A global study of hygroscopicity-driven light-scattering enhancement in the context of other in situ aerosol optical properties ...

• Main Authors: Titos, Gloria, Burgos, María A., Zieger, Paul, Alados-Arboledas, Lucas, Baltensperger, Urs, Jefferson, Anne, Sherman, James, Weingartner, Ernest, Henzing, Bas, Luoma, Krista, O'Dowd, Colin, Wiedensohler, Alfred, Andrews, Elisabeth
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus 2021
• Subjects: 620 - Ingenieurwissenschaften und Maschinenbau; Arctic
• Online Access: https://dx.doi.org/10.26041/fhnw-7634; https://irf.fhnw.ch/handle/11654/43693

The scattering and backscattering enhancement factors (f(RH) and fb(RH)) describe how aerosol particle light scattering and backscattering, respectively, change with relative humidity (RH). They are important parameters in estimating direct aerosol radiative forcing (DARF). In this study we use the dataset presented in Burgos et al. (2019) that compiles f(RH) and fb(RH) measurements at three wavelengths (i.e., 450, 550 and 700 nm) performed with tandem nephelometer systems at multiple sites around the world. We present an overview of f(RH) and fb(RH) based on both long-term and campaign observations from 23 sites representing a range of aerosol types. The scattering enhancement shows a strong variability from site to site, with no clear pattern with respect to the total scattering coefficient. In general, higher f(RH) is observed at Arctic and marine sites, while lower values are found at urban and desert sites, although a consistent pattern as a function of site type is not observed. The backscattering ...