Electrical properties of the 8–12th September, 2015 massive dust outbreak over the Levant

We report new electrical measurements conducted during the massive dust outbreak that occurred over the Levant in September 08–12, 2015. That event was one of the strongest dust storms on record and engulfed the entire region for 5 consecutive days, over Iraq through Syria, Jordan, Israel, Lebanon, Cyprus and Egypt. At its peak, Aerosol Optical Thickness of 4.0 was measured in southern Israel. Ground-based measurements of the electrical field (E_z) and current density (J) were conducted at the Wise Observatory (WO) in Mizpe-Ramon (30°35′N, 34°45′E) and near the top of Mt. Hermon (30°24′N, 35°51′E). During the dust outbreak very large fluctuations in the electrical parameters were measured at both stations, with remarkable differences between the two locations. While at the Mt. Hermon station we registered positive values of the electric field and total current density, the values registered at the Wise Observatory were significantly smaller and more negative. The Mt. Hermon site showed E_z and J values fluctuating between − 460 and + 570 V m^{− 1} and − 14.5 and + 18 pA m^{− 2} respectively. In contrast, the E_z values registered at WO varied between − 430 and + 10 V m^{− 1}, and the current density fluctuated between − 6 and + 3 pA m^{− 2}. We show that the unique generation and evolution of this dust outbreak gave rise to a significantly different charge structure compared with that observed in short lived convective events, and suggest a tentative explanation for the obtained results.