My primary research goal is to understand the physical processes that determine the circulation in the coastal ocean. My students and I are currently involved in both the construction and testing of models and the development of observational techniques. I am also interested in fundamental geophysical and environmental fluid dynamics and the application of mathematical and statistical methods to the development of models of biogeochemical processes.

River Plumes

At the mouths of many rivers, thin layers of brackish fluid are found at the surface. Unfortunately, existing simulations of water quality in estuaries cannot resolve these features; and, since they are very shallow and transient, it is also difficult to make measurements of their structure. I have developed a model of the dynamics of these phenomena and have recently constructed a ship-mounted instrument array to observe their structure. It is currently being employed to study the plume formed by the Connecticut River in Long Island Sound.

Circulation in Long Island Sound

The long-term movement of water in Long Island Sound strongly influences the water quality. I am currently collaborating with several members of the Department of Marine Sciences faculty on observational programs to determine the structure and evolution of the flow field in the Sound.

Fundamental Geophysical and Environmental Fluid Dynamics

Much has been reamed about the dynamics of the ocean and atmosphere by the study of simple models that include only the dominant processes. Recently, I have contributed to the explanation of the subtle effects of nonlinear processes and stratification in the Rossby and spin-up problems in simple geometries. In collaboration with a student, I am currently developing models of tidally induced residual circulation in idealized coastal plain estuaries and intend to extend this work to more realistic geometries.

Mathematical Models of Environmental Processes

I have recently collaborated with Department of Marine Sciences faculty and students on the application of methods of applied mathematics to the development of models of bioturbation in marine sediments, the cycling of mercury in the equatorial Pacific and the diffusion of Radon from fractured rocks. I am currently working on several related models.

Dagg, M., R. Benner, S. Lohrenz, and J. O'Donnell (2002). Transport and transformation of dissolved and particulate materials on continental shelves influenced by large rivers: plume processes. Cont. Shelf. Res. (submitted).

Lambourg, C. H., W.F.Fitzgerald, J. O'Donnell and T. Torgersen (2002). A Non-steady state compartmental model of global-scale Mercury biogeochemistry with interhemispheric atmospheric gradients. Geochimica et Cosmochimica Acta Geochimica et Cosmochimica Acta, Vol. 66, No. 7, pp. 1105-1118, 2002

Wang, Y-H,. W.F. Bohlen and J. O'Donnell. 2000. Storm Enhanced Bottom Shear Stress and Associated Sediment Entrainment in a Moderate Energetic Estuary. Journal of Oceanography, Vol. 56, No. 3, pp. 311-317, 2000,

O'Donnell, J., G.O. Marmorino and C.L. Trump, 1998. Convergence and downwelling at a river plume front. J. Phys. Oceanogr. v28, 1481-1495

Li, C. and J. O'Donnell, 1998. On the residual flow in tidal rivers and shallow estuaries. Chin. J. Oceanology and Limnology. 6 (1). 1-8.

Bogden, P.S. and J.O'Donnell, 1997. Generalized Inverse analysis of current measurements from a moving ship: estimating the tidal and non-tidal flows in Long Island Sound. J. Marine Res. 56, 989-1014.

Li, C. and J. O'Donnell, 1997. Tidally driven residual circulation in estuaries with lateral depth variations. J. Geophys. Res. 102, 27913-27929.
O'Donnell, J. 1997. Observations of near surface currents and hydrography in the Connecticut River plume with the SCUD array. J. Geophys. Res. 102, 25021-25033.

Torgersen, T., E. DeAngelo, and J. O'Donnell, 1997. Calculation of horizontal mixing rates using 222Rn and the controls on hypoxia in western Long Island Sound, 1991. Estuaries, 20, 328-345.

O'Donnell, J., A. A. Allen and D. L. Murphy. 1997. An assessment of the errors in Lagrangian velocity estimates obtained by FGGE drifters in the Labrador Current. J. Atmos. and Oceanic Tech. 14, 292-307.

Valle-Levinson, A. and J. O'Donnell, 1997. Tidal Interaction with buoyancy driven flow in a coastal plain estuary. Coastal and Estuarine Studies, Vol. 53, 265-281.

O'Donnell, J. 1997. Observations of near-surface currents and hydrography in the Connecticut River plume with the SCUD array. J. Geophys. Res. (Submitted)

Li, C. and J. O'Donnell. 1997. Tidally driven residual circulation in shallow estuaries with lateral depth variations. J. Geophys. Res. (Submitted)

O'Donnell, J., A.A. Allen and D.L. Murphy. 1997. An assessment of the errors in Lagrangian velocity estimates obtained by FGGE drifters in the Labrador Current. J. Atmos. and Oceanic Tech. (In press)

Torgersen, T., K.K. Turekian, N. Tanaka, V.C. Turekian, E. DeAngelo and J. O'Donnell. 1996. Ra distribution in surface and deep water of Long Island Sound. Cont. Shelf Res. 16(12): 1545-1559.

O'Donnell, J. 1993. Surface fronts in Estuaries: A review. Estuaries 16(1): 12-39.
Mason, R.P., J. O'Donnell and W.F. Fitzgerald. 1993. Elemental cycling within the mixed layer of the equatorial Pacific ocean. In: C.J. Watras and J.W. Huckabee (eds.), Mercury as a Global Pollutant. Lewis Press, Chelsea, MI.

O'Donnell, J. and P.F. Linden. 1991. Free surface effects on the spinup of fluid in a rotating cyclinder. J. Fluid Mech. 232: 439-453.

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