Snow–Dust Storm: Unique case study from Iceland, March 6–7, 2013

• Published in: Aeolian Research
• Main Authors: Dagsson-Waldhauserova, P., Arnalds, O., Olafsson, H., Hladil, J. (Jindřich), Skála, R. (Roman), Navrátil, T. (Tomáš), Chadimová, L. (Leona), Meinander, O.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2015
• Subjects: snow dust deposition; atmosphere cryosphere interactions; volcanic dust; natural phenomenon; Arctic; Iceland; Sea ice
• Online Access: https://doi.org/10.1016/j.aeolia.2014.11.001; http://hdl.handle.net/11104/0245810

Iceland is an active dust source in the high-latitude cold region. About 50% of the annual dust events in the southern part of Iceland take place at sub-zero temperatures or in winter, when dust may be mixed with snow. We investigated one winter dust event that occurred in March 2013. It resulted in a several mm thick dark layer of dust deposited on snow. Dust was transported over 250 km causing impurities on snow in the capital of Iceland, Reykjavik. Max one-minute PM.sub.10./sub. concentration measured in Kirkjubæjarklaustur (20–50 km from the dust source) exceeded 6500 μg m.sup.−3./sup. while the mean (median) PM.sup.10./sup. concentration during 24-h storm was 1281 (1170) μg m.sup.−3./sup. Dust concentrations during the dust deposition in Reykjavik were only about 100 μg m.sup.−3./sup., suggesting a rapid removal of the dust particles by snow during the transport. Dust sample taken from the snow top layer in Reykjavik after the storm showed that about 75% of the dust deposit was a volcanic glass with SiO.sub.2./sub. ca 45%, FeO ca 14.5%, and TiO.sub.2 ./sub. ca3.5. A significant proportion of organic matter and diatoms was also found. This case study shows that severe dust storms are related also to meteorological conditions, such as winter snow storms, and moist conditions. Small volcanic dust particles deposited on snow tend to form larger particles (“clumping mechanism”) resulting in stronger light absorbance. This is one of the first reports on the “clumping mechanism” observed in natural conditions. The deposition of Icelandic dust on snow, glaciers and sea ice may accelerate the thaw, with the potential to increase the anthropogenic Arctic warming.