Raymond G. Najjar, Jr.

Raymond G. Najjar, Jr.

  • Professor of Oceanography
  • Joint Appointment with the Department of Geosciences
522 Walker Building
University Park, PA 16802
Email: rgn1@psu.edu
Phone: (814) 863-1586


  1. B.E., Mechanical Engineering, The Cooper Union for the Advancement of Art & Science, 1985
  2. Ph.D., Atmosphere and Ocean Science, Princeton University, 1990
  3. Post-Doctoral Scholar, National Center for Atmospheric Research, 1990–1993

Research Specialties:


My climate-related research focuses on the impact of climate change on coastal regions. For example, I am interested in how changes in streamflow and sea level influence salinity, circulation, and water quality of estuaries.


My work in oceanography is broad, and includes studies on the physics, chemistry, and biology of the sea. Carbon and oxygen are of particular interest to me because they reveal a lot about how the ocean operates and interacts with the atmosphere. My earlier research was dominated by open-ocean and global studies, which I still retain an interest in. Most of my current research is focused on coastal systems.


Courses taught

  • Marine Biogeochemistry (Geosc 410)
  • Introductory Meteorology (Meteo 003)
  • Fundamentals of Atmospheric Science (Meteo 300)
  • Atmospheric Dynamics (Meteo 421)
  • Introduction to Physical Oceanography (Meteo 451)
  • Geophysical Fluid Dynamics (Meteo 520)
  • Physical Oceanography (Meteo 551)
  • Communication of Research in Atmospheric Science (Meteo 880)

Selected publications

Click here for full publication list

Cavallaro, N., Shrestha, G., Birdsey, R., Mayes, M.A., Najjar, R.G., Reed, S.C., Romero-Lankao, P., Zhu, Z. (Editors), 2018. Second State of the Carbon Cycle Report (SOCCR2): A Sustained Assessment Report. U.S. Global Change Research Program, Washington, DC, USA, 878 pp.

Najjar, R.G., Herrmann, M., Alexander, R., Boyer, E.W., Burdige, D.J., Butman, D., Cai, W.-J., Canuel, E.A., Chen, R.F., Friedrichs, M.A.M., Feagin, R.A., Griffith, P.C., Hinson, A.L., Holmquist, J.R., Hu, X., Kemp, W.M., Kroeger, K.D., Mannino, A., McCallister, S.L., McGillis, W.R., Mulholland, M.R., Pilskaln, C.H., Salisbury, J., Signorini, S.R., St-Laurent, P., Tian, H., Tzortziou, M., Vlahos, P., Wang, Z.A., Zimmerman, R.C., 2018. Carbon budget of tidal wetlands, estuaries, and shelf waters of Eastern North America. Global Biogeochemical Cycles 32, 389–416.

Bannon, P.R., Najjar, R.G., 2018. Heat-engine and entropy-production analyses of the world ocean. Journal of Geophysical Research: Oceans 123, 8532–8547.

St-Laurent, P., Friedrichs, M.A.M., Najjar, R.G., Herrmann, M., Miller, S., Martins, D., Wilkin, J., 2017. Impacts of atmospheric nitrogen deposition on surface waters of the Western North Atlantic mitigated by multiple feedbacks. Journal of Geophysical Research: Oceans 122, 8406–8426.

Ross, A.C., Najjar, R.G., Li, M., Lee, S.B., Zhang, F., Liu, W., 2017. Fingerprints of sea-level rise on changing tides in the Chesapeake and Delaware Bays. Journal of Geophysical Research: Oceans 122, 8102–8125.

Walker, A., Titley, D.W., Mann, M.E., Najjar, R.G., Miller, S.K., 2018. A fiscally based scale for tropical cyclone storm surge. Weather and Forecasting 33, 1709–1723.

Seidensticker, L., Najjar, R.G., Herrmann, M., Boyer, J.N., Briceño, H.O., Kemp, W.M., Tomaso, D., 2018. Seasonal and interannual variability in net ecosystem production of a subtropical coastal lagoon inferred from monthly oxygen surveys. Estuaries and Coasts.

Schulte, J., Najjar, R.G., Li, M., 2016. The influence of climate modes on streamflow in the Mid-Atlantic Region of the United States. Journal of Hydrology: Regional Studies 5, 80–99.

Mannino, A., Signorini, S.R., Novak, M.G., Wilkin, J., Friedrichs, M.A.M., Najjar, R.G., 2016. Dissolved organic carbon fluxes in the Middle Atlantic Bight: An integrated approach based on satellite data and ocean model products. Journal of Geophysical Research: Biogeosciences 121, 312–336.

Tomaso, D., Najjar, R., 2015. Long-term variations in the dissolved oxygen budget of an urbanized tidal river: The Upper Delaware Estuary. Journal of Geophysical Research: Biogeosciences 120, 1027–1045.

Herrmann, M., Najjar, R.G., Kemp, W.M., McCallister, S.L., Alexander, R.B., Cai, W.-J., Griffith, P., Smith, R.A., 2015. Net ecosystem production and organic carbon balance of U.S. East Coast estuaries. Global Biogeochemical Cycles, 29, 96–111.

Schulte, J., Duffy, C., Najjar, R.G., 2015. Geometric and topological approaches to significance testing in wavelet analysis. Nonlinear Processes in Geophysics, 22, 139–156.

Ross, A.C., Najjar, R.G., Li, M., Mann, M.E., Ford, S.E., Katz, B., 2015. Sea-level rise and other influences on decadal-scale variations of salinity in a coastal plain estuary. Estuarine Coastal and Shelf Science, 157, 79–92.

Bannon, P.R., Najjar, R.G., 2014. Available energy of the world ocean. Journal of Marine Research, 72, 219–242.

Kim, T.W., Najjar, R.G., Lee, K., 2014. 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.

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.

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.

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.

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.

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.