AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Observations on Aging of Biomass Burning Aerosols in Southern Africa
VILLE VAKKARI, Veli-Matti Kerminen, Johan Paul Beukes, Petri Tiitta, Pieter G. van Zyl, Miroslav Josipovic, Andrew D. Venter, Kerneels Jaars, Douglas Worsnop, Markku Kulmala, Lauri Laakso, Finnish Meteorological Institute, Helsinki, Finland
Abstract Number: 482 Working Group: Biomass Burning Aerosol: From Emissions to Impacts
Abstract Aerosol particles originating from biomass burning contribute significantly to the atmospheric aerosol budget and thereby to both direct and indirect radiative forcing. A large number of studies have been carried out to characterize biomass burning aerosol in the immediate vicinity of fires, but less information is available on atmospheric aging of the emissions. In this study, combining remote sensing fire observations to ground-based long-term measurements of aerosol particle and trace gas properties at the Welgegund measurement station in South Africa (www.welgegund.org), we have been able to follow the time evolution of biomass burning plumes up to several hours in the atmosphere in both day and night time conditions.
Based on observations of 60 biomass burning plumes of variable age, we show that the climatically most important properties of biomass burning aerosols change rapidly and to a substantial degree during the first two to four hours of their atmospheric transport in most plumes. The changes in particle size distribution and chemical composition, driven by atmospheric oxidation and subsequent secondary aerosol formation, may reach a factor >10 increase in the cloud condensation nuclei concentration and a factor of 6 increase in the aerosol scattering coefficient.