AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Studies of the Optical Properties of Mineral Dust Aerosol from the IR to the Visible
JENNIFER ALEXANDER, Olga Laskina, Brian Meland, Vicki Grassian, Mark Young, Paul Kleiber, University of Iowa
Abstract Number: 38 Working Group: Remote and Regional Atmospheric Aerosols
Abstract Atmospheric dust plays a key role in the Earth’s radiation balance, affecting climate forcing by direct and indirect means. Accurately treating the radiative transfer effects of dust requires knowledge of aerosol concentration, composition, size, and shape distributions. While much of this information can be obtained from satellite or ground-based remote sensing measurements, the retrieval algorithms depend on precise models of the aerosol optical properties. Unfortunately, accurate modeling of dust optical properties is complicated because atmospheric dust particles are typically irregular in shape and can be an inhomogeneous mixture of different minerals.
In this work, infrared extinction and visible phase functions and polarization profiles are measured for complex authentic dust samples including Saharan sand and Iowa loess. Particle size distributions are measured simultaneously along with the optical properties. These complex dust mixtures are modeled as external mixtures of mineral dust components. Experimental data are compared with T-Matrix theory simulations using a priori particle shape models for each mineral component. The success of this approach is highlighted for these complex dust mixtures.