Optical imaging system for in situ characterization of mixed phase clouds

Clouds play leading role in the Earth's global energy and solar radiation balance. Improving cloud models requires information on the cloud microphysical properties, such as particle size distribution and concentration, cloud composition (droplets, ice particles) and also information on ice crystal shapes (habits). New lightweight and low power instruments for characterization of mixed-phase clouds, suitable for sampling from UAS, tethered balloons, or kite platforms, are needed. This SBIR project will extend the capabilities of the Mesa Photonics' optical imaging technology for cloud characterization. The proposed innovations will add the capabilities of discriminating between ice particles and water droplets, as well as sizing of droplets in mixed-phase clouds. In addition, high-resolution imaging options will be explored, which will allow determination of size and habit of ice particles. The ultimate goal is to develop a technology that is compact, lightweight, low power and inexpensive to make it compatible with small aerial platforms. The Phase I study will focus on: (1) implementation and characterization of the laboratory ice particle generation system based on rapid expansions of supercritical solutions of water in supercritical carbon dioxide, (2) characterization of polarization resolved side scatter imaging as a method of discriminating between ice particles and water droplets, (3) exploration of the possibilities of implementing high-resolution imaging to assess the ice particle habits, and (4) identifying the engineering challenges of adapting the technology to small aerial platform and designing a flight-ready prototype system in Phase II. The successful completion of this Phase I/II program will lead to development of a mixed cloud characterization technology primarily designed for use on small unmanned aerial platforms. 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 Earth’s 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 and volcanic ash plumes.