Dr Eran Tas

Holds the Joseph H. and Belle R. Braun senior lectureship in Agriculture

Higher Education

2010-2012, Post-doctoral fellowship in cloud microphysics, Weizmann Institute of Science.

2007-2009, Post-doctoral fellowship in multiphase atmospheric chemistry modelling and model development, Max Planck Institute for Chemistry.

2001-2007, Ph.D in Atmospheric Chemistry / measurements & modeling, The Hebrew University

1998-2000, M.Sc in air-pollution and trans-boundary transport, The Hebrew University.

1994-1997, B.Sc. in chemistry, The Hebrew University.

Research Interests

Soil-plant-atmosphere continuum

Atmospheric chemistry

Air pollution

Cloud microphysics

rootMemnber of the the Root of the Matter Monitoring Project

 

Eran_Tas_CV.pdf72 KB
See also: Eran_Tas

Research

Soil-plant-atmosphere continuum

Since the pre-industrial period enhanced anthropogenic activity imbalanced the chemical equilibrium between soil, water and plants, via many feedbacks, which are still under study. An extremely sharp rise in the levels of air-pollutants alters the biogeochemical cycles and damages plants and agriculture in many ways, relevant from the local to global scale. On the other hand, vegetation also affects the climate and the composition of the atmosphere in many different ways. Our group focuses on gas exchange between natural and agricultural vegetation and the atmosphere under Mediterranean and semi-arid climate conditions. The interrelationship between vegetation, air-pollution and key processes in the atmosphere are of special interest.

The main focus is on:

 i) biogenic volatile organic compounds (BVOCs) emission from vegetation and its impact on local scale ozone destruction and regional ozone formation under Mediterranean and semi-arid conditions

 ii) Ozone (O3) uptake by plants and associated effects on both plants functioning and increase in atmospheric carbon dioxide

 iii) Impact of methyl halides emissions from natural sources (soil, seawater and plants) on stratospheric and tropospheric ozone destruction.

 iv) Evapotranspiration and its forecasting.

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To answer these questions we use highly precise and fast sensors to quantify the concentrations of e.g., BVOCs, O3, CO2 and H2O and quantify their flux by using the eddy covariance technique and complementary measurements. Other tools we use include detailed atmospheric chemistry models (e.g., CAABA-MECCA) and regional models (e.g., WRF and WRF-Chem) in order to study the implications of the emitted gases on key processes in the atmosphere. Read more…

measurements 
Eddy covariance & meteorological measurements

measurements 
Complementary measurements

 

 

 

See also: Eran_Tas

Projects

Projects: Soil-plant-atmosphere continuum

The role of biogenic volatile organic compounds in regional ozone formation under global warming: investigation in the Mediterranean Basin

The Hebrew University/ The Jerusalem college of Technology (funded by the Israel Science Foundation), Berkeley University.
Qian Li, Maor Gabay, Chen Cohen, Tali Rodkov
Starting year - 2015

Biogenic volatile organic compounds (BVOCs) emitted from vegetation account for approximately 90% of total global VOC emissions. BVOCs play important roles in key processes, which affect air pollution, the radiation budget and climate. Mediterranean regions are occasionally characterized by strong photochemical activity and high ozone (O3) concentrations. Emission of BVOCs in Mediterranean forests are at relatively high rates, induced by high temperatures and sunny conditions and have been of special interest in the past few decades because they have been identified as an important factor in regional air pollution control strategies and climate related properties. Global warming acts to increase temperature and dryness in Mediterranean regions, which in turn leads to an increase in O3 concentrations. Drought conditions, high temperature and high O3 levels, are also recognized as stress factors which enhance and change BVOC emission rates and patterns.

However, currently there is lack of data from field measurements to understand the impact of multiple, co-occurring stress factors on BVOC emission. Moreover, our current ability to model and assess the impact of BVOC emissions on O3 formation is limited. Two major uncertainty sources include insufficient knowledge about the BVOC emission rate and speciation and inaccuracies in photochemical mechanisms. Our study is aimed at quantifying the impact of BVOCs emitted from two typical Mediterranean forests on regional O3 formation, by interaction with anthropogenic air pollution emitted upwind of the forests, to quantify BVOC, O3, CO2 and H2O net exchange flux over the forests, using the Eddy Covariance (EC) method. BVOC flux is quantified by using a proton transfer reaction–time of flight–mass spectrometer (PTR-TOF-MS).

