The area from the west Sahara through the Middle East and Central Asia to the Gobi desert is often called the “dust belt,” an expansive region where winds stir up frequent and often severe dust storms.
The dust belt consists of natural dust sources, such as the Sahara and Gobi deserts, and human-induced sources like the Aralkum, the arid and salty swathe in Kazakhstan and Uzbekistan that continues to emerge as the inland Aral Sea dries. In a changing climate, the countries located in this area suffer from the dust in a variety of ways because of its negative effects on air quality, human and environmental health, and economic activity, for example. Furthermore, dust originating from sources in the dust belt does not just stay local but is also distributed by wind and weather to remote regions. It is thus important to better understand the composition, transport, and effects of the dust.
The first Central Asian Dust Conference (CADUC) took place recently in Dushanbe, Tajikistan, bringing together about 80 scientists from 17 countries. Four topics were addressed at the conference: dust at sources, dust in transport, dust sinks, and the impacts of dust. Six extended oral contributions presented overviews of the topics of the conference, whereas another 43 talks reported specific research results.
The first session comprised presentations of studies on dust sources, which are often made using space-based observations. Outputs of these investigations reported at the conference included new inventories of dust sources; parameters and methods for the assessment of dust sources; characteristics of recently developing sources, such as Lake Urmia in Iran; the observation that saline dust storms are becoming more frequent; dust flux estimates; and identification of dust transport pathways in western Asia.
Results reported during the second session focused on particle properties and measurements of long-range transported dust from the Sahara to East Asia; dust lofted up to heights of 11 kilometers; the mixing and aging of dust with other particles; parameters for identifying dust from remote and in situ observations and for the representation of dust in models; vertically resolved, ground-based dust measurements in Central Asia; long-term, space-based, and vertically resolved dust measurements from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument, part of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission; the electrostatic charging of dust during atmospheric transport; and long-range dust transport from the dust belt to places as far away as Moscow.
In the third session, participants discussed the chemical and mineralogical constituents of Central Asian dust with comparisons to Saharan dust; Aralkum as a human-made dust source; possible, although not yet identified, pathways of dust down mixing in the atmosphere; mixing of dust with particles produced through anthropogenic activity in Central Asia; and dust transported to regions west and north of Central Asia such as Georgia and Siberia.
The fourth session addressed the impacts of dust. Following a broad overview about dust hazards, several presenters examined meteorological impacts of dust resulting from its ability to serve as ice-nucleating particles and alter radiative fluxes. Additionally, speakers presented results from studies of the health impacts of dust containing toxic metals, bacterial transport over long distances aboard dust, how different dusts affect bacterial survival, and plant growth under dust-induced stress.
All abstracts from the conference are open access and are published in the conference proceedings. Conference participants agreed that future CADUC meetings should be held to follow up on this first conference.
We are very grateful to the nonprofit Volkswagen Foundation for its support of the conference.
Dietrich Althausen ([email protected]), Leibniz Institute for Tropospheric Research, Leipzig, Germany; Sabur Abdullaev, Physical-Technical Institute of the Academy of Sciences of Tajikistan, Dushanbe; and Julian Hofer, Leibniz Institute for Tropospheric Research, Leipzig, Germany