Meet the Team
None of the research in our group would be possible without our great team of students, researchers and engineers. Below is a list of the present students in our group.
Hofit is studying the use of micro-sensors in smartphones for monitoring natural hazards, particularly wildfires. She is using data collected around the globe from the WeatherSignal App.
Yanai is studying superbolts of lightning which are the most powerful lightning flashes on Earth. The easten Med is a hotspot for superbolts, and he is trying to understand why this is.
Shai is studying the possibility to improve high resolution weather forecast models using pressure sensors inside smartphones carried by the public. These data may improve the initial conditions of models.
Judi is studying the topic of hygro-electricity, and possible way of generating renewable energy from humidity in the air. The research may be related to how thunderstorms are electrified.
Aviad is studying the relationship between rainfall and lightning using two independent satellite data sets. The Global Lightning Mapper (GLM) and the Global Precipitation Mission (GPM).
Dekel is studying the link between lightning activity in Israel and flash floods. He is studying the spatial and temporal relationships between rainfall and lightning activity.
Raam is studying the long term trends in thunderstorm activity over Africa and South America using ERA5 data and a model to estimate the number of thunderstorms based on large scale meteorological data.
Tair is studying the link between thunderstorms and upper tropospheric water vapor (UTWV), a strong greenhouse gas. This is a joint Israel-India collaboration, using ELF and VLF lightning data.
Ziv is working on developing a new smartphone App to easily collect environmental data from the public via their phones for use in our research. These data will be used for different research purposes.
Moran is studying how insurance agencies can be convinced to invest in climate change mitigation processes in order to offset their future expenses related to increasing natural disasters related to climate change.
Maayan is studying the relationship between VLF waveforms of lightning and infrasound signals from lightning. The goal is to identify the specific signature of lightning discharges.
Orly is studying the impact of sea level rise resulting from climate change on the coastlines of Israel. Both past trends and future predictions, and the implications on the coastline infrastructures.
Omri is working on the use of pigeons and bats to monitor air pollution in Tel Aviv using micro sensors that can be attached to the animals.
Navot is involved in a joint TAU-Duke University project to study how air pollution results in the deterioration of solar panels used to generate electricity.
Melody is working on a possible early warming system for thunderstorms and lightning in the developing world. This will be based on the Franklin chimes developed by Benjamin Franklin.
Gal was working on the Schumann resonances produced by global lightning in the extremely low frequency (ELF) range. These frequencies are between 5-45 Hz, and we continuously monitor and archive these data at our field sites in Israel. In addition to the lightning fields, it is known that many biological systems, from zooplankton to the human brain, exhibit electrical activity in the same ELF range. Gal is attempting to understand if any links exist between the Schumann resonance fields and biological systems.
Roy was working on problems of fair weather atmospheric electricity. He has helped construct a new field site on Mt. Hermon, with both a vertical electric field meter and vertical conduction current meter. We now have 2 identical stations separated by a few hundred kilometers. In addition, Roy is involved in simultaneous balloon sounding of the fair weather electricity profile from Israel, UK, Spain, Russia and Antarctica. These profiles show the cosmic ray ionization profile of the atmosphere, and the differences that occur with latitude, season, etc. How do solar storms impact these fields at the ground and aloft? What is the local contribution?
David (Shai) was working in the field of infrasound observations and analysis related to atmospheric processes. David was using the Israeli infrasound network to study the signatures of thunderstorms and sprites, as well as the impact of Mt. Etna on the infrasound signals detected here in Israel. We have also gained access to the global CTBTO network of infrasound sensor that we wish to use to study the convection and thunderstorms in tropical Africa that often lead to the formation of hurricanes.
Israel was studying short and long term changes of the upper atmosphere. As the troposphere warms due to global warming, the upper atmosphere is cooling at a much faster rate, resulting in a lowering of the D-region of the ionosphere. Israel is using VLF narrowband methods to study changes in the reflection height of the lower ionopshere, while also using infrared measurements of the OH airglow layer to study changes in the temperature at ~90km altitude above Israel. Is there a link between changes in temperature at the mesopause and changes in the VLF reflection height?
Daria worked on sprite formation on Jupiter, Venus and Saturn. Daria spent her first year working on laboratory experiments of sprites in collaboration with the Dutch group of Ute Ebert. Daria is looking at the structure, spectra and formation of sprites in different atmospheric compositions. Her research points to the likelihood of sprites existing on other planets, especially Jupiter and Saturn.
Yuval will be focusing his studies in the very low frequency (VLF) range, to observe and model the natural and anthropogenic radiation in the atmosphere. VLF radiation is emitteed naturally by lightning discharges, while anthropogenic sources are primarily VLF transmitters used for navigation purposes. These transmitters have known location, output energy and frequency, and hence can be used as a controlled source to study changes in the ionospheric properties due to solar storms, sprites, and other transient events. (Yuval.Reuveni@jpl.nasa.gov)
Adi has continued his MSc work by expanding our investigation into ULF precursors to earthquakes. Adi is establishing a second ULF site close to the Dead Sea, while simultaneously collecting ULF magnetic data and seismic data. In addition to the seismic comparisons, Adi is also studying space weather anomalies in our data, including changes in the ground observations across the terminator (sunrise and sunset).
