Global Parallel Experiment Log

Experiment Name
GSI hybrid retrospective 24 Oct. 2006-5 Feb. 2007
Parallel Slot
PRY
Control Slot
GFS
Start date of parallel experiment
2006/10/24
End date of parallel experiment
2007/02/05
Implementation date if any
May 1, 2007
Environmental Modeling Center scientists
whole GlobMob
Abstract (including Motivation, Hypothesis and Method)
Analysis changes
--Replace Spectral Statistical Interpolation (SSI) analysis system with Gridpoint Statistical Interpolation (GSI) analysis system.
--Use of increased observations including:
----Full resolution AIRS
----COSMIC GPSRO
Model changes
--Modify sigma coordinate system to a hybrid sigma-pressure coordinate system
--Updated GFS radiation module
Questions? Contact Glenn.White@noaa.gov or Mark.Iredell@noaa.gov
Background links
Evaluation of parallel results
Summary of final statistics by Glenn White
Forecast statistics by Russ Treadon
Precipitation scores over continental United States by Russ Treadon
Verification against sondes and aircraft by Russ Treadon and Suru Saha
Summary of statistics by Glenn White
Because of problems in processing COSMIC GPS data, the winter retrospective was rerun. Results are evaluated below.
The pry is the original run and the pryc is the corrected run.
Forecast statistics by Russ Treadon
Precipitation scores over continental United States by Russ Treadon
Verification of operational and pryc against sondes and aircraft by Russ Treadon and Suru Saha
Verification of pry and pryc against sondes and aircraft by Russ Treadon and Suru Saha
Verification of T2m, 2m rh, 10m wind and precipitation over continental United States by Helin Wei
Conclusion
500 hPa heights slightly better in GSI hybrid in NH (.012 anomaly correlation day 5),
slightly worse in SH (.004 anomaly correlation day 5)
rms vector error reduced in tropical winds; large improvement in 850 hPa tropical winds
GSI hybrid precipitation over continental US slightly more skill than operational
GSI hybrid analysed tropical winds closer to radiosondes; forecast tropospheric winds
closer to radiosondes than operational
bias, rms vector error of 200 hPa winds over East Asia substantially reduced in GSI hybrid
GSI analysed and forecast extratropical temperatures closer to radiosondes than operational
analysed tropical temperatures further from radiosondes, stratospheric temperatures closer to radiosondes
forecast heights fit radiosondes significantly better in GSI hybrid
GSI hybrid analysed moisture closer to radiosondes
Specific comments
* 2-m temp is warmer compared with OPS. This is consistent with Suru's fits over North America.
* The warmer temp reduces the daytime cool bias
but increases the nighttime warm bias over the east CONUS. It
also introduces the nighttime warm bias over the west CONUS.
* 2-m RH is slightly higher in case pryc.
* It is a wash for case pryc
* Little change is found in 10-m wind speed for both cases.
* The improvement in the precip is impressive
* The threat score is higher except the first
threat over the whole CONUS. While the precip score is
improved in the east CONUS, it is degraded in the west CONUS.
Overall I like the performance of PRY especially the improvement of
precipitation. (Helin Wei)

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Page Last Modified: March 28, 2007