Branch-level measurements will be performed in order to quantify BVOC emissions from specific vegetation, followed by GC-MS analyses. Recent studies indicate that using the PTR-ToF-MS, enables quantifying extremely large numbers of BVOC compounds compared with past measurements, which can significantly improve our understanding of the contribution of BVOCs to photochemical pollution formation and climate-related properties.

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We will use the WRF-Chem model in order to simulate the contribution of the measured BVOC fluxes to regional O3 formation. Chemical pathways for new identified species may be added, subjected to sensitivity analysis by a chemical-lagrangian box model. Emission fluxes in the model will be based on a detailed emission inventory available for the studied region.

The O3 concentrations obtained by WRF-Chem will be evaluated using available data on trace gas concentration in the region, from a continuous measurement network operated by the Israel Ministry of Environmental Protection.

We believe that this study will enable improving our understanding of BVOC emissions in Mediterranean regions and elsewhere. In particular, the Mediterranean Basin, is recognized as a climate change “hot spot”, where high O3concentrations, high temperature, and drought conditions tend to occur simultaneously during the warm seasons. Therefore, this region can be used as a natural laboratory to study BVOC emissions and its influence on regional O3 formation, under the influence of global warming-related properties.

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Measurement-Based Modeling of Methyl halides emission in the Dead Sea

The Hebrew University – Berkeley university – UC Irvine / funded by the  United States – Israel Science Foundation
Moshe Shechner
Starting year - 2013

 The contribution of terrestrial ecosystems to the atmospheric concentrations of methyl halides is poorly quantified, although they play a key role in several important processes in the atmosphere, including tropospheric and stratospheric ozone destruction. We use advanced methods to separately sample air in the downward and upward flux, which is followed by analysis of the sampled air for CH3Cl, CH3Br and CH3I, as well as C2H2Cl2 using GC-MS. Measurements take place at the Dead Sea, representing a salt lake environment under semi-arid conditions, during different seasons, in several different sites over seawater, bare soil and vegetation, which enable investigation of the emission and deposition strength of these components. The analyzed iodine species are used as input for atmospheric chemical simulations, using the MECCA model, in an attempt to identify the source of IO formation in this area, and in order to characterize the potential impact on tropospheric ozone destruction.

Investigating the impact of alternative fuels for transportation using a detailed chemical atmospheric model

The Hebrew University
Maor Gabay
Starting year – 2015

In this research we aim at investigating the impact of using alternative fuels for transportation by applying a highly detailed atmospheric chemistry model.

Improving Israeli wheat productivity under exposure to ozone

The Hebrew University – ARO (Volcani Center) Bar Ilan University
Starting year - 2016

The global economic damage associated with O3 uptake by crops is currently estimated to be about $11-26 billion annually (e.g., see http://icpvegetation.ceh.ac.uk/publications/documents/ozoneandfoodsecurity-ICPVegetationreport%202011-published.pdf), and is expected to significantly increase by 2030 (e.g., $17 - $35 billion annually for the IPCC A2 scenario). While bread wheat (Triticum aestivum) is considered to be one of the most ozone-sensitive crops identified to date, no specific information is available for wheat loss due to exposure to ozone in Israel. This project is a multidisciplinary research aimed at improving Israeli wheat productivity and quality under the unique conditions prevalent in Israel. The aim of our group is to shed light on the impact of atmospheric ozone and wheat, by selection of the most ozone-resistant cultivars under the specific growing conditions of a specific growing area. Experiments using open top chambers (OTCs) are going to be used for this research.

Read more: http://israel-wheat.wix.com/mizam 

Ozone uptake by vegetation under semi-arid and Mediterranean conditions

The Hebrew University – The Weizmann Institute - The Jerusalem college of Technology
Qian Li, Maor Gabay, Yoav Rubin, Shani Rohatyn, Tali Rodkov
Starting year -2013

Our group investigates, also in collaboration with the research group of Professor Dan Yakir (Weizmann Institute) the ozone uptake by forests, as well as agricultural fields, in several measurement sites along the Israeli climatic gradient, while trying to identify ozone deposition rate, and the related impact on net ecosystem exchange (NEE), transpiration and evaporation under semiarid conditions (e.g., Yatir forest) and typical Mediterranean forests.

