Using the significant dust deposition event on the glaciers of Mt. Elbrus, Caucasus Mountains, Russia on 5 May 2009 to develop a method for dating and "provenancing" of desert dust events recorded in snow pack

Abstract

Abstract. A significant desert dust deposition event occurred on Mt. Elbrus, Caucasus Mountains, Russia on 5 May 2009, where the deposited dust later appeared as a brown layer in the snow pack. An examination of dust transportation history and analysis of chemical and physical properties of the deposited dust were used to develop a new approach for high-resolution "provenancing" of dust deposition events recorded in snow pack using multiple independent techniques. A combination of SEVIRI red-green-blue composite imagery, MODIS atmospheric optical depth fields derived using the Deep Blue algorithm, air mass trajectories derived with HYSPLIT model and analysis of meteorological data enabled identification of dust source regions with high temporal (hours) and spatial (ca. 100 km) resolution. Dust, deposited on 5 May 2009, originated in the foothills of the Djebel Akhdar in eastern Libya where dust sources were activated by the intrusion of cold air from the Mediterranean Sea and Saharan low pressure system and transported to the Caucasus along the eastern Mediterranean coast, Syria and Turkey. Particles with an average diameter below 8 μm accounted for 90% of the measured particles in the sample with a mean of 3.58 μm, median 2.48 μm. The chemical signature of this long-travelled dust was significantly different from the locally-produced dust and close to that of soils collected in a palaeolake in the source region, in concentrations of hematite. Potential addition of dust from a secondary source in northern Mesopotamia introduced uncertainty in the "provenancing" of dust from this event. Nevertheless, the approach adopted here enables other dust horizons in the snowpack to be linked to specific dust transport events recorded in remote sensing and meteorological data archives.

High-resolution provenance of desert dust deposited on Mt. Elbrus, Caucasus in 2009–2012 using snow pit and firn core records

“…The 700 hPa vector wind fields serve as a good indicator of potential dust transportation to the Caucasus (Shahgedanova et al, 2013). Data on surface and boundary layer wind speed in the potential source regions compared with the threshold for dust mobilisation defined by Chomette et al (1999) as 7-9 m s −1 confirmed potential for dust entrainment.…”

“…Rototaeva et al, 1998;, characteristics of mineral dust and its provenance was studied in relation to a single dust deposition event, which occurred on Mt. Elbrus on 5 May 2009 (Kokkalis et al, 2012;Shahgedanova et al, 2013). Using this deposition event, Shahgedanova et al (2013) developed a methodology for high temporal (ca.…”

“…Elbrus on 5 May 2009 (Kokkalis et al, 2012;Shahgedanova et al, 2013). Using this deposition event, Shahgedanova et al (2013) developed a methodology for high temporal (ca. hours) and spatial (ca.…”

“…Elbrus, northern Caucasus, Russia using snow pit and shallow firn core data. The specific objectives are to (i) date dust deposition events and establish their source regions building on the methodology proposed by Shahgedanova et al (2013); (ii) characterise meteorological conditions leading to dust deposition; (iii) characterise physical and, for part of the record, chemical properties of deposited dust; and (iv) attempt to establish links between physical and chemical properties of dust and its source regions.…”

“…Dust deposition events were dated and "provenanced" using methodology outlined in Shahgedanova et al (2013) in three iterations utilising independent techniques and datasets. Firstly, visual examination of snow and shallow core profiles for dust layers together with isotopic analysis and position of the dust layers in relation to ice crusts, enabled determination of the approximate (i.e.…”