AOS Faculty Profile
Lecturer, Ph.D. University of Washington
Address: 351 GFDL
Phone: (609) 452-6508
Email: Robert.Hallberg at noaa.gov
Ocean Dynamics and Numerical Ocean Model Development
The ocean is sufficiently complicated that a comprehensive understanding the ocean’s role in climate requires the use of numerical models that accurately represent the ocean’s dynamics on timescales from tidal to millennial. My research is focused on developing such models and using them to understand key aspects of the ocean’s dynamics.
The ocean is known observationally to exhibit very weak mixing across interior density surfaces. Much of my research effort is focused on developing a density-coordinate ocean model that robustly respects this property. While this approach constrains cross-density-surface mixing by construction, it introduces unique challenges in representing the non-conservative aspects of the ocean’s thermodynamics. Recent foci for me have included the accurate treatment of the ocean’s nonlinear equation of state and the representation of vigorously entraining overflow gravity currents in ocean models.
In addition, I have recently been studying the role of eddies in the Southern ocean’s dynamics and especially in the stability of the southern upwelling branch, using increasingly realistic high resolution numerical studies. These studies demonstrate the importance of the mesoscale ocean dynamics for constraining the global ocean circulation.
Some Recent Publications:
Hallberg, R., 2005: A thermobaric instability of Lagrangian vertical coordinate ocean models. Ocean Modelling, 8, 279-300.
Legg, S., R. W. Hallberg, and J. B. Girton, 2005: Comparison of entrainment in overflows simulated by z-coordinate, isopycnal and non-hydrostatic models. Ocean Modelling, 11, in press.
Simmons, H. L., R. W. Hallberg, and B. K. Arbic, 2004: Internal wave generation in a global baroclinic tide model. Deep-Sea Research II, 51, 3043-3068.
Hallberg, R., and A. Gnanadesikan, 2001: An exploration of the role of transient eddies in determining the transport of a zonally reentrant current. J. Phys. Oceanogr., 31, 3312-333