Collaborative Research: United States Cosmics Leaving OUtdoor Droplets (CLOUD) Consortium

This project will support the continued access of U.S. researchers to the CLOUD consortium at CERN to study the chemistry and physics that drive new-particle formation and growth in Earth's atmosphere. CLOUD is a unique state-of-the-art 26 cubic meter stainless-steel chamber with precise control over temperature and relative humidity. There is no chamber facility within the USA with these capabilities. Because these particles influence cloud formation and how energy moves through the atmosphere, this research helps improve our understanding of weather behavior and atmospheric conditions. Experiments over the next three years using the CLOUD chamber will include a focus on developing molecular descriptions of new particle formation and advancing parameterizations for use in scientific models. These experiments will include mixtures relevant to the upper atmosphere, with sulfuric and nitric acids, ammonia and other bases, and iodine oxidation products. The CLOUD experiments often lead to advances in instrumentation and provide an ideal test bed for new instruments. Students and early career researchers will be integrated into an international collaborative network of students and senior researchers and have the opportunity to work with some of the most highly regarded scientists worldwide in the study of aerosols and atmospheric chemistry. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.