atmosphere along the propagation paths of dust storms generated during an intense wind erosion of soils are
studied experimentally in the semideserts of Tajikistan, California (the United States), and Kalmykia. The field
polarity was first observed to vary from positive values E(X) = 100–400 V/cm at the distance from the dust
source X = 2–8 km to negative values E(X) = 100–200 V/cm at X = 30–80 km. The passage through zero, i.e.,
the change in the field polarity, occurs most frequently at a distance of 9–12 km. The global background values
E=+(1–2) V/cm are restored as the stream reaches distances X > 100–120 km. The complex behavior of vari-
ations in E(X) is explained by the contact electrification of the surface erosion products of loess-like soils during
the saltation of sand particles (with diameters D = 80–200
m). Large particles in the stream (D > 1 m) pre-dominantly acquire positive charges, whereas the small-size fractions of dust (D < 0.3
m) acquire negative charges. The sedimentation of coarse-dispersed particles in the stream is completed at the distance X = 10–20 km,
which leads to the change in the field polarity. In the context of the model proposed, the general gradual
decrease in E(X) is explained by turbulent diffusion and background atmospheric ionization.