Inexpensive instrument for in situ cloud droplet/drizzle characterization

Stratus and stratocumulus clouds with low drop concentration and large drop diameter are scientifically very important, because this is the regime in which drizzle drops are formed. The formation of drizzle can lead to a rapid modification of the cloud droplet size distribution, which in turn has a strong influence on the cloud & apos;s radiative properties. Because stratus and stratocumulus clouds cover a large portion of the Earth, this process has a strong impact on the global radiative budget. New inexpensive, fast and lightweight technologies for cloud droplet/drizzle measurement in the size range of 101000 micrometers are needed. Vista Photonics proposes to develop an innovative, compact, lightweight and very inexpensive optical imaging technology for fast in situ cloud droplet/drizzle characterization, including measurement of droplet size distribution function and droplet number concentration. The expected droplet size range for the proposed instruments is from a few micrometers to 1000 micrometers, which exceeds the current solicitation requirements. The Phase I study will demonstrate the feasibility of the proposed technology, which will include (1) experimental determination of the sensitivity, droplet size measurement uncertainty and analysis of the random and systematic error sources, (2) evaluation of the limitations of the proposed method of drop sizing and number concentration measurement, (3) determining the engineering challenges to be addressed in the Phase II development, and (4) outlining the design of the Phase II flight-ready prototype instrument. When carried over into Phase III and beyond, this project will be of great benefit to the public and the Federal Government. Precise and extensive cloud characterization data will lead to better understanding of the contribution of atmospheric clouds to Earths radiative budget and climate change. Flexibility and low cost of the proposed technology will make it compatible with a variety of airborne- and ground-based platforms and suitable for other applications such as characterization of atmospheric aerosols, volcanic ash plumes and industrial/agricultural sprays.