Research interests encompass the fundamentals of atmospheric and oceanic dynamics. The complex whirling of eddies of all sizes, the majestic major ocean currents or jet streams in the atmosphere are all examples of large scale dynamical features of the ever evolving fluids that move on the surface of the rotating spherical earth. The amount of fluid (be it gas in the atmosphere or saline water in the ocean) that are transported by these flows is too large for us to grasp at first glance. The Gulf Stream transports about 100 million tons of water every second from low latitudes to the mid-latitudes along the eastern coast of North America; about 3,000 times the amount of water flowing down the Niagara Falls. The Subtropical Jet Stream in the atmosphere transports about half-a-million tons of air (recall that the density of air is about 1/1000 that of water) around the earth from west to east at altitudes of about 10 km and speeds of the order of 100-150 km/h. The existence of the Subtropical Jet Stream enables the Israeli Airline El-Al to fly non-stop from Los-Angeles to Tel-Aviv, which it does in the opposite direction quite seldom. In my Geophysical Fluid Dynamics (GFD) research I attempt to define the exact physical origin of certain fluid dynamical phenomena and to provide exact theoretical descriptions of their observed features (such as the way they change with time and space). I also attempt to highlight the geophysical ramifications of their presence. 

In recent years I developed a theory of non-harmonic (also described as Trapped) waves of Geophysical Fluid Dynamics based on the formulation of a time-independent, Schrodinger eigenvalue equation for zonally propagating wave of the Rotating Shallow Water Equations (AKA Laplace Tidal Equations). The energy levels of the eigenvalue equation provide explicit expressions for the phase speeds of the waves and the associated eigenfunctions describe the meridional amplitude structure of the various waves. This formulation is relevant to many physical settings including the mid-latitude f-/β−β− plane, the equatorial β−β−plane and the spherical Earth. In particular, this formulation provided, for the first time, explicit expressions for the dispersion relations of Planetary (Rossby) waves and Inertia-Gravity (Poincare) waves on the spherical Earth (i.e. a rotating sphere but without the centrifugal acceleration. In additon to providing approximate, but highly accurate expressions for Planetary and Inertia-Gravity waves on the spherical earth the formulation of the Schrodinger eigenvalue equation has provided a clear demonstration that Yanai wave (AKA the mixed Rossby-Gravity mode) exists on a sphere but for different reasons than on the equatorial β−β−plane: In the latter this wave exists only because the second westward propagating wave is associated with singular zonal velocity while on a sphere the approximate solution by the Schrodinger equation yields an unacceptable (complex) phase speed near the gravity wave phase speed.

In contrast to the planar theories where Kelvin waves exist as additional modes to Inertia-Gravity waves (e.g. modes in which one velocity component vanishes identically so the other velocity and the height fields solve the three scalar Rotating Shallow water Equations) on a sphere these waves do not exist at all but the eastward propagating Inertia-Gravity n=0 mode is nearly non-dispersive.                

These theoretical advances enabled the construction of test cases for the dynamical cores of global scale General Circulation Models and the explicit expressions have also been applied in the interpretation of satellite borne observations of Sea Surface Height Anomalies in the Indian Ocean south of Australia where the nearly zonal coast provides the "wall" at which the waves are Trapped. 

My book entitled “Shallow Water Waves on the Rotating Earth” which was published by Springer in 2015 provides the details of this unified approach to the known waves of Geophysical Fluid Dynamics.

Extensions of classical Geophysical Fluid Dynamics theoriest to more complex/realistic set up, e.g. from the f-plane to the ββ-plane (or the sphere) or to bounded domain instead of an infinite one, also include Stommel (1948) fundamental wind-driven ocean gyres theory to a meridionally narrow domain and Ekman (1905)'s wind-driven surface transport in the ocean to the ββ-plane and to the spherical Earth. The first of these advances explains why there is no western boundary current in the South Pacific Ocean. The reason that emrges from the new theory is that compared to the other oceans, this ocean is narrow meridionally and long zonally. The second theory provides direct estimates of the zonal drift that columns of water undergo when the Coriolis frequency varies with latitude. The figure below, taken from the article published in January of 2023 in Ocean Science, shows how the zonal drift is insensitive to the sign of the wind stress indicated by the sign of ΓΓ (i.e. whether the wind blow eastwards or westwards) and that for sufficiently weak wind stress (right panel) the drift is directed westward (as in inertial oscillation) whereas for sufficiently high stress (left panel) the drift can reverse its direction.   
Similar results also hold on the spherical Earth.

