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Other models running at the same time describe energy, moisture and momentum fluxes from the underlying land or sea surfaces.  These are:

• a Land-Surface Model the land-surface model (HTESSEL).
• the lakes , including a program for lakes and coastal waters model (FLake) that itself .  This provides information on temperature changes and the development, decay and movement of areas of ice.  The forecasts of ice which cover impact upon heat flux and albedo.
• the Wave Model (ECWAM)
• the Dynamic Ocean Model (NEMO), including .  This includes a program (LIM2) which provides information on the development, decay and movement of areas of sea ice.  The forecasts of ice which cover impact upon heat flux and albedo.
  
  

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Basic prognostic equations are efficiently processed in spectral space and need only a relatively small proportion of computer time required for a forecast.  But many processes are computed in grid point space (e.g. rainfall) and this requires a larger, but relatively modest, proportion of computer time.   Processes in grid-point space, and in spectral space, and in the associated spectral transforms, are broadly similar in computer time but .  However, the necessary transpositions between spectral and grid point spaces is are a significant computing overhead.  Semi-lagrangian computations also take up an important proportion of processing time.

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