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Record Search Query: ServiceParameters>MODELS>OCEAN GENERAL CIRCULATION MODELS (OGCM)/REGIONAL OCEAN MODELS

HYbrid Coordinate Ocean Model (HYCOM)
Entry ID: RSMAS_HYCOM
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Summary
Abstract: HYCOM (Bleck, 2002) is the hybrid coordinate version of MICOM. While still primarily isopycnic in character, HYCOM allows coordinate surfaces to locally deviate from isopycnals wherever the latter either fold, outcrop, or generally provide inadequate vertical resolution.

The coordinate hybridization approach in HYCOM differs from other generalized coordinate schemes developed over the years in that is does not rely on an analytic formula for specifying the depth of a given grid point. Rather, it assigns each coordinate surface a reference or "target" isopycnal and continually tries to move individual grid points which have become separated from their target isopycnal back to it. As grid points vertically migrate through the fluid, they are subjected to repelling forces from grid points above or below. These "forces" may prevent grid points from reaching their target isopycnal, but they also keep coordinate surfaces from fusing. A "pure" isopycnic model may be viewed as a hybrid model in which the repelling force is set to zero.

HYCOM, like MICOM, is a primitive-equation model containing 5 prognostic equations -- two for the horizontal velocity components, a mass continuity or layer thickness tendency equation, and two conservation equations for a pair of thermodynamic variables, such as salt and temperature or salt and density.

In hydrostatic models of geophysical fluids, the mass continuity equation typically is used to infer the vertical fluid velocity from the horizontal mass flux divergence. In models where coordinate surfaces are allowed to move vertically, the vertical fluid velocity can be decomposed into the movement of the coordinate surface and the fluid velocity relative to this surface. The centerpiece of HYCOM is a "grid generator" that specifies how this decomposition is to be done at any given time and grid location. The grid generator takes into account two factors: the distance by which a coordinate surface would have to travel to merge with its target isopycnal, and the distance by which a coordinate surface can move without bumping into its nearest neighbor. By treating the sea surface as one of these neighbors, the algorithm prevents coordinate surfaces from vanishing at the geographic location where their target isopycnals outcrop; instead, HYCOM allows them to continue as fixed-depth surfaces that can be put to good use in modeling vertical mixing processes in the surface layer.

Bleck, R., 2002: An oceanic general circulation model framed in hybrid isopycnic-Cartesian coordinates. {\em Ocean Modelling, 4}, 55-88.

Related URL
Link: VIEW PROJECT HOME PAGE
Description: Numerical Ocean Model Development at the Rosenstiel School of Marine and
Atmospheric Science.

Link: GET RELATED SERVICE METADATA (SERF)
Description: View Information abou the HYCOM Model's sister model
the Miami Isopycnic Coodinate Ocean Model (MICOM).

Link: VIEW RELATED INFORMATION
Description: The MICOM Model Home Page.

Link: VIEW RELATED INFORMATION
Description: Documentation of HYCOM
Service Citation
Originators: Bleck, R.
Title: HYbrid Coordinate Ocean Model (HYCOM)
Release_Date: 2002
URL: http://www.hycom.org/
ISO Topic Category
ELEVATION
OCEANS
Service Provider
Rosenstiel School of Marine and Atmospheric Science, University of Miami

Service Provider Personnel
Name: RAINER BLECK
Phone: 305-361-4045
Fax: 305-361-4696
Email: rbleck at rsmas.miami.edu
Contact Address:
MPO Div., RSMAS
University of Miami
4600 Rickenbacker Causeway
City: Miami
Province or State: FL
Postal Code: 33149
Country: USA
Distribution Media
Distribution_Media: Online (FTP)
Fees: No Fee
Personnel
RAINER BLECK
Role: TECHNICAL CONTACT
Phone: 305-361-4045
Fax: 305-361-4696
Email: rbleck at rsmas.miami.edu
Contact Address:
MPO Div., RSMAS
University of Miami
4600 Rickenbacker Causeway
City: Miami
Province or State: FL
Postal Code: 33149
Country: USA

SCOTT A. RITZ
Role: SERF AUTHOR
Phone: 301-614-5126
Fax: 301-614-5268
Email: Scott.A.Ritz at nasa.gov
Contact Address:
NASA Goddard Space Flight Center
Global Change Master Directory
City: Greenbelt
Province or State: Maryland
Postal Code: 20771
Country: USA
Publications/References
Bleck, R., and D. Boudra, 1981: Initial testing of a numerical ncean
circulation model using a hybrid (quasi-isopycnic) vertical coordinate. J.Phys. Oceanogr., 11, 755-770.

Bleck, R., and S. Benjamin, 1993: Regional weather prediction with a model combining terrain-following and isentropic coordinates. Part I: Model description. Mon. Wea. Rev., 121, 1770-1785.

Halliwell, G., R. Bleck, and E. Chassignet, 1998: Atlantic Ocean simulations performed using a new hybrid-coordinate ccean model. EOS, Trans. AGU, Fall 1998 AGU meeting.

Large, W. G., J. C. Mc Williams, and S. C. Doney, 1994: Oceanic vertical
mixing: A review and a model with a nonlocal boundary layer parameterization. Rev. Geophys., 32, 363-403.

Large, W.G., G. Danabasoglu, S.C. Doney, and J.C. McWilliams, 1997: Sensitivity to surface forcing and boundary layer mixing in a global ocean model: Annual-mean climatology. J. Phys. Oceanogr., 27, 2418-2447.
Creation and Review Dates
SERF Creation Date: 2003-08-20
SERF Last Revision Date: 2011-05-13
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