Eran is working on ELF detection of lightning, with a focus on ELF transient. These transients are produced by intense lightning flashes around the planet, and are also believed to be the trigger for most of the sprites and othe TLEs around the planet. Eran has been looking at ELF statistics from our Mitzpe Ramon ELF site, and contributing to our winter sprite observation campaigns.
Olga developed a new theoretical model of the Schumann resonance, using a combination of two previous models: the partially uniform (day-night earth-ionosphere cavity) model and the "knee" ionospheric conductivity profile model, into the PUK model (partially-uniform knee model). This model is capable of simulated to observed Schumann resonance parameters for a wide range of boundary conditions, including other planets. Olga will be using her model to explain certain features in the observed ELF data, such as the terminator-effect, and the variability in the amplitude, frequency and damping of the Schumann resonance parameters.
Mustafa has investigated the connection between regional lightning activity (using the Schumann resonances) over Africa and various important climate parameters, such as surface temperature, large scale updrafts, and upper tropospheric water vapor. Mustafa has found some remarkable relationships between daily thunderstorm activity in Africa and the moistening of the upper atmosphere a day later. In addtion, he devloped and empirical model to study long term thunderstorm activity over tropical Africa. Mustafa started his PhD research working on the geolocation of sprites using ELF/VLF methods.
Tamir carried out research on the ground level enhancement of gamma rays at the Mt. Hermon cosmic ray observatory. In recent years long term (hours) enhancements of gamma radiation has been observed with ground detectors, and often associated with thunderstorms and stormy weather. There are two hypotheses as to the source of these enhancements in gamma rays. The first is from the high electric fields within the thunderstorms above the station, accelerating charged particles to relativistic speeds. The second is the washout of radon daughters by the rain below the storms. Tamir found that the majority of enhancements are associated with rainfall, but not all.
Uriel carried out research related to Space Weather. This was a joint thesis under the supervision of Dr. Sari Katz (Soreq Nuclear Research Center) as well. The research looked at satellite failures are malfunctions as a result of solar storms. Uriel investigated many different satellite malfunctions, some published in the literature, others not. He developed a empirical model to try to predict the type of damage to satellites based on different types of solar storms.
Maayan was studying the link between thunderstorms and climate change. Using the clustering scheme of Keren Mezuman (above) we were looking at the link between regional temperatures, instabilities, water vapour, etc. and the number, size and intensity of thunderstorm clusters. Will warmer temperatures result in more thunderstorms with the same intensity, less storms but more intense, or more storms that are also more intense? Hopefully Maayan's research will allow us to better understand what may happen in the future to thunderstorms.
Shai was studying the fair weather atmospheric electricity in Israel. We have both conduction current sensors and electric field sensors at our field sites, and Shai will help interpret the data we are collecting. We are interested in understanding the connection between local and global sources of variability in the atmospheric electricity data. Shai is also involved in our winter observations of sprites in Israel (ILAN project).
Ron was working on problems of Big Data using smartphones as sensors. It turns out that today most smartphones have many different micro-sensors that detect and monitor our environment. For example, there are sensors for pressure, magnetic field, gravity, humidity, light, temperature, and more. We are investigating the sensititvity of these sensor to changes in the atmospheric parameters. We have purchased a few smartphones to perform control experiments in order to better understand how we can tap into this huge data source from around the globe.
Alisa was working on problems related to marine stratocumulus (MSC) clouds detected by satellite imagery. This is a project together with Ilan Koren from Weizmann Institute. MSC clouds are low level water clouds normally found above cold ocean currents (west of California, west of Peru) that influence the albedo of our planet. The higher the albedo (reflectivity) of Earth, the cooler it gets. Hence changes in MSC clouds can impact global warming. Alisa has developed a metod to catergorize the cellular structor of these clouds detected in satellite images.
Shay was using the clustering scheme developed by Keren Mezuman (above) to look at patterns of these thunderstorm clusters in hurricanes and tropical storms. We know that hurricanes have electrical activity in their rainbands, but how are these storm clusters related to the tropical storm intensification? It appears that the number of clusters in the hurricane may tell us something about the future state of the storm, with possibilities to improve the forecast of the intensification of these monstor storms.
Gil was studiying the wave propagation of infrasound waves (sub-acoustic) in the atmosphere. These infrasound waves can be produced by many factors, from explosions, to earthquakes, thunderstorms, sea swells, volcanoes, and more. Gil is simulating the propagation of these acoustic waves in the atmosphere, and the transition of the waves from below the Earth's surface into the atmosphere. Since we have already detected the infrasound signatures of sprites in our data, Gil is trying to simulate the propagation path from sprites to our detectors in Israel.