Research Students

Roby Harcz (MSc Student)

Itamar Yacoby (PhD Student)

Contact Information

Nathan Paldor | Room 313 North | 972-2-65-84924 | nathan.paldor@mail.huji.ac.il

 

Research Interests: The questions that drive my research are understanding man-made impacts on cloud composition, precipitation, Earth energy budget and the implications to the climate variability and change. This is done by a combination of in-situ measurements with cloud physics aircraft campaigns into clouds around the world and remote sensing with radars and satellites, including the design of new dedicated space missions. All these observations are integrated and interpreted by model simulations of cloud aerosol interactions.

Research Students

Avichay Efraim (PhD Student)

Guy Pulik (PhD Student)

Contact Information 

 

Daniel Rosenfeld | Room 313 North | daniel.rosenfeld@mail.huji.ac.il

 

Earthquake geology and mechanics, mid-ocean ridge and ophiolite dynamics, geo-archaeology, sea-level change and glaciation.

Research Students 

Erez Hassul (PhD Student)

Eshly Aizenshtat (PhD Student)

Shaked Engelberg (PhD Student)

Oksana Piatibratov (PhD Student)

Nuphar Gedulter (PhD Student)

Noga Rozen (MSc Student)

Anna Visloboko (MSc Student)

Contact Information 

 

Amotz Agnon | Room 216 South | 972-2-65-84743 | amotz@mail.huji.ac.il

 

1. Biomineralization in foraminifera and corals: Physiology, cellular mechanisms and their implications for paleoceanographic interpretations.
2. Marine aspects of the global carbon cycle, particularly photosynthesis and calcification in corals and foraminifera in view of ocean acidification.
3. Biogeochemistry of stable carbon isotopes in marine and aquatic systems.
4. Development of new tools for paleoceanography and paleolimnology using stable isotopes and trace elements.
5. Carbon and nutrient cycling in coral reefs in view of global change.

Research Students 

Adam Levi (PhD Student)

Sharon Ram (PhD Student)

Contact Information

Jonathan Erez | jonathan.erez@mail.huji.ac.il | 972-2-65-84882

The research straddles the interface between zoological, geological, and humanistic studies in that it focuses on faunal remains as paleoenvironmental indicators of past human societies. Within this broad discipline, we are involved in the study of fauna from Pleistocene sites ranging in time from nearly two million years ago to the Holocene. The scope of our research encompasses the paleoecologic, taphonomic and taxonomic implications of faunal assemblages from Pleistocene sites in the southern Levant.

Together with colleagues, we guide students from archaeology and from geology as they induce new fields of study, such as virtual paleontology; research on hitherto unknown faunal records from Mongolia; applying 3D models for the interpretation of Neanderthal faunal exploitation patterns, and even the use of Ichnotaxa as a tool for reconstruction of the paleoenvironment. 

Gali Beiner, is the conservator of the National Natural History Collections and she is also leading research into better conservation protocols in the lab and in the field.

Research Methods

Our research uses morphological observation with quantitative methods, microscopes and CT. We use the following collections as source of comparison and research.

The Archaeozoological collections comprise hundreds of sites representing the history of the fauna from the Pliocene to the Holocene of Israel, where major events in the history of human took place, from hunting, gathering, fishing, to domestication and husbandry. The collections are open to students and researchers from all over the world.