Irrigation scheduling for row crops using potential evapotranspiration and rain forecasting

The Hebrew University – Ben Gurion University (funded by the Israel agriculture ministry), The Jerusalem College of Technology
Theodor Bughici
Starting year – 2015

This research is aimed at improving high -resolution irrigation scheduling efficiency, by using the WRF-Chem atmospheric model combined with the HYDRUS model. By comparing WRF predictions and measured meteorological parameters in meteorological stations, we aim at improving the evaporation predictions over Israel. Since 2015, The two universities are working in collaboration with the group of Professor Erick Fredj from (The Jerusalem College of Technology), in the setup/run/analysis of the WRF-Chem model.

See also: Eran_Tas

Publications

List of publications / Eran Tas

Gabay, M., and Tas, E. (2019). Dispersion-box modeling investigation of the influences of gasoline,diesel, M85 and E85 vehicle exhaust emission on photochemistry, Environ. Pollut, 252, 1863-1871, https://doi.org/10.1016/j.envpol.2019.05.142.

Shechner, M., Guenther, A., Rhew, R., Wishkerman, A., Li, Q., Lerner, G., and Tas, E. (2019). Emission of volatile halogenated organic compounds over various landforms at the Dead Sea, Atmos. Chem. Phys., 19, 7667-7690, doi: 10.5194/acp-19-7667-2019.

Bughici, T., Lazarovitch, N., Fredj, E., and Tas, E. (2019). Evaluation and Bias Correction in WRF Model Forecasting of Precipitation and Potential Evapotranspiration, J. Hydrometeorol., 20, 965-983, https://doi.org/10.1175/JHM-D-18-0160.1

Li, Q., Gabay, M., Rubin, Y., Raveh-Rubin, S., Rohatyn, S., Tatarinov, F., Rotentberg, E., Ramati, E., Dicken, U., Preisler, Y., Fredj, E., Yakir, D. and Tas, E. (2019).  Investigation of ozone deposition to vegetation under warm and dry conditions near the Eastern Mediterranean coast, Sci. Total Environ., 658, 1316-1333, https://doi.org/10.1016/j.scitotenv.2018.12.272

Li, Q., Gabay, M., Rubin, Y., Fredj, E., and Tas, E. (2018). Measurement-based investigation of ozone deposition to vegetation under the effects of coastal and photochemical air pollution in the Eastern Mediterranean, Sci. Total Environ., 645, 1579–1597, doi.org/10.1016/j.scitotenv.2018.07.037.

Rohatyn, S., Rotenberg, E., Ramati, E., Tatarinov, F., Tas, E. and Yakir, D. (2018).  Differential impacts of land use and precipitation on 'ecosystem water yield’, Water. Resour. Res., doi: doi: 10.1029/2017WR022267.

Shechner, M., and Tas, E. (2017). Ozone formation induced by the impact of reactive bromine and iodine species on photochemistry in a polluted marine environment, Environ. Sci. Technol., 51, 24, 14030-14037. https://doi.org/10.1021/acs.est.7b02860

Bluvshtein, N., Lin, P., Flores, J. M., Segev, L., Mazar, Y., Tas, E., Snider, G., Weagle, C., Brown, S. S., Laskin, A. and Rudich, Y (2017). Broadband optical properties of biomass-burning aerosol and identification of brown carbon chromophores, J. Geophys. Res. Atmos., 122(10), 5441–5456, doi: 10.1002/2016JD026230

M. Peleg, E. Tas, V. Matveev, D. Obrist, C. Moore, M. Gabay and M. Luria (2015). Contribution of the Nitrate Radical to Oxidation of Gaseous Elemental Mercury, Environ. Sci. Technol., 49,24, 14008–14018. doi: 10.1021/acs.est.5b03894

Tas, E., Teller, A., Altaratz, O., Axisa, D., Bruintjes, R., Levin, Z., Koren, I., (2015). The relative dispersion of cloud droplets: its robustness with respect to key cloud properties, Atmos. Chem. Phys., 12, 2429-2440, doi:10.5194/acp-12-2429-2015

Tas, E., Koren, I., and Altaratz, O (2012). On the sensitivity of droplet size relative dispersion to warm cumulus cloud evolution, Geophys. Res. Lett., 39, L13807,https://doi.org/10.1029/2012GL052157

Tas, E., Obrist, D., Peleg, M., Faïn X., Asaf, D., and Luria M (2012). Measurement-based modeling of bromine-induced oxidation of mercury above the Dead Sea, Atmos. Chem. Phys., 12, 2429-2440, doi:10.5194/acp-12-2429-2012.

