Ray Nassar

Image Ray Nassar
Research Scientist - Greenhouse Gas Measurements and Modelling
Environment and Climate Change Canada

Current research and/or projects

Improving our understanding of greenhouse gas (GHG) sources and sinks using observations and models

  • Development of atmospheric CO2 models for investigating the natural carbon cycle and anthropogenic CO2 emissions
  • Retrieval and application of CO2 concentrations from satellite observations
  • Quantification of CO2 sources and sinks using satellite-based and surface-based atmospheric CO2 observations
  • Observing System Simulation Experiments (OSSEs) to determine the benefit of planned or hypothetical observing systems, such as future satellite missions

Professional activities / interests

  • Principal Investigator (PI) for AIM-North (The Atmospheric Imaging Mission for Northern regions) since 2017
  • Science team member for the Atmospheric Chemistry Experiment (ACE, since 2000), Orbiting Carbon Observatory (OCO/OCO-2, participant/member since 2007), Greenhouse Gases Observing Satellite (GOSAT, since 2009)
  • Reviewer for the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report
  • Committee on Earth Observation Satellites (CEOS) Carbon Task Force report writing team member since 2011
  • GEOS-Chem steering committee member and co-chair of the Carbon Gases and Organics working group, 2011-2015

Education and awards

Ph.D. University of Waterloo, 2006

B.Ed. Queen's University, 1998

B.Sc. University of Waterloo, 1998

Key publications

Nassar, R., T.G. Hill, C.A. McLinden, D. Wunch, D.B.A. Jones, D. Crisp. 2017. Quantifying CO2 emissions from individual power plants from space. Geophysical Research Letters, 44. https://doi.org/10.1002/2017GL074702.

Nassar, R., C.E. Sioris, D.B.A. Jones, J.C. McConnell. 2014. Satellite observations of CO2 from a highly elliptical orbit for studies of the Arctic and boreal carbon cycle. Journal of Geophysical Research: Atmospheres, 119, 2654-2673.

Garand, L., A.P. Trishchenko, L. Trichtchenko, R. Nassar. 2014. The Polar Communications and Weather Mission: Addressing remaining gaps in the Earth Observing System, Physics in Canada, 70 (4), 247-254.

Deng, F., D.B.A. Jones, D.K. Henze, N. Bousserez, K.W. Bowman, J.B. Fisher, R. Nassar, C. O'Dell, D. Wunch, P.O. Wennberg, E.A. Kort, S.C. Wofsy, T. Blumenstock, N.M. Deutscher, D. Griffith, F. Hase, P. Heikkinen, V. Sherlock, K. Strong, R. Sussmann, T. Warneke. 2014. Inferring regional sources and sinks of atmospheric CO2 from GOSAT XCO2 data. Atmospheric Chemistry and Physics, 14, 3703-3727.

Nassar, R., L. Napier-Linton, K.R. Gurney, R.J. Andres, T. Oda, F.R. Vogel, F. Deng. 2013. Improving the temporal and spatial distribution of CO2 emissions from global fossil fuel emission datasets. Journal of Geophysical Research: Atmospheres, 118, 917-933.

Nassar, R., D.B.A. Jones, S.S. Kulawik, J.R. Worden, K.W. Bowman, R.J. Andres, P. Suntharalingam, J.M. Chen, C.A.M. Brenninkmeijer, T.J. Schuck, T.J. Conway, D.E. Worthy. 2011. Inverse modeling of CO2 sources and sinks using satellite observations of CO2 from TES and surface flask measurements. Atmospheric Chemistry and Physics, 11:6029-6047.

Nassar, R., D.B.A. Jones, P. Suntharalingam, J.M. Chen, R.J. Andres, K.J. Wecht, R.M. Yantosca, S.S. Kulawik, K.W. Bowman, J.R. Worden, T. Machida and H. Matsueda. 2010. Modeling global atmospheric CO2 with improved emission inventories and CO2 production from the oxidation of other carbon species. Geoscientific Model Development, 3:689-716.

Kulawik, S.S., D.B.A. Jones, R. Nassar, F.W. Irion, J.R. Worden, K.W. Bowman, T. Machida, H. Matsueda, Y. Sawa, S.C. Biraud, M. Fisher and A.R. Jacobson. 2010. Characterization of Tropospheric Emission Spectrometer (TES) CO2 for carbon cycle science. Atmospheric Chemistry and Physics, 10:5601-5623.

Payne, V.H., S.A. Clough, M.W. Shephard, R. Nassar and J.A. Logan. 2009. Information-centered representation of retrievals with limited degrees of freedom for signal: Application to methane from the Tropospheric Emission Spectrometer. Journal of Geophysical Research, 114:D10307, doi:10.1029/2008JD010155.

Affiliations

University of Toronto, Department of Physics, NSERC Postdoctoral Fellow, 2008-2010

Harvard University, Atmospheric Chemistry Modelling Group, Postdoctoral Fellow, 2006-2008