Ori Adam

Ori Adam
Hebrew University of Jerusalem | HUJI · Fredy and Nadine Herrmann Institute of Earth Sciences

Dr.

About

46
Publications
7,127
Reads
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710
Citations
Introduction
Interested in climate dynamics, with an emphasis on tropical dynamics. Current research questions: -- How monsoons change with climate -- The role of ocean heat fluxes on the seasonal cycle of the tropical circulation -- Energetic constraints on the position of the ITCZ and the tropical circulation
Additional affiliations
September 2016 - present
Hebrew University of Jerusalem
Position
  • Professor (Associate)
February 2013 - present
ETH Zurich
Position
  • PostDoc Position
Description
  • Climate Dynamics
February 2011 - February 2013
Tel Aviv University
Position
  • PostDoc Position

Publications

Publications (46)
Article
Full-text available
End of century projections from Coupled Model Intercomparison Project (CMIP) models show a decrease in precipitation over subtropical oceans that often extends into surrounding land areas, but with substantial intermodel spread. Changes in precipitation are controlled by both thermodynamical and dynamical processes, though the importance of these p...
Article
Full-text available
Heavy precipitation events (HPEs) can lead to deadly and costly natural disasters and are critical to the hydrological budget in regions where rainfall variability is high and water resources depend on individual storms. Thus, reliable projections of such events in the future are needed. To provide high‐resolution projections under the RCP8.5 scena...
Article
Energetic constraints on the time-dependent response of the intertropical convergence zone (ITCZ) to volcanic eruptions are analyzed using the Community Earth System Model Last Millennium Ensemble project. The energetic constraints are found to vary during the first few years, governed by conjoined variations of the energy budgets of the stratosphe...
Preprint
Full-text available
Heavy precipitation events (HPEs) can lead to deadly and costly natural disasters and are critical to the hydrological budget in regions where rainfall variability is high and water resources depend on individual storms. Thus, reliable projections of such events in the future are needed. To provide high-resolution projections under the RCP8.5 scena...
Article
Full-text available
Plain Language Summary In this study we find an error common to nearly all comprehensive climate models used over the past decade: the depth of the tropical south Pacific thermocline is significantly shallower than in reality. The thermocline is the layer that separates the warm upper ocean from its cold depths. When the thermocline is shallower, t...
Article
Full-text available
A recent study observed the existence of a salient bias towards the symmetric part of the tropical wavenumber-frequency spectrum. Examination of the tropical Brightness Temperature (BT) spectrum in this note shows that its parity difference, i.e., the difference between its symmetric and anti-symmetric components, is concentrated in regions of the...
Article
Full-text available
A moist General Circulation Model is used to investigate the forcing of the Asian monsoon and the associated upper level anticyclone by land‐sea contrast, net horizontal oceanic heat transport, and topography. The monsoonal pattern is not simply the linear additive sum of the response to each forcing; only when all three forcings are included simul...
Article
Full-text available
Projections of extreme precipitation based on modern climate models suffer from large uncertainties. Specifically, unresolved physics and natural variability limit the ability of climate models to provide actionable information on impacts and risks at the regional, watershed and city scales relevant for practical applications. Here we show that the...
Article
Full-text available
Background Current techniques for measuring absolute lung volumes rely on bulky and expensive equipment, and are complicated to use for the operator and the patient. A novel method for measurement of absolute lung volumes, the minibox method, is presented. Research question Across a population of patients and healthy subjects, do values for total...
Preprint
Full-text available
We show that the interaction of precipitating systems with local features can constrain the statistical description of extreme precipitation. These observational constraints can be used to project local extremes of low yearly exceedance probability (e.g., 100-year events) using synoptic-scale information from climate models without requiring climat...
Article
Full-text available
The tropical zonal-mean precipitation distribution varies between having single or double peaks, which are associated with intertropical convergence zones (ITCZs). Here, the effect of this meridional modality on the sensitivity of the ITCZ to hemispherically-asymmetric heating is studied using an idealized GCM with parameterized Ekman ocean energy...
