On 21 February 2016, a very intense dust outbreak caused severely reduced visibility conditions and remarkable dust deposition in Spain. The dust event was generated again by an atmospheric cut-off low separated from a deepened upper-level through, which low pressure system transported large amounts of the mineral dust northward from salt lakes of high plateau region situated between the Tell Atlas and Saharan Atlas Range (can be classified as a mixture of Type-1 and Type-3 situations). An exceptionally intense wet deposition event was observed on 23 February in Budapest, Hungary, where the deposited reddish-yellow dust material has blanketed parking cars and other exposed obstacles.
Granulometric characteristics of collected samples was dominated by clay and fine silt-sized particles (mostly quartz, calcium-carbonate and dolomite), the modal circle-equivalent volumetric diameter of the log-normal grain size distribution was ~10 µm. The value of the granulometric convexity (edge roughness of particles, where higher values indicate smoother particle shapes) of the measured particles was higher compared to the results of event observed on 19 September 2015, indicating a higher individual grain per aggregate ratio.
Another unusually intense dust deposition event was observed on 29 February 2016 in Budapest and widespread in the country. The yellowish dust material was transported from Algerian, Tunisian and Libyan source areas at the foreside of a deep cyclone centred above the western basin of Mediterranean Sea (Type-2 Saharan dust event). Particles deposited in the area have a modal circle-equivalent volumetric diameter of ~8 µm with a clear abundance of quartz minerals.
No comments:
Post a Comment