Abstract
Particulate brown carbon (BrC) in the atmosphere absorbs light at subvisible wavelengths and has poorly constrained but potentially large climate forcing impacts. BrC from biomass burning has virtually unknown lifecycle and atmospheric stability. Here, BrC emitted from intense wildfires was measured in plumes transported over 2 days from two main fires, during the 2013 NASA SEAC4RS mission. Concurrent measurements of organic aerosol (OA) and black carbon (BC) mass concentration, BC coating thickness, absorption Ångström exponent, and OA oxidation state reveal that the initial BrC emitted from the fires was largely unstable. Using back trajectories to estimate the transport time indicates that BrC aerosol light absorption decayed in the plumes with a half-life of 9 to 15 h, measured over day and night. Although most BrC was lost within a day, possibly through chemical loss and/or evaporation, the remaining persistent fraction likely determines the background BrC levels most relevant for climate forcing.
Department
Earth Sciences, Earth Systems Research Center
Publication Date
6-3-2015
Journal Title
Geophysical Research Letters
Publisher
American Geophysical Union Publications
Digital Object Identifier (DOI)
10.1002/2015GL063897
Document Type
Article
Recommended Citation
Forrister, H., et al. (2015), Evolution of brown carbon in wildfire plumes, Geophys. Res. Lett., 42, 4623–4630, doi:10.1002/2015GL063897.
Rights
©2015. American Geophysical Union. All Rights Reserved.