Specifically, in Phase I the proposer would design two shrouded inlets for the CSI: one that impacts and evaporates droplets for a measurement of condensed water mass, and one that optically measures the droplet size distribution. A plan for incorporating all the necessary measurement and electronic components within the internal framework of a standard housing used on research aircraft would be developed. Methods for providing sufficient dry carrier gas, even at high-altitude, and would be assessed. Candidate techniques for measuring water vapor after droplets and ice crystals are impacted and evaporated within the CSI inlet would be evaluated. This instrument development focuses on an airborne instrument, but the feasibility of ground-based applications would be explored. Research organizations and industrial companies needing accurate measurements of the size and mass of condensed water will use this instrument. For research organizations, measurements of droplet size distribution and condensed water mass are important for weather forecasting and understanding global climate change. In industry, the application of agricultural chemicals and many coating processes rely on liquid water sprays. The accurate determination of the droplet size and total water content is important for correct application of the material.