Article
Full-text available
The role of tropical wind‐driven ocean circulation in setting the position of the Intertropical Convergence Zone (ITCZ) is studied using an atmospheric model coupled to a slab ocean with parameterized Ekman energy transport. Unlike previous studies, the parameterized cross‐equatorial ocean energy transport, which is critical for the coupled respons...
Article
Over the past 15 years, numerous studies have suggested that the sinking branches of Earth’s Hadley circulation and the associated subtropical dry zones have shifted poleward over the late 20 th century and early 21 st century. Early estimates of this tropical widening from satellite observations and reanalyses varied from 0.25° to 3° latitude per...
Article
While CMIP5 models robustly project drying of the subtropics and more precipitation in the tropics and subpolar latitudes by the end of the century, the magnitude of these changes in precipitation varies widely across models: for example, some models simulate no drying in the Eastern Mediterranean while others simulate more than a 50% reduction in...
Article
The Sahara was significantly greener 11-5 kya and during multiple earlier interglacial periods. But the mechanisms related to the greening of the Sahara remain uncertain as most climate models severely underestimate past wet conditions over north Africa. The variations in the African monsoon related to the greening of the Sahara are thought to be a...
Conference Paper
Full-text available
Heavy precipitation events (HPE) are a significant hydrometeorological phenomenon in the highly variable climate of the eastern Mediterranean (EM). They can cause flash-floods, and are closely-related to water availability. The formation of a HPE requires specific atmospheric conditions that result in relatively high precipitation efficiency, and c...
Article
Full-text available
Observational and modeling studies suggest that Earth's tropical belt has widened over the late 20th century and will continue to widen throughout the 21st century. Yet, estimates of tropical-width variations differ significantly across studies. This uncertainty, to an unknown degree, is partly due to the large variety of methods used in studies of...
Article
Full-text available
Megalakes in the Sahara? A Review – ADDENDUM - Volume 90 Issue 2 - Jay Quade, Elad Dente, Moshe Armon, Yoav Ben Dor, Efrat Morin, Ori Adam, Yehouda Enzel
Preprint
Full-text available
Background: Among the most basic measures of respiratory function is the total lung capacity (TLC). TLC is the pulmonary gas volume at maximal lung inflation, which is the sum of the volume of gas that can be exhaled (the vital capacity, VC) and the volume of gas that cannot (the residual volume, RV). Determination of VC requires only spirometry wh...
Article
The hydro-climatic conditions that prevailed during the last Glacial and early to mid-Holocene periods in South China are inferred from chemical compositions and Sr–Nd isotope ratios of sediments from lake Huguangyan Maar and its vicinity. The lake sediments are comprised of organic matter, volcanic materials and aeolian input from nearby granitoid...
Article
Full-text available
Current climate models represent the zonal- and annual-mean intertropical convergence zone (ITCZ) position in a biased way, with an unrealistic double precipitation peak straddling the equator in the ensemble mean over the models. This bias is seasonally and regionally localized. It results primarily from two regions: the eastern Pacific and Atlant...
Article
Full-text available
Observational and modeling studies suggest that Earth's tropical belt has widened over the late 20th century and will continue to widen throughout the 21st century. Yet estimates of tropical width variations differ significantly across studies. This uncertainty, to an unknown degree, is partly due to the large variety of methods used in studies of...
Article
There is mounting evidence that the width of the tropics has increased over the last few decades, but there are large differences in reported expansion rates. This is, likely, in part due to the wide variety of metrics that have been used to define the tropical width. Here we perform a systematic investigation into the relationship among nine metri...
Article
The Sahara was wetter and greener during multiple interglacial periods of the Quaternary, when some have suggested it featured very large (mega) lakes, ranging in surface area from 30,000 to 350,000 km ² . In this paper, we review the physical and biological evidence for these large lakes, especially during the African Humid Period (AHP) 11–5 ka. M...
Article
In recent decades, the subtropical edges of Earth's Hadley circulation have shifted poleward. Some studies have concluded that this observed tropical expansion is occurring more rapidly than predicted by global climate models. However, recent modeling studies have shown that internal variability can account for a large fraction of the observed circ...
