| Summary: | Light-absorbing impurities (LAI) deposited on snow and ice have been found to affect their albedo and melting processes. Reduced albedo of snow and increased melting can lead to less snow cover revealing dark ground underneath, causing a positive feedback loop. One of the most important LAI is considered to be black carbon (BC), but for some areas volcanic dust has been at times found to have a more significant impact on the snow surface albedo because of high dust emissions. For the Arctic areas, Iceland is the most important high-latitude dust source. This work focuses on studying the optical properties of Icelandic volcanic dust to understand how it interacts with Sun’s radiation and estimate how this affects the areas of deposition. Optical properties of Icelandic volcanic sand samples were measured at the laboratory of the Finnish Geospatial Research Institute (FGI) in Espoo, Finland using the latest setup of the FGI’s goniospectrometer. We found that, depending on the particle size, the albedo of dry volcanic dust on the visible spectrum can be as low as 0.03, which is similar to that of BC, further supporting the suggestion that volcanic dusts can be comparable to BC as strong LAI and highlighting the importance of Icelandic volcanic dust’s role as an albedo reducing impurity on snow and ice in the Arctic areas.
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