Determination of the Rate of Nucleation of Aerosol Particles in Clear and Cloud-Processed Atmospheric Conditions

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

ATM-9732949 Russell This Faculty Early Career Development (CAREER) project in the Atmospheric Chemistry Program integrates a research and a teaching component into a five-year career plan. The research part of this plan undertakes a series of studies to advance our current understanding of both the chemical compounds and the meteorological conditions that are necessary for nucleation of new particles to occur in the atmosphere. The teaching part uses creative new technology-based resources to interest and teach students, incorporating important opportunities for mentoring students on their research and presentation skills. The research program applies the recently-developed technique of time-of-flight mass spectrometry to the little-understood mechanism of sulfuric acid-water nucleation, then extends this empirical evaluation of the nucleation rate to ternary mixtures with ammonia and to organic compounds. The strength of the approach is that it does not depend on bulk liquid properties to describe the behavior of clusters, and hence does not suffer from the associated uncertainties. The technique will integrate the mass spectrometric measurement technique with a variable-volume reactor vessel for generation of clusters in supersaturated conditions to allow the thorough characterization of the effect of mixing times on the observed nucleation rate. In parallel, modeling is used to investigate the effects of different boundary-layer and free-tropospheric conditions on the observed rate of nucleation. By implementing a unique new particle dynamics model with the capability to calculate the simultaneous nucleation, coagulation, condensation, and activation of externally-mixed populations of particles, the nucleation rate in areas of mixed aerosol populations are evaluated. These results have important implications for the possibility of nucleation of new particles in cloud outflow regions, as well as for regions of air where air masses mix. The teaching part of this career plan takes adva ntage of partnerships with four government-sponsored laboratories to use new technologies as teaching tools in the classroom. Students will discover the images provided by the latest satellite technologies and will experience a simulated 'research flight' aboard the NCAR C130 aircraft, to increase their interest in and knowledge of research in Atmospheric Chemistry. Undergraduate coursework will also incorporate relevant policy and economic information to highlight the importance of the Atmospheric Chemistry to political legislation and business decisions for the fraction of students planning to pursue careers in public policy, law, management, and education. Undergraduate and graduate thesis programs are both emphasized as techniques to teach students how to work on independent projects and to provide them with early encouragement for pursuing careers in science by interactions with researchers. Another important part of the mentoring included in this plan is directed toward correcting the reported shortcomings of women and other traditionally underrepresented students through the creation of additional speaking opportunities for students in courses and in a new seminar series for graduate students.