Effect of sulfate aerosols on cloud drop-sizes: A case study of the eastern United States
Abstract
The North Eastern United States is a concentrated source of sulfur dioxide from power plants and industries in regions like the Ohio valley. Sulfates from this region are carried out over the Atlantic by the prevailing winds. Effective drop-sizes retrieved from low oceanic clouds in the Atlantic off the Eastern U.S. coast are analyzed in an attempt to look for a signal of the indirect radiative effect of changes in cloud microphysics. Cloud droplet sizes are retrieved for these clouds from AVHRR data for clouds over polluted and cleaner areas. The areas are categorized as polluted or clean based on information from the Regional Acid Deposition Model (RADM) sulfate concentration simulations as well as retrieved aerosol optical thicknesses derived from reflectances obtained in the various AVHRR channels. Analysis of the limited data indicates that while aerosols do impact cloud drop sizes, other variables which affect drop size distributions need to be accounted for in attempting to quantify aerosol-cloud interactions. It is also possible that some kind of saturation effect is observed in cases of very high pollution which occur after days of a pollution episode.
Degree
Ph.D.
Advisors
Major Professor: Harshvardhan, Purdue University.
Subject Area
Atmosphere
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