Comprehensive Physical and Chemical Measurements to Test Predictions of Radiative and Hygroscopic Properties of Surface Atmospheric Aerosol

University Of Wyoming, Laramie WY

Investigators

Abstract

The primary goal of this project is to improve our understanding of the influence of atmospheric aerosols on climate. In particular, the relationships between aerosol composition and aerosol radiative and cloud droplet activation properties will be tested. The plan is to measure time-dependent variations of aerosol chemical composition across the particle size spectrum, and to examine how that variability affects calculated and measured optical and droplet-nucleating properties of the aerosol, as a function of particle size. An ancillary objective is to compare measurements made in a small urban environment with those at a remote mid-continental site, both in Wyoming. A comprehensive range of aerosol instruments will be employed to measure aerosol composition, size distribution, cloud drop nucleating properties, scattering at three wavelengths, and light absorption. Of particular importance will be the use of an aerosol mass spectrometer to measure the variability of particle size-resolved composition over time scales as short as a few minutes. These measurements, coupled with size distribution measurements, will permit optical and cloud condensation properties of the aerosol to be calculated with a similarly high time resolution, and compared with observations. Analysis of these comparisons will provide estimates of the importance of size and temporal variability of aerosol properties, and, thus, the appropriateness of model estimates which use averages of those properties to describe aerosol behavior. The analysis of these data sets will contribute to our understanding of the impacts of aerosol on the Earth's atmosphere. Additional broader impacts include capacity building at the University of Wyoming, and the training of a graduate student.