This POWRE project will involve the investigation of the fundamental physical, optical and thermodynamic properties of atmospheric aerosols with compositions relevant to polar stratospheric clouds. The specific objectives for this research are: (1) to produce model aerosols based on atmospheric field observations, (2) to develop the ability to control a particle's environment (temperature and gas phase composition), (3) to develop the capability to produce supersaturated gas phase compositions to simulate cloud chamber conditions, (4) to define the phase transformation conditions for suspended, single particle aerosols of lower stratosphere and upper troposphere importance, (5) to produce multi-component phase diagrams for equilibrium and non-equilibrium phase transitions in pressure, temperature and composition domains. A new low-temperature single particle apparatus will be designed and constructed. This particle levitation chamber will be capable of reproducing temperatures, cooling rates, and gas phase compositions similar to those prevalent in the upper troposphere and lower stratosphere. In addition, with certain modifications, this apparatus will serve as a single solid-particle cloud chamber. For the characterization of atmospheric aerosols, particle mass and Mie scattering will be used to determine the optical and thermodynamic properties, while Raman spectroscopy will be employed for determining the chemical composition and physical phase. The results from this investigation will define the actual aerosol composition, physical phases, and the transformations that can occur under conditions seen in the polar stratosphere. This POWRE award will allow the PI to work closely with scientists at Brookhaven National Laboratory, where the new apparatus will be located. The PI will gain additional research experience in atmospheric chemistry, and her students will have the opportunity to get involved in state-of-the-art science.