The recent vertebrate comparative collection represents the local fauna of Israel and adjacent regions. It includes specimens of all taxa collected during the past 60 years. This collection represents populations from various regions of the country. Prof. Israel Aharoni started the collection at the beginning of the 20th century, and was in turn followed by researchers and students who collected animals for research and teaching. Rare species, extinct species, and endangered species, including type specimens, are present in the collection. 

The Paleontological collections hold an impressive body of information on the fossil records of the eastern Mediterranean, its biogeographic origins and the evolution of invertebrates and vertebrates.

 We enlarge these collections through the research of our groups including survey and excavations.

Research Students 

Steiner, T. Doctoral student (with Prof. G. Shelah HUJI). 

Jallon. A., Doctoral student (with Prof. E. Hovers, HUJI)

Nikolskaia, P. Doctoral student

Frish, A. MA. students (with Prof. Y. Garfinkel HUJI).

Friedman, R. MSc. student (with Drs. A. Muskin and R. Calvo, Geological Survey Israel). 

 

Contact Information 

Rivka Rabinovich | rivkar@mail.huji.ac.il | Giveat Ram, Berman building, Floor -1 | Institute of Earth Sciences, south wing, Floor 0, room 12. 

Gali Beiner - Lab Manager | gali.beiner@mail.huji.ac.il

Our research focuses on the signal transfer between the modern atmosphere and oceans to the geological record, the impact of abrupt events on primary and export production in the oceans, trace element cycles, and reconstruction of Quaternary paleoclimate from lacustrine and marine archives. We combine between time series of modern marine and terrigenous particulate fluxes, coeval seawater compositions, and biogeochemical cycles in the oceans (see the REDMAST project).

Research Studants

Dr. Clara Flintrop - postdoc

Gil Lapid - Ph.D. Student

Noy Levy - Ph.D. Student (Supervised jointly with Dr. Ralf Schiebel from Max Planck Institute for Chemistry, Mainz, Germany)

Efraim Brill - M.Sc. Student

Aden Clarfield - M.Sc. Student

Lea Sivan - M.Sc. Student

Contact Information

Adi Torfstein | adi.torf@mail.huji.ac.il

Lab Manager - Sigalit Amiran-Kan

Our research group focuses on the recycling of volatiles such as carbon and hydrogen from the surface to the deep Earth and their relation to the evolution of oceanic and continental crust through time.  We combine petrologic, geochemical, and spectroscopic work to study the igneous samples that cover the spectrum of mantle compositional ‘flavors’, as monitors of deep Earth processes.

In particular, we work with diamonds and specialize in the analyses of their microinclusions. Such inclusions contain the most pristine samples of deep carbon- and water-rich (C-O-H) mantle fluids. Their high volatile content, strong enrichment in incompatible elements, and possible relation to subduction processes, make them a key player in the global circulation of volatiles. They elucidate the origin of various types of deep mantle fluids, the relationship between them and their host diamonds, and the metasomatic processes that led to their formation. 

The long-term intent is to remedy the full spectrum of deep mantle carbon- and water-rich (C-O-H) fluids, provide a first-order understanding of the role of such fluids in transporting volatiles and incompatible elements between mantle and crustal reservoirs, and link tectonic events in the shallow continental crust and chemical events involving C-O-H fluids in the deep mantle.

Research Methods

We combine petrographic, geochemical and spectroscopic work using various analytical capabilities including LA-ICP-MS, EPMA, TEM, TIMS and Raman and infrared spectroscopy, to study the minerals and fluids trapped in diamonds and the composition of igneous magmas.

Research Studants

Yael Kempe (PhD student)

Sharon Viater (MSc student)

Miriam Sokol (MSc student)

 Pazi Shacham (volunteer)

Contact Information

Yaakov Weiss | yakov.weiss@mail.huji.ac.il

Lab Manager - Ofir Tirosh | ofirtirosh@gmail.com

 

