Effects of relative humidity on aerosol light scattering. results from different European sites ...

• Main Authors: Zieger, Paul, Fierz-Schmidhauser, Rahel, Weingartner, Ernest, Baltensperger, Urs
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus 2013
• Subjects: 550 - Geowissenschaften; Arctic; Mace; Ny-Ålesund; Ny Ålesund; Spitsbergen
• Online Access: https://dx.doi.org/10.26041/fhnw-8173; https://irf.fhnw.ch/handle/11654/44372

The effect of aerosol water uptake on the aerosol particle light scattering coefficient (σsp) is described in this study by comparing measurements from five European sites: the Jungfraujoch, located in the Swiss Alps at 3580 m a.s.l.; Ny-Ålesund, located on Spitsbergen in the Arctic; Mace Head, a coastal site in Ireland; Cabauw, a rural site in the Netherlands; and Melpitz, a regional background site in Eastern Germany. These sites were selected according to the aerosol type usually encountered at that location. The scattering enhancement factor f(RH, λ) is the key parameter to describe the effect of water uptake on the particle light scattering. It is defined as the σsp(RH) at a certain relative humidity (RH) and wavelength λ divided by its dry value. f(RH) at the five sites varied widely, starting at very low values of f(RH = 85%, λ = 550 nm) around 1.28 for mineral dust, and reaching up to 3.41 for Arctic aerosol. Hysteresis behavior was observed at all sites except at the Jungfraujoch (due to the absence ...