Dr. Ray Nassar

Research Scientist - Greenhouse Gas Measurements and Modelling

4905 Dufferin Street (Toronto, ON)

CURRENT S&T / RESEARCH - Improving our understanding of natural and anthropogenic greenhouse gas (GHG) sources and sinks using surface and satellite observations and models

• Development of 3-D global atmospheric CO₂ models for investigating the natural carbon cycle and impacts of anthropogenic CO₂ emissions
• Retrieval and application of CO₂ concentrations from satellite observations
• Quantification of CO₂ sources and sinks by data assimilation using surface-based and satellite-based atmospheric CO₂ observations
• Observing System Simulation Experiments (OSSEs) to determine the benefit of planned or hypothetical satellite and surface CO₂ data sets

PROFESSIONAL ACTIVITIES / INTERESTS

• Science team member for the Atmospheric Chemistry Experiment (ACE, since 2000), Tropospheric Emission Spectrometer (TES, since 2006), Orbiting Carbon Observatory (OCO/OCO-2, participant/member since 2007), Greenhouse Gases Observing Satellite (GOSAT, since 2009), the Weather, Climate and Air quality (WCA) concept proposed for the Polar Communications and Weather (PCW) mission (since 2010)
• Reviewer for the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report
• Committee on Earth Observation Satellites (CEOS) Carbon Task Force member since 2011
• GEOS-Chem steering committee member and co-chair of the Carbon Gases and Organics working group, 2011-2015

KEY PUBLICATIONS

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.

Wang, H., D.J. Jacob, M. Kopacz, D.B.A. Jones, P. Suntharalingam, J.A. Fisher, R. Nassar, S. Pawson and J.E. Nielsen. 2009. Error correlation between CO₂ and CO as constraint for CO₂ flux inversions using satellite data. Atmospheric Chemistry and Physics, 9:7313-7323.

Nassar, R., J.A. Logan, I.A. Megretskaia, L.T. Murray, L. Zhang and D.B.A. Jones. 2009. Analysis of tropical tropospheric ozone, carbon monoxide and water vapor during the 2006 El Niño using TES observations and the GEOS-Chem model. Journal of Geophysical Research, 114:D17304, doi:10.1029/2009JD011760.

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.

Nassar, R., P.F. Bernath, C.D. Boone, G.L. Manney, S.D. McLeod, C.P. Rinsland, R. Skelton and K.A. Walker. 2005. Stratospheric abundances of water and methane based on ACE-FTS measurements. Geophysical Research Letters, 32:L15S04, doi:10.1029/2005GL022383.