LASICSSACONST

LASIC SSA-constraint study

20 July 2017 - 12 September 2017

Lead Scientist: Paquita Zuidema

Observatory: AMF , ASI

The ability of black-carbon-containing smoke to absorb sunlight allows smoke to exert a warming on the Earth’s radiative climate. The intrinsic radiative property of smoke supporting the absorption, or the single-scattering-albedo (SSA), varies with composition, aging, and hygroscopicity. The SSA is still poorly constrained for smoke emanating from African continental fires after long-range transport. Filter-based techniques such as the Particle Soot Absorption Photometer (PSAP), nephelometers and aethalometers estimate extinction from the change in light transmission through particle-imbibed filters. The Cavity Attenuated Phase Shift (CAPS)-SSA uses entirely different approach. It utilizes a unique optical design to simultaneously measure aerosol light extinction and scattering in the same sample volume. These can then be used to derive the SSA and aerosol absorption. The CAPS-SSA absorption estimate will serve as a reference and anchor for the longer-term filter-based measurements, helping to fulfill an important goal of the LASIC campaign and of the ASR Aerosol Working Group. This endeavor is a joint effort between Aerodyne and DOE ARM.