AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Analysis into the Microphysical Properties and Behaviour of Black Carbon Aerosol
JAMES BROOKS, University of Manchester
Abstract Number: 483 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Black Carbon (BC) aerosol is a carbonaceous material formed during combustion of fossil fuels, amongst other carbon sources. BC is often referred to as soot, and is characterised by strong visible light absorption, giving it a large radiative forcing potential. Despite BC being studied for many years now, its definition and understanding remains ambiguous due to the quality of different measurement techniques. Filter based methods have been used extensively, but include inherent inaccuracies and sampling issues (Bond et al, 2013). The use of an instrument based on laser induced incandescence (LII) has sought to eliminate such inaccuracies and has become much more common in BC measurement and detection (Moteki and Kondo, 2010). The method of LII used in the research as part of my PhD will be a Single Particle Soot Photometer (SP2), which will provide various microphysical and optical properties of BC aerosol. A beam of BC particles, on a particle-by-particle basis, will pass through a 1064nm laser beam and be heated up to temperatures of 4000K. At this high temperature, the BC particle will incandesce (vaporize) and will give information about its mass, size, composition and mixing state.
When freshly emitted, BC-containing particles are generally hydrophobic (don’t readily mix with water) but with time they become hydrophilic (interact with water) through aging, which have impacts on the optical properties and mixing state of the particles (Ohata et al, 2016). The measuring of BC mixing state is not sufficient across the Earth, so large uncertainties surrounding BC climate forcing exist (Taylor et al, 2015; Willis and Healy, 2015).
I will be operating the SP2 instrument, amongst others, as an instrument-operator on-board the FAAM BAe-146 Research Aircraft, carrying out fieldwork on two campaigns. Firstly SWAAMI (South-West Asian Aerosol Monsoon Interaction) studying BC and dust properties across India, and secondly CLARIFY-2016 (Cloud-Aerosol-Radiation Interaction and Forcing – Year 2016) looking at the interaction of biomass-burning aerosol and clouds over the SE Atlantic. I will present preliminary results, in a poster format, from both campaigns.