Submicrometer aerosols and excess CO as tracers for biomass burning air mass transport over southern Africa
Date
2016Author
Mafusire, Getrude
Beukes, Johan Paul
Josipovic, Miroslav
Van Zyl, Pieter Gideon
Laakso, Lauri
Metadata
Show full item recordAbstract
This paper links surface measurements of biomass burning aerosols and trace gases with
trajectory analysis to determine transport pathways for air masses with high and low concentrations. We
interpret the long-term atmospheric monitoring record from a remote monitoring station in central southern
Africa (North West Province, South Africa). Trace gas analyzers and a Differential Mobility Particle Sizer were
used to measure ground level trace gas and submicron aerosol concentrations. Fire signatures were
identified based on excess CO above average tropospheric levels, and episodes of enhanced particulate
matter concentrations in the 10 to 840 nm size range. Thirty-six biomass burning plumes were reported;
7 had strong signals of excess CO, with ratios between 0.41 and 0.64, while 29 had weak signals ranging
between 0.07 and 0.32. Pathways identifi ed for the long-range transport of biomass burning aerosols were
as follows: easterly (39% frequency), southwesterly (31%), recirculation (22%), and northerly (8%) flow
patterns. CO and Aitken-mode aerosol number strengths were larger for fire emissions arriving in the
easterly and southwesterly air masses than for recirculation and northerly air masses. Easterly and
southwesterly flows were dominated by Aitken-mode aerosol, whereas accumulation-mode particles
dominated in the recirculation and northerly flows. Findings identify biomass burning as a major source
of Aitken-mode aerosols. Enhanced CO concentrations, combined with Aitken- and accumulation-mode
particle number size distributions, are shown to provide a useful signature of plumes originating over
regional biomass combustion events
URI
http://hdl.handle.net/10394/19851https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2015JD023965
https://doi.org/10.1002/2015JD023965