New Study Reports on Consistent Dust Electrification from Arabian Gulf Sea Breezes
Electrification of dust in the atmosphere occurs as a result of contact charging or triboelectrification during dust generation or its atmospheric transport. Dust is lifted from the surface by the wind, and enhanced by saltation and resuspension. Collisions between dust particles cause charge to be transferred between them, resulting in a net charge on the particles depending on particle size and composition. Dust electrification has applications to climate studies, through electrical influences on the behavior of dust and its radiative transfer implications.
To gain a better understanding of the physical processes by which dust becomes electrified, Giles Harrison, Professor of Atmospheric Physics at the University of Reading in the United Kingdom and a second cycle awardee by the UAE Research Program for Rain Enhancement Science (UAEREP), recently collected a unique dataset of atmospheric electrical measurements from a site in Al Ain, UAE.
The measurement site is a receptor of frequent dust events of remarkable consistency, providing a new opportunity for studying dust charging processes in a repeatable natural system.
The polarity of the charge observed during the passage of each of the 80 studied sea breeze events was positive in every case. This is an opposite polarity to many previous measurements reported in dust storms in the literature. This suggests the important role of complex mineralogy of dust particles over the UAE which may have a larger effect on electric charge compared to particle size alone. The measurements demonstrated that in arid environments, away from coastal locations, sea breeze fronts can generate significant levels of charge, causing surface E-fields as large as -7 kV m-1, which are unaccounted for in radiative transfer and dust source schemes used in climate modeling.
The study investigated and enhanced the understanding of the processes which give rise to dust electrification in complex situations such as dust storms and dust devils, which occur on a sporadic basis. The E-field measurements reported in this work are the first to be made in the UAE and the Arabian Peninsula region.
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