Recent Upgrades and Plans for the NOAANCEP Short Range Ensemble Forecast SREF System Jeff McQueen, J

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Recent Upgrades and Plans for the NOAA/NCEP Short
Range Ensemble Forecast (SREF) System Jeff
McQueen, Jun Du, Binbin Zhou, Geoff Manikin, Brad
Ferrier and Geoff DiMego Wednesday, November
11, 2009
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SREF Team

• System Integration/Operations Jun Du
• Physics Diversity Configuration B. Ferrier
• Product Generation/Visualization
• Standard Suite Binbin Zhou, Jun Du
• Aviation, Energy Binbin Zhou
• Severe Weather G. Manikin, D. Bright
• Verification
• Model to Observations (Det/Prob) H. Chuang
• Model to analysis (Det/Prob) B. Zhou
• Case Studies G. Manikin, R. Grumm
• Calibration
• Bias Correction J. Du, B. Coi
• Bayesian Model Averaging Mark Raulston
• High Res Ensembles (WRF) G. DiMego, D. Jovic,
  E. Rogers, H. Chuang
• Ensemble Transforms (Future) M. Wei, Z. Toth
• Training B. Bua

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Outline

• Improved SR-Ensemble Prediction Systems
• NCEP Short Range Ensemble Forecasts (SREF)
• High Resolution Window Weather Reseach and
  Forecast System (WRF) Ensemble
• Improved Deterministic and Probabilistic Products
• Higher Fidelity ? Capture smaller scale features
• Improved Accuracy
• Improved probabilistic information to help
  quantify forecast uncertainties
• Bias Correction and Bayesian Model Averaging
• Visualization
• Verification

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Ensemble Modeling System Goals

• Improved probabilistic products for NWS mission
  forecasts (Severe storms, Aviation, Hydromet,
  ocean, tropical, Energy, Dispersion)
• Quantify Uncertainty for Each Forecast Run
• High Confidence good agreement between
  forecasts?
• Improved Spread-Skill relationship Information
• System variance System Mean Squared Error
• Less clustering among ensemble members(more
  spread)
• Improved or similar skill as determined from
  ensemble mean and probabilistic skill scores for
  1-3 day forecasts (Skill scores, Sharpness of
  probabilistic forecast)
• Temperatures, winds, moisture
• Precipitation
• Upper-level winds, heights

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Recent SREF Improvements

• Increased Resolution
• 48 km to 32 km horizontal resolution
• Increased to 60 levels in Eta model Members
• Enhance SREF Physics Diversity
• Various Cloud Physics and Convective
  Parameterization Schemes
• Scaled Breeding System
• Control Unrealistically Large Initial Condition
  (IC) Perturbations in cold season
• Increase IC perturbations in warm season
• Upgrade 10 Eta members to latest operational
  version (Impr. Land sfc model, cloud-rad effects)
• Upgrade 5 Regional Spectral Model (RSM) Members
  with GFS Physics and Computational Schemes

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SREF Current System Physics Members
Model Res (km) Levels Members Cloud
Physics Convection RSM SAS 40 28 Ctl,n,p
GFS physics Simple Arak-Schubert RSM
RAS 40 28 n,p GFS physics Relaxed
Arak-Schubert Eta-BMJ 32 60 Ctl,n,p Op
Ferrier Betts-Miller-Janjic Eta-SAT
32 60 n,p Op Ferrier BMJ-moist
prof Eta-KF 32 60 Ctl,n,p Op
Ferrier Kain-Fritsch Eta-KFD 32 60 n,p Op
Ferrier Kain-Fritsch with
enhanced detrainment
Adjust conv. Params to account for known
biases e.g Biases in Convective initiation
timing Implemented into NCEP Operations on
August 17, 2004
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Corrections to Improve Initial System Performance

• Run reduced physics-diversity system evaluate
  Modified SREF system
• Develop and test scaled IC breeding code
• breeding perturbation using WRF scaled
  perturbation system. Used average 850 mb T
  standard deviation (0.5 C) to scale IC
  perturbations.
• IC perturbation scale 0.5/ ?
• Where ?Fneg-Fpos of the 12 hour domain avg 850
  mb T forecast

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Ensemble Products
Prob. THIgt75 F
Mean/Spread Surface Pressure
Prob. Clr Skies
Mean/Spread 2m Temperature
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SREF Deterministic Results Surface CONUS Errors
by Forecast hr (Summer 2004)
2 m Temperature Error
2 m Temperature Bias
2 m Temperature Error
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SREF Deterministic Results Upper-Level 48 h
RMSE (June 12-July 11, 2004)
U.L.Temperature
U.L.Wind
U.L.RH
Heights
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SREF Probabilistic Results Spread Plots (June
12-July 11, 2004)
SLP
500H
850T
850U
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SREF Probabilistic Results 12h Precipitation-
0.1 threshold (June 12-July 11, 2004)
12 h qpf RPSS
12 h qpf Spread
RPSSRelative Probabilistic
Skill Score
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SREF Probabilistic Results Ranked Histograms 63
h forecasts (June 12-July 11, 2004)
Operational Experimental
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SREF Aviation ProjectLow Level Wind Shear
Uncertainty
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SREF Warm Season Case StudyJuly 22, 2004 09 Z
Forecast (51h Forecast)
Operational
Experimental

Increased spread in Enhanced physics- Diversity
system
Precipitation Spread (inches)
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SREF Warm Season Case StudyJuly 22, 2004 09 Z
Forecast (51h Forecast) Prob. Precipgt1 in 48 h
Operational
Observed 48h Precip

