A Summary and Comparison of Aerosol Properties Measured during Recent International Field Campaigns (ACE 1, ACE 2, TARFOX, and INDOEX)

Satellite observations are used to derive regional and global-scale distributions of aerosol properties including aerosol optical depth. Inherent in satellite retrievals is the use of an aerosol model that assumes certain aerosol physical, chemical, and optical properties. The accuracy of the retrieved aerosol parameters depends, in part, on the accuracy of the assumed aerosol model. In addition coupled chemical transport-climate models are used to estimate radiative forcing by multiple aerosol chemical components on global scales. Initiation or validation of the models with measured aerosol properties is needed to ensure model accuracy. Several international field experiments have been conducted since 1995 to measure many of the aerosol properties required for accurate satellite retrievals of aerosol parameters and model estimates of aerosol radiative forcing. These include the first and second Aerosol Characterization Experiments (ACE 1 and ACE 2), the Tropospheric Aerosol Radiative Forcing Observation Experiment (TARFOX), and the Indian Ocean Experiment (INDOEX). A summary and comparison of aerosol properties measured during these field campaigns will be presented.

Aerosol properties to be presented include size distribution modal parameters (geometric mean surface area diameter, total surface area concentration, and geometric standard deviation), Angstrom exponent derived from multi-wavelength nephelometer and sunphotometer measurements, mass concentration of the major aerosol chemical components, single scattering albedo, backscattered fraction, and aerosol optical depth. Mean values, the variability about those means, and associated uncertainties for the different geographical regions and aerosol types studied will be presented.