Research interests

The Earth’s radiation budget and future climate change are intricately linked to clouds and aerosols. Efforts to accurately predict future climate, and socially adopt to it, are hampered by our limited understanding of how aerosols, clouds, circulation and climate interact. My main research interest is in trying to better understand the role of clouds and aerosols in the climate system. In order to do so I mostly use numerical models of different scales (from the single cloud scale to the global scale). Today’s state-of-the-art climate models, which are the main tool for predicting climate change, cannot work with the sufficient resolution required to directly solve the relevant physical processes related to clouds. This inability hampers our efforts to account for the clouds’ role in climate change and to predict future climate. On the other hand, high-resolution, limited-area, cloud resolving simulations are unable to directly account for the changes in the dynamics and thermodynamics of the climate system, hence they lack an important component of the clouds response. I believe that cerfully combining these tools (limited-area high resolution simulations and global simulations) together with observations is the preferred way to improve our understanding.    

Research Studants 

Dr. Namrah Habib - Postdoc (co-hosted with Nathan Steiger)

Dr. Jacob (Koby) Shpund - Senior Postdoc

Sreelekshmi T.- PhD student

Gedaliya Kitrossky - M.Sc. student (Co-supervised with Danny Rosenfeld)

Yuval Levin - M.Sc. student (Co-supervised with Assaf Hocman)

Suf Lorian - M.Sc. student

Denis Shum- M.Sc. student

Netta Yeheskel- M.Sc. student

 

Contact Information

Guy Dgan | guy.dagan@mail.huji.ac.il 

 

The research group focuses on the relationship between processes occurring at the earthquake source, ground vibrations, and the damage they cause, as well as analyzing ground noise from various sources. The group covers diverse research directions, including developing methods for assessing earthquake damage and early warning, understanding parameters controlling the earthquake source and magnitude, and using spatial seismic noise to understand subsurface structure and geology. The research utilizes earthquake data recorded through seismometers, accelerometers, and optical fibers using Distributed Acoustic Sensing (DAS). Optical fibers allow for extremely high-resolution ground vibration measurements in time and space, enabling a deeper understanding of seismic waves, earthquake sources, and the subsurface structure through which these waves pass.

The group collaborates with external companies such as Prisma Photonics and Mekorot Water Company to perform earthquake measurements using various optical fibers deployed in Israel. Additionally, some research is conducted in collaboration with researchers from other universities and the Geological Survey of Israel.

The work in the group involves seismic data analysis in time and space, developing various mathematical models and adapting them to observations, and field data collection.

Research Methods

• Analyzing seismic data, time and space series, and extracting significant parameters from the data.

• Developing theoretical, empirical, and statistical models.

• Developing algorithms for real-time seismic data analysis as part of earthquake warning system development.

• Analyzing seismic noise through correlations and inversion methods to develop models describing subsurface structure.

• Big data analysis using computer clusters

Research Students

Shahar Ben Zeev (Post-doc) 

Matty Sharon (PhD Student) 

Gil Noy (MSc Student) 

Linoy Greenberg  (MSc Student) 

Avinoam Hershler  (MSc Student) 

Contact Information

Itzhak Lior | itzhak.lior@mail.huji.ac.il | Room 14 South 

 

Research in the lab:

(a) We develop and utilize theoretical models that describe the interaction of radiation with particles in Earth's atmosphere and oceans. We are particularly interested in how best to model the effects of irregular particles, such as non-spherical particles, porous particles, particles comprised of disordered/amorphous materials, particles comprised of optically anisotropic materials, and mixtures of different components in the same particle. We simulate both single-scattering and multiple-scattering of unpolarized and polarized radiation. Our calculations have implications for modeling global climate and for remote sensing.

(b) We investigate discharges of lightning and transient luminous events (TLEs), such as sprites, which occur above thunderstorm clouds. We analyze lightning and sprite observations, and we develop theoretical models to help explain some observed phenomena, such as the circular configuration of simultaneous sprites and the shift in the location of sprites from their parent lightning event.

(c) We participate in collaborative efforts to monitor light pollution caused by artificial nighttime light and to simulate its propagation in air and in water, with implications for various ecosystems.

Research Method

We build theoretical models and run simulations both on local computers and on larger computer clusters. We analyze observations using various statistical tools, including some machine learning tools.

