Icelandic volcanic snow-dust storm transported dust over 250 km and caused a dark layer of dust on snow

An Icelandic-Norwegian-Czech-Finnish research group has published a unique case study on a snow-dust storm from Iceland. The work appears in Elsevier's Aeolian Research.

Iceland is likely the largest and most active high-latitude dust source, where dust deposition is expected to influence an area of > 500,000 km2. 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.

The paper shows the investigation of 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 PM10 concentration measured in Kirkjubæjarklaustur (20-50 km from the dust source) exceeded 6500 µg m-3 while the mean (median) PM10 concentration during 24-hour storm was 1,281 (1,170) µg m-3. Dust concentrations during the dust deposition in Reykjavik were only about 100 µg m-3, 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 SiO2~ 45 %, FeO~14.5 %, and TiO2~3.5. 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. The deposition of Icelandic dust on snow, glaciers and sea ice may accelerate the thaw, with the potential to increase the anthropogenic Arctic warming.The work was supported by the Eimskip Fund of The University of Iceland, and the Nordic Center of Excellence (NCoE), Nordic Top Research Initiative "Cryosphere-atmosphere interactions in a changing Arctic climate" (CRAICC).

More information:

Outi Meinander, Finnish Meteorological Institute, outi.meinander@fmi.fi

Citation: Dagsson-Waldhauserova P., Arnalds O., Olafsson H., Hladil J., Skala R., Navratil T., Chadimova L., Meinander O., 2014. Snow-Dust Storm: Unique case study from Iceland, March 6-7, 2013. Aeolian Research, DOI: 10.1016/j.aeolia.2014.11.001.