Global Parallel Experiment Log

Experiment Name

T170 L42 MRF Forecast

Parallel Slot

PRX

Control Slot

MRF

Start date of parallel experiment

1999/06/30/00

End date of parallel experiment

2000/01/24/12

Global Modeling Branch scientists

Mark Iredell

Abstract (including Motivation, Hypothesis and Method)

The T170 L42 "Final" Global Data Assimilation System (FNL GDAS) and daily Medium Range Forecast (MRF) are run on the new IBM SP. The data assimilation system started on July 22; until then the T170 L42 forecast was initialized from the operational T126 L28 analyses. The T170 L42 analysis fits the observations much better than the 1998 implementation; this analysis is essentially the same version as the T170 L42 parallel tests run on the Cray in late 1998 and early 1999. The T170 L42 model is the same model that was run at this resolution in 1998 (and in parallel in early 1999). A digital filter initialization half-period of 3 hours is used. The forecast remains at T170 L42 resolution for 7 days. Then the 6.5 day forecast is truncated to T62 L28 and run out to 7 days again with a 3-hour digital filter initialization half-period. This new 7-day forecast is used to run the MRF extension at T62 L28 out to 16 days. This procedure at day 7 is designed to reduce the convective precipitation spinup noted when the resolution is reduced. This is the first global parallel on the new IBM SP.

Itemized source or script changes

No scientific changes to the model, but

All new source and scripts are used on the IBM SP.

Itemized product or file changes

The order of the fields in pressure GRIB file has been shifted slightly.

New fields in the pressure GRIB file

CAUTION: New forecast time units used in the pressure GRIB file

Sample inventory for pressure GRIB file

Sample inventory for pressure GRIB file for forecast hour 264

All fixed files are copied to or regenerated on the IBM SP.

Experiment changes log

Evaluation of parallel results

Daily forecast maps by Pete Caplan

D+8 and week 2 maps by Jae Schemm (CPC)

D+8 and week 2 scores by Jae Schemm (CPC)

Anomaly correlation score comparisons by Yuejian Zhu

February 1999 T170 vs T126 fits to obs by Suranjana Saha

February 1999 T170 vs T126 fits to obs by Yuejian Zhu

February 1999 T170 vs T126 model diagnostics by Glenn White

August 1998 T170 vs T126 fits to obs by Suranjana Saha

August 1998 T170 vs T126 fits to obs by Yuejian Zhu

August 1998 T170 vs T126 model diagnostics by Glenn White

August 1998 T170 vs T126 more diagnostics by Glenn White

Conclusion

Draft Technical Procedures Bulletin (TPB) by Caplan and Pan

Operational implementation on 2000/01/24/12.

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