Asaf, D., Peleg, M., Alsawair, J., Soleiman, A., Matveev, V. Tas, E., Gertler, A., and Luria, M (2011). Transboundary transport of ozone from the Eastern Mediterranean Coast, Atmos. Env.,45, 5595-5601. doi: 10.1016/j.atmosenv.2011.04.045

Obrist, D., Tas, E., Peleg, M., Matveev, V., Faïn, X., Asaf, D., Luria, M (2011). Bromine-induced oxidation of mercury in the mid-latitude atmosphere, Nature Geosci., 4, 22-26. doi: 10.1038/ngeo1018

Asaf, D., Tas, E., Pedersen, D., Peleg M., and Luria, M (2010). Long-term measurements of NO3 radical at a semi-arid urban site: 2. Seasonal trends and loss mechanisms, Environ. Sci. Technol, 44, 5901–5907. doi: 10.1021/es100967z

Tas, E., Peleg, M., Pedersen, D. U., Matveev, V., Pour Biazar, A., and Luria, M (2008). Measurement-based modeling of bromine chemistry in the Dead Sea boundary layer – Part 2: The influence of NO2 on bromine chemistry at mid-latitute areas, Atmos. Chem. Phys., 8, 4811-1821. doi: 10.5194/acp-8-4811-2008

Peleg, M., Matveev, V.,Tas, E., Luria, M. Valente, R. J., and Obrist D (2007). Mercury Depletion Events in the Troposphere in Mid-Latitudes at the Dead Sea, Israel, Environ. Sci. Technol., 41 (21), 7280-7285. https://doi.org/10.1021/es070320j

Tas, E., Peleg, M., Pedersen, D. U., Matveev, V, Pour Biazar, A., and Luria, M (2006). Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea, Atmos. Chem. Phys., 6, 5589-5604. doi: 10.5194/acp-6-5589-2006

Tas, E., Peleg, M., Matveev, V., Zingler, J., and Luria, M   (2005). Frequency and extent of bromine oxide formation over the Dead Sea, J. Geophys Res.,Vol.110,No.D11,D11304  https://doi.org/10.1029/2004JD005665

Tas, E., Matveev, V., Zingler, J., Luria, M., and Peleg, M (2003). Frequency and extent of ozone destruction episodes over the Dead Sea, Israel, Atmos. Environ., 37 (34), 4769-4780.  https://doi.org/10.1016/j.atmosenv.2003.08.015

Matveev, V., Dayan, U ., Tas, E. , Peleg, M  (2002). Atmospheric sulfur flux rates to and from Israel, Sci. Total. Environ., 291, 143-154. doi: 10.1016/S0048-9697(01)01089-0

 

See also: Eran_Tas

Group Members

Eran Tas  head  eran.tas@mail.huji.ac.il

Maor Gabay  Ph.D student  maor.armon@mail.huji.ac.il

Yoav Rubin  M.Sc. student  yoav.rubin@mail.huji.ac.il

Moshe Shechner  M.Sc. student  moshe.shechner@mail.huji.ac.il

Shani Rohatyn  M.Sc. student  shani.roahtyn@weizmann.ac.il  (co-supervisor: Prof. Dan Yakir)

Tali Rodkov  M.Sc. student  tali.rodkov@mail.huji.ac.il

Amit Sabag  undergraduate student  amit.sabag@mail.huji.ac.il

Shmuel Rabinovitch  undergraduate student  1990sr@gmail.com

Gil Lerner  Projector & technician  gil.lerner@mail.huji.ac.il

 

 

See also: Eran_Tas

Open Positions

Our research group is seeking PhD candidates for a challenging project to study
photochemical air-pollution formation over Israel and the Eastern Mediterranean Sea.
A special focus is given to the effect of vegetation on air-pollution and climate change
components. The analysis is based on atmospheric chemistry and physics modelling
of measured data.

* Requirements - Bachelor in exact sciences/engineering & programming skills

* High scholarship

* Collaboration with Israeli research institutes

* Research is funded by the Israel science foundation and Israeli ministry of
environmental protection

For more details please contact Dr. Eran Tas
eran.tas@mail.huji.ac.il

 

 

See also: Eran_Tas