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Raymond G. Najjar, Jr.
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Raymond G. Najjar, Jr.

  • Professor of Oceanography
  • Joint Appointment with the Department of Geosciences
522 Walker Building
University Park, PA 16802
Phone: (814) 863-1586


  1. B.E., Mechanical Engineering, The Cooper Union for the Advancement of Art & Science
  2. M.A., Geophysical Fluid Dynamics, Princeton University
  3. Ph.D., Atmosphere and Ocean Science, Princeton University

Research Specialties:


Most of my work that directly involves climate is about the impact of climate change on coastal regions, especially estuaries of the Mid-Atlantic Region of the U.S.  This study is a literature review that focuses on climate change impacts on the Chesapeake Bay.  I am particularly interested in how climate change, through changing streamflow patterns, and sea-level rise, alters the salinity of estuaries.  I've also become interested in evaluating the skill of global climate models at regional scales, which is highlighted in two studies:  one is about watersheds of the Mid-Atlantic and the other is part of an assessment of climate change impacts on Pennsylvania.

Most of my oceanographic research has been in the field of marine biogeochemistry, with a particular focus on dissolved gases, like carbon dioxide, oxygen, carbon monoxide, carbonyl sulfide and dimethyl sulfide.  A current activity in this area is my involvement in the USECoS project, which, through modeling, data analysis, and field observations, is focused on the carbon cycle of the continental shelf of the Eastern U.S.


  • Co-Chair Science Steering Group of North American Carbon Program
  • Member Science and Technical Advisory Committee of the Chesapeake Bay Program

Selected courses taught

Selected publications

(Click here for full list)

Signorini, S., Mannino, A., Friedrichs, M.A.M., Najjar, R.G., Cai, W.-J., Salisbury, J.E., Wang, Z.A., Thomas, H., Shadwick, E., 2013. Surface ocean pCO2 seasonality and sea-air CO2 flux estimates for the North American east coast. Journal of Geophysical Research, 118, 5439–5460.

Ning, L., Mann, M.E., Crane, R., Wagener, T., Najjar, R.G., Singh, R., 2012. Probabilistic projections of anthropogenic climate change impacts on precipitation for the Mid-Atlantic Region of the United States. Journal of Climate, 25, 5273-5291.

Nese, J.M., Najjar, R.G., Murgo, J., 2012. Climate science and the broadcast meteorologist. Bulletin of the American Meteorological Society, 93, 1913-1916.

Kim, T.W., Najjar, R.G., Lee, K., 2012. Influence of precipitation events on phytoplankton biomass in coastal waters of the eastern United States. Global Biogeochemical Cycles, 28, doi:10.1002/2013GB004712, 1-13.

Kim, T.-W., Lee, K., Najjar, R.G., Jeong, H.-D., Jeong, H.J., 2011. Increasing N abundance in the Northwestern Pacific Ocean due to atmospheric nitrogen deposition. Science, 334, 505-509.

Katz, B., Najjar, R., Cronin, T., Rayburn, J., Mann, M.E., 2011. Constraints on Lake Agassiz discharge through the late-glacial Champlain Sea (St. Lawrence Lowlands, Canada) using salinity proxies and an estuarine circulation model. Quaternary Science Reviews, 30, 3248-3257.

Najjar, R. G., C. R. Pyke, M. B. Adams, D. Breitburg, M. Kemp, C. Hershner, R. Howarth, M. Mulholland, M. Paolisso, D. Secor, K. Sellner, D. Wardrop, and R. Wood. 2010.  Potential climate-change impacts on the Chesapeake Bay. Estuarine, Coastal, and Shelf Science, 86, 1-20.

Najjar, R. G., L. Patterson and S. Graham. 2009. Climate simulations of major estuarine watersheds in the Mid-Atlantic region of the United States. Climatic Change, 95, 139-168.

Wu, S.-Y., R. G. Najjar, and J. Siewert. 2009. Potential impacts of sea-level rise on the Mid- and Upper-Atlantic Region of the United States. Climatic Change, 95,121-138.

Fennel, K., J. Wilkin, M. Previdi, and R. Najjar. 2008. Denitrification effects on air-sea CO2 flux in the coastal ocean: Simulations for the northwest North Atlantic. Geophysical Research Letters, 35, L24608, doi: 10.1029/2008GL036147.

Hilton, T. H., R. G. Najjar, L. Zhong, and M Li. 2008. Is there a signal of sea-level rise in Chesapeake Bay salinity? Journal of Geophysical Research., 113, C09002, doi: 10.1029/2007JC00427.

Bailey, K. E., D. A. Toole, B. Blomquist, R. G. Najjar, B. Huebert, D. J. Kieber, R. P. Kiene, P. Matrai, G. R. Westby, and D. A. del Valle. 2008. Dimethylsulfide production in Sargasso Sea eddies. Deep-Sea Research II, 55, 1491-1504.

Hoffman, E., J.-N. Druon, K. Fennel, M. Friedrichs, D. Haidvogel, C. Lee, A. Mannino, C. McClain, R. Najjar, J. O'Reilly, D. Pollard, M. Previdi, S. Seitzinger, J. Siewert, S. Signorini, and J. Wilkin. 2008. Eastern US continental shelf carbon budget: Integrating models, data assimilation, and analysis. Oceanography, 21(1), 86-104.

Zafiriou, O. C., H. Xie, N. B. Nelson, and R. G. Najjar. 2008. Carbon monoxide distributions reveal upper-ocean diel- and seasonal-scale photochemistry, biogeochemistry and mixing. Limnology and Oceanography, 53, 835-850.

Najjar, R. G., and 22 others. 2007. Impact of circulation on export production, dissolved organic matter and dissolved oxygen in the ocean: Results from Phase II of the Ocean Carbon-cycle Model Intercomparison Project (OCMIP-2), Global Biogeochemical Cycles, 21, GB3007, doi:10.1029/2006GB00285.

Berelson, W. M., W. M. Balch, R. Najjar, R. A. Feely, C. Sabine, K. Lee. 2007. Relating estimates of CaCO3 production, export, and dissolution in the water column to measurements of CaCO3 rain into sediment traps and dissolution on the sea floor: A revised global carbonate budget. Global Biogeochem. Cycles, 21, GB1024, doi: 10.1029/2006GB002803.

Jin, X., R. G. Najjar, F. Louanchi, and S. C. Doney. 2007. A modeling study of the seasonal oxygen budget of the global ocean. Journal of Geophysical Research, 112, C05017, doi:10.1029/2006JC003731.