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 (Ez) 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 Ez and J values fluctuating between − 460 and + 570 V m− 1 and − 14.5 and + 18 pA m− 2 respectively. In contrast, the Ez 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.
Bibliographical noteFunding Information:
This research is supported by the Israel Science Foundation (ISF) for financial support through Grant No. 423/14 . We thank the AeroNet Sde-Boker team and the Ministry of Environmental Defense for letting us use their data. We are grateful to David Shtivelman from Tel-Aviv University for his helpful technical support for the ground instruments and to Oren Davidoff from the Israeli Meteorological Service (IMS) for grammatical edit of this manuscript. We thank the Wide Lightning Location Network ( http://wwlln.net ), a collaboration among over 50 universities and institutions, for providing the lightning location data used in this paper.
© 2017 Elsevier B.V.