Ground based measurements of Fair and Disturbed weather electric field in southern Israel

Abstract:

The Earth's fair weather vertical electric field (Ez), or surface potential gradient, is one of the key parameters used to investigate the Earth's Global Electrical Circuit (GEC). Past fair weather measurements conducted over the oceans (The Carnegie curve) show a diurnal variation that correlates positively with the diurnal variation of global thunderstorm activity. However, during local dust storms with high concentrations of aerosols, the atmospheric conductivity is reduced significantly, and a marked increase in the Ez is expected.

Ground-based measurements of Ez have been performed from June 2013 at the Wise Observatory in the Negev desert, a quiet and remote station in southern Israel (30⁰35’N, 34⁰45’E). The measurements aim to study the diurnal and seasonal behavior of Ez , separating local and global impacts. The global impact is associated with global thunderstorm activity while the local impact is found to depend on the synoptic regime that governs the amount of aerosol loading. In several extreme dust events in Israel, we observed increases in the electric field that coincided with the presence of PM10 particles, in concentrations of 300-1000 µg/m³. The prevailing meteorological conditions in fair and disturbed weather events will be discussed.