Compact Cloud Condensation Nucleus Counter for Unmanned Aerial Systems (UAS) and Long-Term Monitoring Applications

Emissions from energy production and other anthropogenic activities are altering the physical and chemical properties of the atmosphere and have been linked to climate change, environmental degradation, human health problems, and changes in clouds and aerosols. Modelers of climate change require observational constraints on the particle cloud nucleating ability and hygroscopic growth in order to predict the effect of changing aerosol properties on cloud concentration nucleus (CCN) activity. Observations are particularly needed in the Arctic, where climate change is likely accelerating the ice melt. Because particles smaller than 200 nm diameter often control the CCN number concentration, and since particle size plays such an important role in determining whether a particle acts as a CCN, cloud condensation nucleus measurements are a key component of the suite of instruments necessary to reveal how changes in particle size, concentration and composition impact CCN concentrations and cloud radiative properties. This SBIR project will develop a new, miniaturized cloud condensation nucleus measurement system suitable for deployment on UASs in order to make observations 1) more often, 2) in more locations, 3) at reduced cost compared to conventional aircraft, and 4) in difficult to access regions such as the Arctic. Specifically, the project will support the development of: (1) a miniaturized water supersaturation chamber optimized for UAS deployment; (2) an interface to an existing miniature optical particle counter to detect grown droplets; (3) the prototype hardware and software to enable measurements of CCN concentrations at water supersaturations between 0.2 and 1%. Phase I of the project will involve coupled heat and mass transfer modelling of the water supersaturation generation system to reduce its size, weight and power consumption for deployment on the Tigershark, ScanEagle and other similarly sized UASs. The supersaturation chamber will be miniaturized for the small size requirements of the UAS and a prototype tested with known particle sizes and chemistries to assess performance. Commercial applications and other benefits include creating new, cost-effective tools to study aerosol forcing of climate, creation of data sets to validate climate change and urban air shed air quality models, measurements in health effects studies, flux measurements of aerosol species from ocean and land surfaces, studies of rapid aerosol evolution in power-plant plumes, monitoring of drug development by pharmaceutical firms, and providing sensors for indoor air quality monitoring for green buildings, industry and households.