Dust Events Under Wind-Driven and Convective Transport of Dust Aerosol

Dust phenomena such as wind-blown sand transfer, dust devils and dust storms play a key role in the Earth's climate and geological processes. The main factor determining the removal of dust aerosol (0.1-5 μm in size) from arid areas is wind [1], resulting from the movement of large particles (70-150 μm in size) near the surface - saltation. In summer, under conditions of significant surface heating, convective movements have a significant effect [2]. As a result of impacts of particles moving in the flow, their charge changes, which is reflected in the measured values ​​of the electric field strength [3]. At high wind speeds, as during dust storms or inside dust vortices, these electric fields can be significant [4]. Under conditions of moderate wind and surface heating, according to comprehensive field measurements on sunny days (from 8 am to 8 pm) under conditions of intense convective movements, correlations between various parameters of the lower atmosphere are observed, differing depending on the time of day, heating and surface type. The measurements were carried out by the A.M. Obukhov Institute of Atmospheric Physics of the Russian Academy of Sciences in 2023 in the summer (July-August) in two different areas: a dune area (Naryn-Khuduk settlement, Kalmykia Republic) and a steppe area (Tsimlyansk, Rostov Region). A correlation was carried out for various pairs of quantities: temperature (T), wind speed (U), dust aerosol concentration (C), relative humidity (H), electric field strength (E). Correlation relationships are more pronounced in the morning or evening. The nature of the patterns for the arid and steppe zones is different, which, in particular, is associated with the mode of change in relative air humidity and the type of surface. It is necessary to assume that the transfer of particles in moderate wind with their electrification has a nature close to extreme processes. An increase in the area of ​​mobile sand territories (according to satellite images, observations), an increase in the number of particles participating in electrification, can affect the properties of dust transfer processes of various types, in particular, the parameters of dust events: weak and strong storms, as well as eddies. An analysis was carried out for 9 stations from 2011 to 2025: Yashkul, Komsomolsky, Elista, Utta, Liman, Remontnoye, Yusta, Lagan, Iki-Burul. The frequency of recording moderate and strong dust storms, as well as their duration, were analyzed. A tendency towards an increase in the duration of dust events for several stations was revealed. A statistical assessment of the frequency of dust eddies was carried out by the number of events per month, per year, as well as by the time of day when the event was observed. The relationship between the number of dust devils in the Komsomolsk region and meteorological parameters such as temperature, wind speed, and electric field strength, obtained experimentally in nearby arid areas, was studied. The study was supported by the Russian Science Foundation – project No. 25-17-00346.