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Next: 3.14.2 Forcing
Up: 3.14 Held-Suarez Atmosphere MITgcm
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This example demonstrates using the MITgcm to simulate
the planetary atmospheric circulation, with flat orography
and simplified forcing.
In particular, only dry air processes are considered and
radiation effects are represented by a simple newtownien cooling,
Thus this example does not rely on any particular atmospheric
physics package.
This kind of simplified atmospheric simulation has been widely
used in GFD-type experiments and in intercomparison projects of
AGCM dynamical cores [Held and Suarez, 1994].
The horizontal grid is obtain from the projection of a uniform gridded cube
to the sphere. Each of the 6 faces has the same resolution, with
grid points. The equator line coincide with a grid line
and crosses, right in the midle, 4 of the 6 faces, leaving 2 faces
for the Northern and Southern polar regions.
This curvilinear grid requires the use of the 2nd generation exchange
topology (pkg/exch2) to connect tile and face edges,
but without any limitation on the number of processors.
The use of the
coordinate with 20 equally spaced levels
(
, from
to 0
at the
top of the atmosphere) follows the choice of Held and Suarez [1994].
Note that without topography, the
coordinate and the normalized
pressure coordinate (
) coincide exactly.
No viscosity and zero diffusion are used here, but
a
order Shapiro [1970] filter is applied to both momentum and
potential temperature, to remove selectively grid scale noise.
Apart from the horizontal grid, this experiment is made very similar to
the grid-point model case used in Held and Suarez [1994] study.
At this resolution, the configuration can be integrated forward
for many years on a single processor desktop computer.
Next: 3.14.2 Forcing
Up: 3.14 Held-Suarez Atmosphere MITgcm
Previous: 3.14 Held-Suarez Atmosphere MITgcm
Contents
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Massachusetts Institute of Technology |
Last update 2018-01-23 |
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