Hofit was studying the possible occurrence of ULF precursors before earthquakes. It has been shown by a number of research groups that ultra low frequency (ULF) magnetic anomalies occur weeks or even months before large earthquakes. Hofit has helped set up a chain of 3 ULF stations along the Dead-Sea Rift valley to monitor the natural ULF fields continuously. She is developing algorithms to monitor the local and regional magnetic activity, with the purpose of trying to detect signals related to seismic activity in our region.
It is always quoted in books at papers that there are ~2000 thunderstorms active at any time around the globe. This was obtained from a simple caluclation made in 1925! Since then nobody has checked this estimate. Keren used global lightning data from the WWLLN network, together with cluster schemes, to count the number of active thunderstorms that exist on our planet. How do the numbers of storms vary as a function of hour, day, month, season, and year? And how well do these clusters match the famoues Carnegie Curve?
Naama worked on the problem of hurricane formation in the Atlantic Ocean. We have recently found some interesting connections between hurricane genesis and electrical activity in these storms. Naama looked at both IR cloud images, and lightning data, over Africa, to see if we can find any additional information about which African Easterly Waves (AEWs) develop into tropical storms, and then hurricanes. She found that the area coverage of cold clouds in West Africa is a good proxy for which waves will develop into hurricanes.
Moriah is studying flash floods across the Mediterranean region using lightning data from the ZEUS network in Greece. This is part of a large EU projet named FLASH to try to better understand and predict flash floods. Moriah is using lightnign data to develop nowcasting algorithms for the coming 3-6 hours.
Roy graduated in 2009. He was in involved in the optical observations of sprites using calibrated cameras. Roy developed a method of using cheap WATEC cameras for obtaining information about the brightness of sprites. He has calibrated our cameras and used the results of our calibrated meausurements to make comparisons with sprite features, such as sprite length, number of elements, etc.
Gil studied under the joint guidance of Prof. Pinhas Alpert and myself. The goal of the thesis was to investigate the role of the artificial Yatir forest in the south of Israel, on the local climate. Does the forest have any regional effects on temperature, humidity, wind, and even precipitation. Due to the size of the Yatir forest, the results showed a very small impact on the local climate outside of the forest.
Gady studied in the Porter School for Environmental Sciences (PSES) under my guidance together with Prof. Yoav Yair from the Open University. Gady studied the link between lightning activity in Israel and urban areas. He looked to see if the spatial distribution of lightning is influenced by the large metropolitan regions of Tel Aviv and Haifa. One interesting find is the mazximum in positive ground flashes detected east of Tel Aviv, while a minimum in lightning was detected over parks within the city.
Shahar is also involved in the flash flood project FLASH, however, focusing on the hydrological aspects of flash floods. We are working together with Efrat Morin of the Hebrew University on this project to simulate past and future flash flood events in Israel and other Mediterranean countries.
Oren studyied the impact of the ENSO cycle on rainfall in the eastern Mediterranean. As a result of some earlier findings showing a positive correlation between ENSO and rainfall in northern Israel, Oren is extending the study, and investigating the physical reasons for these connections.
Michal hunted for sprites, elves and other transient luminous events (TLEs) above winter thunderstorms in Israel. We hope to observe sprites for the first time in the eastern Mediterranean, and during winter thunderstorms. Michal will investigate the type of thunderstorms that are likely to produce sprites in our region.
Adi studied natural electromagnetic signals in the ultra low frequency (ULF) range. A new ULF monitoring site has been set up near Eilat to investigate the possibility that ULF precursors may exist prior to large earthquakes. Such precursors have been observed in other regions of the world. Adi is involved in the ULF data analysis and interpretation.
Bela studied the thunderstorm and lightning patterns over the entire Mediterranean Sea. Using the TRMM satellite with both precipitation radar (PR) and lightning sensors (LIS) she studied the interannual variability of thunderstorms during the winter months, and the relationship between lightning and rainfall.
Eran developed a new Schumann resonance algorithm for globally geo-locating intense lightning flashes around the globe. This discharges most likely trigger the formation of sprites in the upper atmosphere. Eran also used a number of stations to geolocate lightning during the MEIDEX space shuttle mission.
Olga studied the connections between rainfall and lightning activity in winter thunderstorms in Israel. She used a combination of satellite and ground-based measurements to study a few intesnse thunderstorms in Israel. She found a lag of approximately 10 minutes between peak lightning activity and peak rainfall.
Moshe worked on the topic of radio waves produced by incoming meteors. We were involved with the 1999 Leonid meteor shower campaign in Israel, duing which we collected ELF/VLF data continuously. We have found clear electromagnetic pulses produced by the incoming meteors.
Mustafa worked on the topic of sprites, and the detection of the extremely low frequency (ELF) electromagnetic radiation emitted by the lightning that produces the sprite. Optical observations of sprites by Dr. Walt Lyons in Colorado were compared with the ELF measurements in Israel.
Ephrat finished her Masters degree in 1999. She worked on a project dealing with Water Balance in the Middle East. She attempted to look at how the water balance (effective precipitation= P-Ep) has changed over the last 50 years in the Middle East based on observational data.