Chapter 12 - Operational NWP.pdf
Chapter 12 - Operational NWP.pdf
Chapter 12 - Operational NWP.pdf
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Factors that control<br />
model execution speed<br />
• Must wait for most observations to arrive – model “cutoff”<br />
times can be 60-90 minutes.<br />
• For LAMs, must wait for the LBCs<br />
• The time step – requirement depends on numerical<br />
approach, and how conservatively the time step is chosen if<br />
there is a constraint.<br />
• The number of grid points<br />
• The speed of the processors, the number of processors,<br />
and how well the execution time scales with the number of<br />
processors.<br />
• The sophistications of the physics parameterizations<br />
• Make output available as the model is running.<br />
• Execution speed versus user friendliness<br />
• Large I/O loads can slow execution speed.
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