GFDL - Geophysical Fluid Dynamics Laboratory

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Robert Hallberg

Oceanographer at NOAA's Geophysical Fluid Dynamics Laboratory.

Formerly of Prior Lake, the University of Chicago, and the University of Washington School of Oceanography.

Current Work

In September, 2012, GFDL publicly released the "Generalized Ocean Layer Dynamics" (GOLD) model. GOLD is an extension and generalization of the capabilities of the earlier Hallberg Isopycnal Model (HIM) (for details of HIM see the HIM web page).  GOLD is the physical ocean model basis of GFDL's ESM2G Earth System Model (click here for CMIP5 results from ESM2G). GOLD has a variety of test cases, ranging from idealized configurations for Geophysical Fluid Dynamics Studies to fully realistic coupled climate models.

GFDL is now focusing all of its ocean model development efforts on a single model, MOM6.  MOM6 will be built upon the GOLD dynamic core, and embody both the GOLD capabilities and all of the best features of MOM4/5. One of the first applications of MOM6 will be the development of a moderately high resolution (1/4 degree) C-grid, Z*-coordinate coupled configuration as the likely ocean component of GFDL's next generation coupled climate model (tentatively named CM4).  A public release of MOM6 is intended to follow shortly upon the successful development of this configuration.

Through the project Modeling Eddies in the Southern Ocean (MESO), we have examined the role of transient eddies in the dynamic and watermass balances in the Southern Hemisphere with a series of increasingly high resolution primitive equation model simulations using HIM. The profound qualitative impact of changing resolution can be seen in this 19Mb animation of the surface speed from two of the MESO models. Full details are given in Hallberg and Gnanadesikan (2006).

We are engaged in a series of studies comparing the mean state and climate response of GFDL's two Earth System Models, ESM2M and ESM2G, which differ only in their ocean component. We see, for instance a systematic 18% difference between ESM2M and ESM2G in the global mean steric sea level rise that these two models predict (Hallberg et al., 2013), with much of these differences in steric sea level rise arising from differences between the models' spun-up ocean states.

We are working to dynamically couple our highest resolution global ocean models to continental scale ice-sheet models, including smoothly moving grounding lines and dynamic reshaping of the ice-shelf cavities.  This capability has already been demonstrated in idealized settings by Goldberg et al. (2012a, 2012b).

I am actively involved an Ocean Climate Process Team working on Internal Wave Driven Mixing, and in the past I was an active participant in two other Climate Process Teams - one studying Gravity Current Entrainment, and the other examining Eddy-Mixed Layer Interactions. These teams aim to improve the the representation of these processes in climate-scale models, based on the best understanding that can be obtained from observations, process studies, and theory.

Bibliography

Click here for my bibliography

Contact Info

Dr. Robert Hallberg
NOAA/GFDL
Princeton University
Forrestal Campus, U.S. Route 1
201 Forrestal Road
Princeton, NJ 08542

E-mail: Robert.Hallberg@noaa.gov
FAX: (609) 987-5063
Work Phone: (609) 452-6508