 

Research Studants 

 

Ynon Hefets (doctoral student)

Guy Pulik (doctoral student, co-supervised by Daniel Rosenfeld)

Gili Kurtser-Gilead (master’s student)

Roby Harcz (master’s student, co-supervised by Nathan Paldor)

David Walk (master’s student, co-supervised by Yoav Yair, Reichman University)

Camille Labrousse (postdoc, co-supervised by Noam Levin, Department of Geography)

 

Contact Information

Carynelisa Haspel  | room 302N | phone +972-542122328  | email: carynelisa.haspel@mail.huji.ac.il

My research aims at extending the duration of reliable weather forecasts, and to then explore how the dynamical processes that are important on these short timescales may manifest on longer, climate-change timescales. The traditional approach to weather forecasting on one- to two-week timescales utilizes weather forecasting models, but on timescales longer than two weeks, the value of deterministic (or ensemble-based probabilistic) forecasts weakens. This is due to the presence of chaotic variability in the atmosphere. Yet certain modes of variability in the climate system have timescales longer than this two-week threshold, and the key to longer-scale prediction is to take advantage of these modes. By understanding the impacts of these modes of variability on surface weather, the potential for improved forecasts on a monthly timescale can be demonstrated and eventually realized. As many of these processes may be modified under climate change (or alternately, climate change may project onto these climate modes), a better understanding of these modes can also help improve the quality of climate change projections.

Two such classes of modes of variability are stratospheric variability (both in the tropical and polar stratosphere) and tropical tropospheric variability (e.g. the Madden-Julian Oscillation and El Nino), and most of my ongoing research focuses on these phenomena. For example, both polar stratospheric sudden warmings and the Madden-Julian Oscillation have been shown to influence European and Mediterranean weather, but it is unclear (1) what mechanism(s) underlie these connections, (2) how far in advance the  impacts can be predicted, and (3) what governs the magnitude of the surface impact.  As these processes must be represented by climate and weather models in order to actualize the potential improvement in predictability, and because the observational record of key meteorological quantities is relatively short, I also run models (both idealized and comprehensive) in order to test model fidelity and to isolate key processes. The ultimate goal is to improve the predictions and projections of surface weather and climate.

Research Methods

The main research methods are the development and application of models of the general circulation of the atmosphere; analysis of reanalysis data and output from comprehensive climate and forecasting models.

Research Studants 

Wuhan Ning(post-doc)
Yaron Eshet (PhD)
Chen Schwartz (PhD)
 Hagar Bartana (masters)
Benny Keller (masters)
 Gayathridevi  Salila** (PhD, with Dorita Rostkier-Edelstein)
Andre Klif** (PhD, with Assaf Hochman)
Yaniv Goldschmidt (MSc, with Francesco Marra)
Ran Galun (MSc in Computer Sciences, with Ami Wiesel)

Contact Information

Haim Gurfinke | chaim.garfinkel@mail.huji.ac.il

Our group focuses on the relationship between water and extreme weather events in regions characterised by scarcity of water as well as the impact of climate change on such interactions. The research lies at the boundary between hydrology, climatology, atmospheric sciences, and surface processes in environments ranging from vast barren deserts to Mediterranean catchments.

Research Methods

The interdisciplinary research we do combines the development of new tools, data analysis and collection, and modelling of climatic- and hydrologic-related phenomena.

 

Research Students

• Atul Rai; PhD student, School of Earth, Atmospheric and Life Sciences, University of Wollongong. Co-supervised by Tim Cohen. Thesis title: Australia’s inland hydrology: quantifying discharge characteristics of the Lake Eyre basin and Australia’s channel country

• Miku Nakamura; MSc student, the Institute for Atmospheric and Climate Science, ETH Zurich. Co-supervised by Iris Thurnherr. Thesis title: Meteorological factors involved in heavy precipitation in and filling of Kati-Thanda Lake Eyre.

