IFS Documentation front page

I Observations
II Assimilation
III Dynamics
IV Physics
V Ensemble
VI Technical
VII Waves

4.3 Performance

The following performance figures relate specifically to the operational version of the model run at horizontal resolution T213 with 31 levels on the 16-processor Cray Y-MP C90. With the model time-step set at 15 minutes the total CPU time per forecast day would be about 1.5 hours on a single processor, the corresponding elapsed time (excluding the post-processing) being 7 minutes when the work is shared amongst 16 processors. This represents a sustained computation speed of about 3.5 gigaflops floating-point operations per second). The memory requirements are 49 Mwords of central memory plus 70 Mwords of secondary storage. Multitasking using 16 processors provides a speed-up factor of 13 compared with using a single processor. A typical operational 10-day forecast, including all the post-processing, takes 2 hours of elapsed time.