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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