The presentation highlighted that the long-range transported mineral dust has a wide range of direct and indirect effects as a pollutant, nutrient and climate-forcer. Until now, the northward transported mineral dust from arid-semiarid areas has been only episodically documented. In Varga et al. (2023), the first systematic long-term data for dust storm events from lower latitudes reaching the Finnish atmosphere are presented, based on the MERRA-2 satellite data, meteorological observations, and modelling results.
In her talk at the Second Environmental History Day of Finland, Outi Meinander also described two cases of Saharan dust deposition on snow, in northern Finland in 1991; and in southern Finland in 2021 with a successful citizen science campaign (work lead by Outi Meinander, manuscript accepted).
In Varga et al. (2023), in total 86 long-range dust transport events were identified between 1980 and 2022, when air masses loaded with dust reached Finland. Based on backward-trajectories the following different sources were identified: 59 were Saharan, 22 were Aral-Caspian, and five were associated with Middle Eastern source areas. A clear maximum of dust events in spring (60%), followed by summer and autumn (where 10 of the 11 autumn episodes were from the Sahara) was found. However, the number and proportion of scarce winter events have more than doubled since 2010 compared to the preceding 30 years.
Reference
Varga G, Meinander O, Rostási Á, Dagsson-Waldhauserova P, Csávics A, Gresina F. Saharan, Aral-Caspian and Middle East dust travels to Finland (1980-2022). Environ Int. 2023 Oct;180:108243. doi: 10.1016/j.envint.2023.108243. Epub 2023 Sep 29. PMID: 37804716, 2023.