AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Revisiting Particle Dry Deposition: Observational Constraints of Submicron Aerosol and Black Carbon Fluxes
Delphine K. Farmer, ETHAN EMERSON, Holly DeBolt, Gavin McMeeking, Joshua P. Schwarz, Joseph Katich, Colorado State University
Abstract Number: 247 Working Group: Remote and Regional Atmospheric Aerosol
Abstract Dry deposition is a key process that removes particles from the atmosphere, and thus one factor that controls aerosol lifetime. Despite its importance, there are few measurements of particle dry deposition, and constraining model parameterizations has been challenging. Here, we use eddy covariance flux measurements of size-resolved sub-micron particle fluxes to investigate dry deposition over two terrestrial surfaces, including a ponderosa pine forest in Colorado and an agricultural site in Oklahoma. We contrast these observations with previous measurements in the literature, and with commonly used resistance models, highlighting several model-measurement discrepancies. To further investigate the mechanisms of dry deposition, we use black carbon deposition as an inert tracer for particle wet and dry deposition. We show that wet deposition dominates in the agricultural environment, and can provide observational constraints on black carbon lifetime in the region. Finally, size-resolved measurements of black carbon flux, with and without coatings, provides new insight into particle dry deposition mechanisms and our ability to capture this process with current models.