The Photoacoustic Spectrometer (Photoacoustic Extinctiometer, PAX) measures optical properties of aerosols in real-time. The PAX spectrometer measures light absorption and scattering of atmospheric aerosols simultaneously at 405 nm wavelength. It provides the absorption coefficient (Babs), scattering coefficient (Bscat), and can derive other parameters, such as mass extinction coefficient and single scattering albedo. The instrument provides data with a one second time resolution and the high sensitivity of the instrument allows for probing particles with low concentrations. This instrument is particularly useful to study the optical properties of brown carbon aerosol.
Photoacoustic spectroscopy supports the Terrestrial-Atmosphere Integrated Research Platform by providing measurements for the scattering and absorption of particles. Measurements of optical properties is critical to improve the current understanding of the climate effects of organic aerosols, which have large uncertainties in current climate models. In addition, it can derive parameters, such as single scattering albedo—key for radiative forcing calculations and Earth’s energy budget.
Tips for success
- Aerosol samples can be either laboratory generated or ambient sampled.
- This instrument is field deployable.
- Samples can be collected on filters. Later extracted samples can be aerosolized and their optical properties measured.