New research of PhD Student: Roy Yaniv, Advisors: Prof. Colin Price and Prof. Yoav Yair
The global electric circuit (GEC) on earth is driven by electrified shower clouds and thunderstorms. The current flows up to the ionosphere from severe weather regions and returns back to earth in areas known as fair weather regions. The vertical conduction current density (Jz) is of typical value of ~1-2 pA m-2. The vertical electrical field (Ez) is of typical value between 100-300 V/m near ground and correlates with the diurnal thunderstorm activity - known to be the Carnegie curve.
We built 2 measurement stations in Mizpe Ramon and Mount Hermon to measure the parameters of the GEC. 2 conducting plates to measure the conduction and displacement currents. The second station is a rotating Electric field meter (Campbell Scientific).
The diurnal changes of the vertical E-field (Ez) in fair weather days in Mitzpe Ramon were found to correlate with the Carnegie curve and are influenced by the morning heating of the sun that lift aerosols and increase the Ez. The results in the Hermon found a greater morning increase as a results from the uplift of a charged aerosol layer to the mountain top in the morning hours in what known as "Austausch". The layer is charged overnight in the surrounded valleys when the inversion is low in what known as the "electrode effect".
The fair weather data is used for future studies on the impact of solar storm on the global circuit. We want to study the impacts of daily local changes on the global circuit parameters.
Mean diurnal fair weather behavior of the vertical electric field in Israel
Hurricanes are the most damaging and most massive storms on Earth. They cause huge economic damages, while killing thousands of people every year. While the forecasts of the direction of motion of hurricanes is fairly well predicted, the forecasts of the intensity of the storms in the future is not well predicted. We are working on ways to better improve the forecasts of hurricane intensity in the coming 24-48 hours. In the Atlantic Ocean most of these tropical storms start off as clusters of thunderstorms over Africa. We are looking at the cloud cover and lightning activity over Africa to better understand which clusters will eventually develop into hurricanes.
In addition, we are using lightning data within hurricanes to better understand the development of these monster storms. We have found that the electrical activity within the hurricanes reaches a peak 30 hours BEFORE the maximum sustained winds in the eye of the hurricane. This research has been conducted over the years with graduate students Mustafa Asfur, Naama Reicher and Shay Frenkel.
Researcher: Roy Yaniv
Advisors: Prof. Colin Price and Prof. Yoav Yair
The Earth's atmosphere can be described as a huge global electric circuit (GEC). The batteries of the electric circuit are the ~1500 thunderstorms active around the globe at any time. Each storm produces about 1 Ampere of current that flows up to the ionosphere and returns back to Earth in areas known as fair weather regions, like the Negev Desert. The vertical conduction current density (Jz) measured at the surface in fair weather regions is of typical value of ~1-2 pA m-2. In addition, the ionosphere and the Earth's surface act like a huge spherical capacitor, with a voltage of 250kV between the ionosphere and the Earth. Near the surface, the vertical electrical field (Ez) is of typical value between 100-300 V/m and correlates with the global diurnal thunderstorm activity - known to be the Carnegie curve.
We have built 2 measurement stations in Mizpe Ramon and Mount Hermon to measure the parameters of the GEC. For the Jz we have two conducting plates that measure the conduction and displacement currents (see figure below, right). The second sensor (below, left) is a rotating Electric field meter (Campbell Scientific) used to monitor the changes atmospheric electric field.
The diurnal changes of the vertical E-field (Ez) in fair weather days are found to correlate with the global Carnegie curve, but are also influenced by the morning heating of the sun that lifts aerosols into the air and increases the Ez values. We are studying the local and global impacts on the GEC variability, as well as how solar storms impact the GEC.