Article
Full-text available
In the present climate, tropical rain bands exhibit a bifurcated pattern, continuously forming along single intertropical convergence zones (ITCZs) in some regions, and along double ITCZs that straddle the equator in other regions. This bifurcated ITCZ pattern is studied in a Matsuno-Gill-type model forced by relaxation to zonally asymmetric surfac...
Article
Full-text available
The Hadley circulation (HC) extent and strength are analyzed in a wide range of simulated climates from the last glacial maximum to global-warming scenarios. Motivated by HC theories, we analyze how the HC is influenced by the subtropical stability, the near-surface meridional potential temperature gradient, and the tropical tropopause level. The s...
Article
The ITCZ lies at the ascending branch of the tropical meridional overturning circulation, where near-surface meridional mass fluxes vanish. Near the ITCZ, column-integrated energy fluxes vanish, forming an atmospheric energy flux equator (EFE). This paper extends existing approximations relating the ITCZ position and EFE to the atmospheric energy b...
Article
We examine how tropical zonal mean precipitation biases in current climate models relate to the atmospheric energy budget. Both hemispherically symmetric and antisymmetric tropical precipitation biases contribute to the well-known double-Intertropical Convergence Zone (ITCZ) bias; however, they have distinct signatures in the energy budget. Hemisph...
Article
Full-text available
In the zonal mean, the ITCZ lies at the foot of the ascending branch of the tropical mean meridional circulation, close to where the near-surface meridional mass flux vanishes. The ITCZ also lies near the energy flux equator (EFE), where the column-integrated meridional energy flux vanishes. This latter observation makes it possible to relate the I...
Article
Full-text available
The Hadley circulation (HC) has widened in recent decades, and it widens as the climate warms in simulations. But the mechanisms responsible for the widening remain unclear, and the widening in simulations is generally smaller than observed. To identify mechanisms responsible for the HC widening and for model observation discrepancies, this study...
Article
The North Atlantic jet stream during winter 2010 was unusually zonal, so the typically separated Atlantic and African jets were merged into one zonal jet. Moreover, the latitude-height structure and temporal variability of the North Atlantic jet during this winter were more characteristic of the North Pacific. This work examines the possibility of...
Patent
Full-text available
A method for determining a pulmonary volume change includes: receiving a respiration event from a subject in an airflow chamber; interrupting the respiration event by an occlusion of the airflow chamber initiated at a first time instant and terminated at a second time instant subsequent to the first time instant; taking a plurality of measurements...
Article
Full-text available
The interaction of midlatitude eddies and the thermally driven Hadley circulation is studied using an idealized shallow-water model on the rotating sphere. The contributions of the annually averaged differential heating, vertical advection of momentum from a stationary boundary layer, and the gross effect of eddies, parameterized by Rayleigh dampin...
Article
Full-text available
A comparison is made between inviscid and viscous solutions of an axially symmetric nonlinear Shallow Water Model (SWM) of the Hadley circulation on the spherical rotating Earth that includes vertical advection of momentum and Rayleigh friction. The results of the 1D SWM are compared with those of 2D (latitude-height) nonlinear axially symmetric mo...
Article
Full-text available
An axially symmetric inviscid shallow-water model (SWM) on the rotating Earth forced by off-equatorial steady differential heating is employed to characterize the main features of the upper branch of an ideal Hadley circulation. The steady-state solutions are derived and analyzed and their relevance to asymptotic temporal evolution of the circulati...
Article
Full-text available
Solutions of an axially symmetric inviscid shallow-water model (SWM) on the earth forced by equinoctial differential heating are constructed using numerical integration of the time-dependent equations and analysis of their steady states. The study also maps the physical initial conditions and parameter values for which the solutions approach steady...
Article
The main features of upper tropospheric jetstreams are captured by an axial symmetric, Shallow Water Model (SWM), on the rotating spherical Earth in which the solar differential heating is parameterized. The differential is parameterized by relaxing the height of the troposphere to a prescribed latitude dependent height. Standard numerical integrat...

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Projects (2)