The role of the atmospheric electric field in the dust‐lifting process

Abstract

Mineral dust particles represent the most abundant component of atmospheric aerosol in terms of dry mass. They play a key role in climate and climate change, so the study of their emission processes is of utmost importance. Measurements of dust emission into the atmosphere are scarce, so that the dust load is generally estimated using models. It is known that the emission process can generate strong atmospheric electric fields. Starting from the data we acquired in the Sahara desert, here, we show for the first time that depending on the relative humidity conditions, electric fields contribute to increase up to a factor of 10 the amount of particles emitted into the atmosphere. This means that electrical forces and humidity are critical quantities in the dust emission process and should be taken into account in climate and circulation models to obtain more realistic estimations of the dust load in the atmosphere.

Applications of Electrified Dust and Dust Devil Electrodynamics to Martian Atmospheric Electricity

“…5) suggest that an electron avalanche and collisional plasma can be created when dust storm E-fields stress the low pressure CO 2 gas. (3) Measurements in terrestrial desert environments reveal that dust devils and dust features can generate large electric fields (Freier 1960;Crozier 1964;Renno et al 2004;Jackson and Farrell 2006;Seran et al 2013;Esposito et al 2015Esposito et al , 2016. If this same electrical generator process occurred in a lower pressure atmosphere (like that at Mars), there would be the initiation of enhanced electron impact ionization and atmospheric breakdown.…”

“…Taken together, all these observations suggest there are complex mechanisms underlying natural dust electrification, and that different effects should be expected in different regions on Earth and Mars. Esposito et al (2016). The slope of the linear trend increases when relative humidity exceeds a critical value.…”

“…9). (Esposito et al 2016) The relation between humidity and particle charging mentioned in Sect. 3.4 was observed by Esposito et al (2016) during dust storms monitored in the Sahara desert.…”

“…(Esposito et al 2016) The relation between humidity and particle charging mentioned in Sect. 3.4 was observed by Esposito et al (2016) during dust storms monitored in the Sahara desert. By a statistical analysis of the data, they found a linear relationship between the concentration of dust entered in suspension and atmospheric electric field.…”

“…Very recently, Esposito et al (2016) carried out several measurements in the West Sahara (Merzouga region, Morocco) during the dust storm season in 2013 and 2014. They performed simultaneous measurements of atmospheric electric field, using a Campbell CS110 field mill, mounted at 2 m and directed toward the surface, atmospheric dust abundance and size distribution (in the range 0.265-34 µm), sand saltation rate (with the Sensit sensors), wind speed and direction at six different heights, air and soil temperature, pressure, relative humidity, soil moisture content and solar irradiance.…”