Global Ice-Ocean Modeling
and Assimilation System (GIOMAS)
ice data are produced by GIOMAS, which consists of a global Parallel
Ocean and sea Ice Model
and Rothrock 2003)
with data assimilation capabilities. The POIM is formulated in a
generalized orthogonal curvilinear
coordinate (GOCC) system and designed to run on computers with a
processor or massively parallel processors. The POIM couples the Parallel Ocean
with a thickness and enthalpy distribution (TED) sea-ice model.
POP model is developed
at the Los Alamos National Laboratory.
model is a dynamic thermodynamic model that also
explicitly simulates sea-ice ridging. The model originates from
Thorndike et al. (1975) thickness distribution theory and is
enriched by enthalpy distribution theory (Zhang
and Rothrock, 2001). It has 8
categories each for ice thickness,
ice enthalpy, and snow.
This multicategory TED model consists of seven main components: a
viscous-plastic ice rheology that determines the relationship
ice internal stress and ice deformation (Hibler 1979), a
redistribution function that determines ice ridging (Thorndike et
1975; Rothrock, 1975; Hibler, 1980), a momentum equation that
determines ice motion, a heat equation that determines ice
and ice temperature, an ice thickness distribution equation that
conserves ice mass (Thorndike et al. 1975; Hibler, 1980), an ice
enthalpy distribution equation that conserves ice thermal energy (Zhang
and Rothrock, 2001), and a snow
thickness distribution equation that conserves snow mass (Flato
Hibler, 1995). The ice momentum equation is solved using Zhang
model that employs a line successive relaxation technique with a
tridiagonal matrix solver, which has been found to be particularly
useful for parallel computing (Zhang
and Rothrock, 2003). The heat equation
is solved over each ice
thickness category using a modified three-layer thermodynamic
ice concentration data are assimilated in GIOMAS using
the Lindsay and Zhang (2005) assimilation procedure. The
based on “nudging” the model estimate of ice
concentration toward the observed concentration in a manner that
ice extent and minimizes the effect of observational errors in the
the ice pack.
configuration of the finite-difference grid of GIOMAS is
dimension of the model is 360×276. In the southern hemisphere the
model grid is based on a spherical
coordinate system. In the northern hemisphere the
model grid is a stretched GOCC grid with the northern grid pole
displaced into Greenland. This allows the model to have its
resolution in the Greenland Sea, Baffin Bay, and the eastern
Archipelago, and therefore a good connection between
the Arctic Ocean and the Atlantic
Ocean via the Greenland-Iceland-Norwegian (GIN) Sea and the
Sea. The model was driven by the NCEP/NCAR reanalysis data.
D. A. Rothrock, G. A. Maykut, and R. Colony, 1975:
The thickness distribution of sea ice. J. Geophys. Res., 80,
Hibler, W. D.
1979: A dynamic thermodynamic sea ice model. J.
Phys. Oceanogr., 9, 815-846.
Hibler, W. D.
1980: Modeling a variable thickness sea ice
cover. Mon. Wea. Rev., 108, 1943-1973.
Flato, G. M.,
W. D. Hibler, III, 1995: Ridging and strength in
modeling the thickness distribution of Arctic sea ice. J. Geophys.
Res., 100, 18,611-18,626.
2000: A reformulated three-layer sea ice model. J.
Atmos. Ocean. Tech., 17, 525-531.