Ray Nassar

Image Ray Nassar
Research Scientist - Greenhouse Gas Measurements and Modelling

Current research and/or projects

  • Quantification of CO2 and CH4 sources and sinks using satellite-based and surface-based atmospheric CO2/CH4 observations and models
  • Retrieval and application of CO2 and CH4 concentrations from satellite observations
  • Studies 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/OCO-3, since 2007), Greenhouse Gases Observing Satellite (GOSAT/GOSAT-2, since 2009)
  • Reviewer for the Intergovernmental Panel on Climate Change (IPCC) Assessment Reports
  • Member of the Atmospheric Science Advisory Committee (ASAC) for the Canadian Space Agency (CSA) since 2017

Education and awards

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

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

Ph.D. University of Waterloo, 2006

B.Ed. Queen's University, 1998

B.Sc. University of Waterloo, 1998

Key publications

Nassar, R., J.-P. Mastrogiacomo, W. Bateman-Hemphill, C. McCracken, C.G. MacDonald, T. Hill, C. O'Dell, M. Kiel, D. Crisp, 2021. Advances in quantifying power plant CO2 emissions with OCO-2, Remote Sensing of Environment, 264, 112579, doi.org/10.1016/j.rse.2021.112579.

Nassar, R., C. McLinden, C.E. Sioris, C.T. McElroy, J. Mendonca, J. Tamminen, C.G. MacDonald, C. Adams, C. Boisvenue, A. Bourassa, R. Cooney, D. Degenstein, G. Drolet, L. Garand, R. Girard, M. Johnson, D.B.A. Jones, F. Kolonjari, B. Kuwahara, R.V. Martin, C.E. Miller, N. O'Neill, A. Riihela, S. Roche, S. Sander, W.R. Simpson, G. Singh, K. Strong, A.P. Trishchenko, H. van Mierlo, Z. Vaziri Zanjani, K.A. Walker, D. Wunch, 2019. The Atmospheric Imaging Mission for Northern Regions: AIM-North. Canadian Journal of Remote Sensing, 45, https://doi.org/10.1080/07038992.2019.1643707.

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.