• Guorong Ling; MSc student in the Institute for Atmospheric and Climate Science, ETH Zurich. Co-supervised by Hilla Afargan-Gerstman. Thesis title: Forecasting cyclones related to heavy precipitation events in the Sahara.

 

Contact Information 

Moshe (Koko) Armon | moshe.armon@mail.huji.ac.il

 

In our lab, we study physical processes in the ocean, with a focus on understanding both past and present climate changes and the interaction between the sea and the atmosphere. We conduct ocean measurements, including currents, temperature, salinity, oxygen, and more, using a wide range of instruments such as underwater gliders, current meters, drifting buoys, and surface current radars. Additionally, we run numerical models with varying levels of complexitys. 

 

Surface drifters

 

 

 

Ocean mooring

 

HF radar for surface
current measurements

 

Deploying Acoustic Doppler
Current Profiler

 

Ocean gliders

 

WireWalker

Research Studants: 

Stefan Graf (PhD. Studant)

Itamar Yacoby (PhD. Studant)

Aviram Ohayon (MSc. Studant)

Contact Information:

Hezi Gildor | Room 312 North | 972-2-6584393 | hezi.gildor@mail.huji.ac.il

My research involves the application of trace-element ratios and Sr, Nd, Pb, Mo and Fe isotopic compositions to follow the fate of metals in the environment, in archaeological artifacts and in humans. The clean lab and our sensitive analytical instruments enable me and my students to study small-samples and/or materials with low elemental concentrations (e.g., dust samples, teeth and brain). Currently, my group is involved in research projects centering around:

1. Records of aeolian, fluvial and lacustrine sediments as tracers of paleo-environment conditions and sediment sources.
2. Tracing metal artifacts in antiquity.
3. The dark side of ancient metallurgy: Measuring toxic metals and metallic isotopes (and aDNA) in human populations and in artifacts to trace the impact of early industries through time.
4.  The association between elemental anomalies in the human brain and mental diseases.

We carry out these projects in collaboration with researchers from the Hebrew University (Earth Science, Archaeology, Medicine), the Geological Survey of Israel, Israel Oceanographic and Limnological Research, The Israel Antiquities Authority, Tel Aviv University, Haifa University, GFZ - Potsdam, Germany, Columbia University, University of California San Diego, University of Michigan, and the Institute of Geology and Geophysics, Chinese Academy of Sciences. 

Research Studants: 

Yafit Schnell Ben-Avraham (PhD. Studant)

Sharon Ram (PhD. Studant)

Contact Information:

yigal.erel@mail.huji.ac.il

Our research examines the processes shaping modern surface environments and investigates Quaternary terrestrial changes influenced by hydro-meteorological and climatic variations. We focus on landscape formation across diverse temporal and spatial scales, including slopes, fluvial systems, lakes, coastal areas, soils, and dust. A key emphasis is on quantifying and modeling the changes that occurred during the Quaternary period. Our approach integrates Quaternary sediment stratigraphy, sedimentological tools, and the study of sediment transport over both short and long timeframes, with particular attention to extreme events. Palaeohydrology of lakes and rivers has been a consistent theme in our research over the years.

Our work establishes critical links between climate, hydrology, pedology, active tectonics, and the processes of dust and loess creation, deposition, and accumulation—primarily in arid-desert regions, their margins, and Mediterranean and monsoon areas. A significant focus of our research is on climate change in the world's deserts, often in collaboration with other experts. The rapidly declining water levels of the Dead Sea and its associated salt deposits serve as a "natural laboratory" for many of our studies.

Research Methods:

Our research heavily relies on extensive fieldwork and observations, involving the quantification of processes through measurements, sedimentological characterization, and landscape modeling. We collaborate closely with hydrogeologists and experts in sediments, soils, and limnology. Field mapping and topographic data at various resolutions are fundamental to our research, with GIS and remote sensing techniques being essential tools for our investigations.

Research Studants: 

Haggai Eyal (PhD. Studant) 

Guy Tau (PhD. Studant) 

Maayan Harel (PhD. Studant) 

Contact Information:

yehouda.enzel@mail.huji.ac.il