AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Optical and Physical Properties of Biomass Burning Aerosols – Linking Laboratory and Field Measurements
ALLISON AIKEN, Manvendra Dubey, Shang Liu, Claudio Mazzoleni, Gavin McMeeking, Ezra Levin, Paul DeMott, Sonia Kreidenweis, Robert J. Yokelson, Allen Robinson, Neil Donahue, Christopher Cappa, Leah Williams, Nga Lee Ng, Douglas Worsnop, Timothy Onasch, Los Alamos National Lab
Abstract Number: 383 Working Group: Biomass Burning Aerosol: From Emissions to Impacts
Abstract Aerosols from biomass burning (BB) sources, e.g. wildfires and wood burning for heating, contribute substantially to global emissions and climate. Black carbon (BC) from BB alone accounts for ~50% of global BC emissions, equating to ~0.6 W/m2 atmospheric warming. However, large uncertainties exist due to the complex morphology and mixing state of BB aerosol. Direct on-line rBC (single particle soot photometer; SP2) and optical properties of scattering and absorption (3-wavelength Photoacoustic Soot Spectrometer; PASS-3) are combined from laboratory and field measurements in order to improve climate predictions. First, we explore the relationships between combustion characteristics, e.g. gas-phase emissions, and aerosol optical and physical properties by parameterizing single scatter albedo (SSA) and rBC as a function of modified combustion efficiency (MCE). Then, we investigate the presence of a BC-coating enhancement in an area impacted by BB. Lastly, we quantify a potential rBC removal technique utilizing the SP2 for implementation similar to the widely-applied thermal denuder method (Huffman et al., 2009). During the Fire Lab At Missoula Experiments IV (FLAME-IV), single-source BB emissions have an inverse relationship between SSA and MCE. Parameterization and application to wildfire data indicate agreement within 5% (Liu et al., 2014). rBC coatings measured with the SP2 are used to calculate the ratio of total particle diameter to rBC core, which also has an inverse relationship with MCE. Increased organic carbon during smoldering (MCE’s are <~0.9) supports this finding. Thickly-coated rBC that dominates BB emissions and rBC-inclusion particles (Sedlacek et al., 2012) are also compared from FLAME-IV and wildfires. A BC-coating enhancement of up to 50% was found during the ClearfLo campaign that occurred in winter with significant BB emissions from heating. A rBC removal method using the SP2 that can remove ≥90% of BC ≥100 nm dme is also evaluated for future climate applications.