Global Parallel Experiment Log

Experiment Name

GSI hybrid retrospective 15 June 2005-5 November 2005

Parallel Slot

PRY

Control Slot

GFS

Start date of parallel experiment

2005/06/15

End date of parallel experiment

2005/11/05

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.
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 complete results 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

Effect of GSI hybrid on hurricane forecasts by Morris Bender

Forecast tracks of hurricanes (AVN0 opr. GFS; PARY GSI hybrid GFS; G2006 GFDL 2006 with AVNO; GHYB GFDL 2006 with PARY) by Morris Bender

Forecast East Pacific tracks of hurricanes (AVN0 opr. GFS; PARY GSI hybrid GFS; G2006 GFDL 2006 with AVNO; GHYB GFDL 2006 with PARY) by Morris Bender

Summary of statistics by Glenn White

Conclusion

GSI hybrid improved hurricane tracks for both GFS and GFDL models in 3-5 day forecasts in the Atlantic (Morris Bender)
500 hPa heights slightly better in pry in Northern Hemisphere (.01 anomaly correlation day 5), slightly worse
in Southern Hemisphere (.006 anomaly correlation day 5); rms vector wind error in pry at 200 and 850 hPa in tropics reduced
GSI hybrid precipitation over continental US less positive bias, more skill
compared to radiosondes, GIS hybrid temperatures warmer, temperature forecasts improved in lower troposphere
in Southern Hemisphere and tropics, improved in upper troposphere tropics, forecast heights fit radiosondes significantly better
bias of 200 hPa winds over East Asia substantially reduced in GSI hybrid, GSI hybrid analysed moisture closer to radiosondes

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