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

California Institute Of Technology, Pasadena CA

Investigators

Abstract

This project will support the continued membership of Carnegie Mellon University, the California Institute of Technology, and the University of Colorado at Boulder in 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 state-of-the-art 26 cubic meter stainless-steel chamber with precise control over temperature and relative humidity. The new research at CLOUD will focus on the study of chemical mechanisms that generate extremely low volatility organic compounds capable of nucleating and condensing onto freshly nucleated particles. Target environments include natural (both forest and marine) and polluted (urban) conditions, as well as cold temperatures characteristic of the free troposphere. Planned research over the next 3 years, includes studies of: (1) aging of first-generation organic oxidation products under conditions found in the free troposphere; (2) measurement and modeling of key radical intermediates in organic oxidation and also inorganic sulfur, nitrogen, and iodine oxidation, as well as interaction between organic and inorganic systems; (3) measurement and modeling of interactions among vapors and both charged and neutral particles below 10 nm to constrain key microphysical terms; and (4) propagating CLOUD results to atmospheric models, testing their capability to explain field measurements, and understanding the implications of improvements to models for aerosol radiative forcing. In addition to providing the required consortium fee, this project will support shipping and travel to CLOUD experimental campaigns and associated consortium meetings and data workshops. Both doctoral and postdoctoral students associated with the project (supported by other awards) are integrated into an international collaborative network of students and senior researchers who work with some of the most highly regarded scientists 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.