Experimental
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SREF Warm Season Case StudyJuly 25, 2004 09 Z
Run (12 h forecast)
SREF-48 km
SREF-32 w/ Physics Diversity

20C 2m Temp
20C 2m Temp
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SREF Cold Season Case StudyFebruary 26, 2004 21
Z Run (12 h forecast)
SREF 45 hr Forecast
Eta-12 km 48 hr
Verification
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SREF Cold Season Case Study
ETA-BMJ
ETA-KF
RSM-SAS
CTL
CTL
CTL
P1
P1
P1
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Improved System Postprocessing

• Bias Correction
• Simple running average correction based on
  previous week error
• Regime Dependent Correction
• Weight corrections for each day based on current
  forecasts correlation w/ previous forecast
  errors
• Bayesian Model Averaging
• Calibrate system PDF (variance) by training and
  weighting ind. Member PDF
• Train member PDF against observations for past
  month

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Static Bias Correction day to day rmse reduction
(45h fcst)
(model RSM)
SLP
500H
850T
850U
850RH
250U
Oct. 3 10, 2004 16 cycles
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Original Error (Temperature, 63hr fcst)
Estimated flow-dependent bias
Error after correction
Error changes
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Summary

• Deterministic results generally positive
• Significant reduction of low level errors
  Increased physics diversity resolution and
  scaled breeding improves system spread
• Improved Diversity
• Strongest impact on sensible wx and in Warm
  Season
• Additional scenarios captured
• Initial Condition perturbations capture synoptic
  scale uncertainties well
• Scaled breeding controls unrealistic system
  spread

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Weather Research and Forecasting

• End-to-end Common Modeling Infrastructure
• Observations and analysis
• Prediction model
• Post-processing, product generation and display
• Verification and archive
• For the community to perform research
• For operations to generate NWP guidance
• USWRP sponsorship - many partners NCAR, NCEP,
  FSL, OU/CAPS, AFWA, FAA, NSF and Navy
• Initial NCEP implementation in NCEP HiResWindow
  (HRW) on Sept. 21, 2004
• Ensemble approach to be taken instead of
  single-run deterministic approach (6 member
  system in fy05)

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HiResWindow Fixed-Domain Nested Runs

• Users want routine runs they can count on at the
  same time every day
• 00Z Alaska-10 Hawaii-8 km
• 06Z Western-8 Puerto Rico-8
• 12Z Central-8 Hawaii-8
• 18Z Eastern-8 Puerto Rico-8
• This gives everyone a daily high resolution run
  when fewer than 2 hurricane runs needed

http//www.emc.ncep.noaa.gov/mmb/mmbpll/nestpage/
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WRF Improved cloud forecasts downwind of
mountains
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HiResWindow Plans
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• SREF Challenges
• SREF Configuration
• Impact of IC perturbations vs. model physics
  diversity
• Physics diversity (Application dependent ?)
• Role of Land Sfc, PBL, Precip processes
• Membership vs horizontal resolution
• (2) Improved IC perturbations
• ET, Singular Vectors, Multi-analyses
• (3) Impact of lateral boundary conditions
• (4) Single model EPS vs. multi-model EPS
• (5) Improved Post processing such as bias
  correction,
• spread and PDF calibration

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SREF Planned Upgrades

• 2005
• System
• Run SREF 4 times per day (03, 09, 15 and 21 UTC)
  at 25 km
• Add 6 WRF members (some w/ GFS initial
  conditions)
• Use Higher resolution GFS w/ MREF anomolies for
  SREF Lateral Boundary Conditions
• Products
• Improved and new products (Convective, Aviation,
  Tropical, Energy)
• Output SREF forecasts for Alaska and Hawaii
• Add SREF mean hrly sounding BUFR files
• Implement Common WRF post-processor for all
  members
• Post Processing
• Implement Grid Based Bias Correction
• Develop Confidence Factors for forecasts
• Verification
• Improve Probabilistic NCEP Forecast Verification
  System (FVS) Capabilities (event based stats)

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SREF Beyond 2005

• Test Global Ensemble Transform Techniques
• Increase membership and diversity
• Add Land surface, PBL perturbations
• Multi-analysis IC (eg EDAS, GSI)
• 50 members, 10 km (2008)
• Regime dependent bias correction
• Implement Bayesian Model Averaging
• Improved Products/Applications
• Dispersion, Air Quality
• Energy, transportation
• All WRF based membership (multi-core, multi-IC,
  multi-physics suites)
• Relocatable High Res ensemble
• VSREF Very Short Range Ens. Forecasts for
  Aviation 3 hrly updates (6-24 h forecasts)

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Torino OlympicsA breeding ground for
Multi-center SR-EPS Evaluation
8 member multi-model,physics,bred ICs

• C1 WRF-NMM/Ncep Phys Ctl, p1, n1,p2,n2
• C2 WRF-MASS/Ncar Phys Ctl, p3,n3,p4,n4
• CTL 4 km, 1000x1000 km
• Perts 8 km, 2000x2000 km
• Du, 2004 hybrid technique
• Add spread from perturbed members to high res
  ctls
• ? How much diversity given by physics diffs
• ? How much diversity given from core diffs
• ? Alternative Multi-analysis members
• C1X, C2X initalized w/ GFS ICs

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BACKUPS
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Dissemination

• Mean, spread, probability files on NCEP FTP site
• NCEP/EMC web graphics
• Mean, spread, probs, Individual members,
  profiles,
• NCEP/SPC Convective probabilistic products
• Mean, spread plots are being added to NCEP
  Operational web page
• WFO AWIPS Scheduled for Build 7 (April 2005)

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WRF/Nonhydrostatic Mesoscale ModelFeature
Comparison With Meso Eta