Bias Correction Current Status of Implementation

1
Bias Correction Current Status of Implementation

• Bo Cui1, Zoltan Toth2, Yuejian Zhu2, Richard
  Verret3, David Unger4
• 1SAIC at Environmental Modeling Center, NCEP/NWS
• 2Environmental Modeling Center, NCEP/NWS
• 3Canadian Meteorological Centre, Meteorological
  Service of Canada
• 4Climate Prediction Center, NCEP/NWS
• Acknowledgements
• Stéphane Beauregard, Richard Wobus, Dingchen
  Hou, Malaquias Pena

2
NCEP Ensemble

• NCEP Ensemble Bias Correction
• Bias estimation correction jobs are implemented
  in NCEPs parallel job stream on March 13, 2006
• cold start all Kalman-filter type algorithms are
  set up not to fail by using
• default value ( such as zero) for all variables
  of concern if prior
• information is not available
• Daily schedule for bias-correction jobs in
  parallel stream computer usage
• bias estimation 4 cycles per day, 00z, 06z,12z
  and 18z, 10 minutes/1 cpu
• bias correction 4 cycles per day, run
  simultaneously with operational forecast,
• 1 hr./1 cpu
• Current work web display of NAEFS bias-corrected
  ensemble graphical products
• difference between CDAS reanalysis and the
  operational analysis
• comparison plots bias vs. raw ensemble mean,
  spread vs. bias-corrected
• ensemble mean

3

CMC Ensemble

• CMC Ensemble Post-Processing
• Tests with new CMC ensemble dataset ( 06 hr
  outputs up to 16 days twice a day) were done.
  New CMC ensemble post-processing are implemented
  in NCEPs operational stream on March 1, 2006
• problem related with common scaling factor when
  encoding u/v fields at MSC forecasts was fixed (
  Yuejian Zhu Stephen Gilbert )
• cost for interpolation 22 minutes / 17 cpu for
  bi-cubic option
• Current work rewrite CMC's post programs, which
  are good for enspost file structure. The new
  program will generate pgrba file format directly,
  which will be used for the CMC ensemble bias
  estimation and correction
• CMC Ensemble Bias Correction
• Codes/scripts available, need tests when data (
  pgrba ) available
• Need MSC 06Z 18Z analysis to generate the
  difference between CDAS and MSC analysis, which
  will be used for climate anomaly forecast