Global Parallel Experiment Log

Experiment Name
GSI hybrid real-time
Parallel Slot
Control Slot
Start date of parallel experiment
End date of parallel experiment
Implementation date if any
May 1, 2007
Environmental Modeling Center scientists
whole GlobMob
Abstract (including Motivation, Hypothesis and Method)
Analysis changes (Russ Treadon, Daryl Kleist, John Derber)
--Replace Spectral Statistical Interpolation (SSI) analysis system with Gridpoint Statistical Interpolation (GSI) analysis system.
--Use of increased observations including:
----Full resolution AIRS (every field of view form of AIRS rather than only center spot AIRS (used in oeprational GFS)
----A problem in COSMIC GPSRO was corrected on March 5, 2007.
Model changes
--Modify sigma coordinate system to a hybrid sigma-pressure coordinate system
--Updated GFS radiation module (Yu-Tai Hou)
----overall restructuring of radiation related programs to help future development and upgrade
----In RRTM1-LW, minor upgrade of emissivity coefficient. Rare gas absorption effect turned on
----In aerosol calculation, vertical sigma based structure changed to pressure based structure
----Minor bug correction in cloud related calculation
----Performance of new radiation very close to operational model
Product changes
--Add 30 records to surface flux fields
--Change output of GDAS from 3-hourly to hourly
--Model to native output file will change from a spectral binary file to a hybrid spectral binary file
Questions? Contact or
Experiment changes log
Implementation changes list
Product changes list
Background links
Evaluation of parallel results
Skill evaluation of real-time parallel Apr 12 by Glenn White
Skill evaluation of real-time parallel Mar 29 by Glenn White
Daily forecast maps by FangLin Yang
Daily forecast maps of 500 hPa height for many models by FangLin Yang
Daily forecast statistics by Pete Caplan
Daily forecast statistics by FangLin Yang
Verification against sondes and aircraft by Suru Saha
GFS PRX case study April 1 by Richard Pasch
Biases of operational and parallel GDAS and Guess against observations by Brad Ballish
Verification of precipitation over continental United States 000UT by Y. Zhu
Verification of precipitation over continental United States 1200UT by Y. Zhu
Clouds and radiation verification and comparison for March 2007 by Ken Campana
Clouds and radiation verification and comparison for Feb 2007 by Ken Campana
parallel skill in extratropics very close to operational
parallel slightly more skill in precipitation forecasts over continental United States
parallel improves tropical wind forecasts below 300 hPa, worse wind forecasts above 300 hPa
parallel much less negative bias in Asian jet
parallel short-range forecasts less rms error against analyses
parallel short-range height forecasts significantly closer to radiosondes
parallel winds closer to radiosondes
parallel forecast winds fit ACARS, aircraft winds better between 200 and 150 hPa
parallel extratropical temperatures closer to radiosondes
parallel analysed moisture closer to radiosondes
Detailed comments
Total cloud slightly less in the parallel and may be due to less stratus.
High cloud is a bit more in the parallel.
Radiation changes driven by cloud changes: day 1, SW absorption larger in parallel
which may help force warmer land surface in parallel (sfc LW up in parallel
Cloud correlation and bias differences are small, but low cloud in parallel
seems to have less correlation with USAF clouds and has negative bias.
These are small differences. Day 1 differences seem larger than day 5 differences. (Ken Campana)
Retrospective experiments
15 June 2005-5 November 2005 retrospective by Russ Treadon and Daryl Kleist
31 July 2006-5 November 2006 retrospective by Russ Treadon and Daryl Kleist
24 October 2006-5 February 2007 retrospective by Russ Treadon and Daryl Kleist

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Page Last Modified: March 26, 2007