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"Developmental version of CRCM5/GEM3, CRCM6/GEM5"
"MRCC5/GEM3, MRCC6/GEM5 en développement"
Model grids
Global and regional grid types
GEM5 supports rotated lat-lon grids:
- global uniform
- global YinYang (two LAM grids, each covering a little more than half the globe, overlapping like a tennis ball)
- regional LAM (Limited Area Model) grids
LAM grid areas
For LAM grids we distinguish three main regions:
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The free area contains only the model results. Usually, this is the grid used for the model output.
Model levels
Vertical model-level structure
| Vertical model-level structure showing ζ levels as functions of pressure for values below 200 hPa (where the surface is at sea level) in a typical operational configuration. A sinusoidal mountain extending to 600 hPa in the center of the domain demonstrates the compaction of levels on high terrain. (left) The rectification coefficients are rmin = rmax = 4.5; (right) rmin = 2 and rmax = 100 provide a much faster rectification. Citation: Monthly Weather Review 142, 3; 10.1175/MWR-D-13-00255.1 |
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Grid points
Grids of GEM version 4 and up are horizontally (Arakawa C-grid) and vertically (Charney–Phillips) staggered.
Source code
The source code of GEM consists of the dynamics and the physics plus several libraries.
- gemdyn - Dynamics:
Takes care of domain, MPI, processor topology, model configuration, domain decomposition, model geometry
Main loop over timesteps (in gem_run), input, output, initialization
Horizontal advection (also of tracers)
Calls the physics
Main routine: gemdm.F90 - rpnphy - Physics:
gemdyn modelutils rmn rpnphy massv rpncomm vgrid