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Ensemble-4DWX update: focus on calibration and verification

Ensemble-4DWX update: focus on calibration and verification. Tom Hopson, Josh Hacker, Jason Knievel, Yubao Liu, Gregory Roux, Wanli Wu. Reminder of status in April 2009. Running WRF V3.0.1.1

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Ensemble-4DWX update: focus on calibration and verification

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  1. Ensemble-4DWX update: focus on calibration and verification Tom Hopson, Josh Hacker, Jason Knievel, Yubao Liu, Gregory Roux, Wanli Wu National Security Applications Program Research Applications Laboratory

  2. Reminder of status in April 2009 • Running WRF V3.0.1.1 • Had just finished running E-4DWX for ATC during Dec 2008 and Jan 2009, then returned configuration to DPG • Configured and ran E-4DWX for supporting UT Division of Air Quality • Improved MYJ and YSU PBL height diagnosis and PBL mixing • Added new graphics and improve post-processing flexibility (installation for GMOD and plotting historical case archive) and computing parallelisms • Fully automated calibration just being tested • Calibrated variables: 2-m T National Security Applications Program Research Applications Laboratory ATEC-4DWX IPR, Aug 11-12 2009

  3. Progress since April 2009 (1 of 2) • Improved scripting to manage the computational resources • Increased stations from 26 to 34 (regional) • Calibration hindcast increased from roughly 600 to over 1000 points • Increased hindcast size allows calibration of 2 additional lead-times (36hr, 42hr) • Included new skill measure for ensemble skill-spread relationship • Corrected over-dispersion of calibration process • Calibrated variables: 2-m T, 2-m Td (new) National Security Applications Program Research Applications Laboratory ATEC-4DWX IPR, Aug 11-12 2009

  4. Progress since April 2009 (2 of 2) • Examined results from CAD study at ATC (earlier talk) • Using performance of ensemble members to optimize DPG’s single-model configuration • Submitted proposal for brief paper in BAMS but was rejected. Have not decide whether to revise and resubmit • Continuing to work on scientific paper for MWR • Downtime of HPC (recent): May 13-20, Agami4 failure June 16-18, SGI node July 11-19, power outage caused Agami4 failure July 29 - August 4, Agami4 failure National Security Applications Program Research Applications Laboratory ATEC-4DWX IPR, Aug 11-12 2009

  5. Calibration and verification • Ensemble calibration to correct predicted distribution • Calibration is needed for users capable of decision making with probabilistic guidance. Will be needed for foreseeable future • Verification of different ensemble characteristics is easily completed when performing calibration National Security Applications Program Research Applications Laboratory ATEC-4DWX IPR, Aug 11-12 2009

  6. Calibration: review and recap Calibration (and verification) is now fully-automated Utilizes “persistence” if available 34 sites in and near DPG Full calibration for all sites ~ 1X per week for each weather variable Using lookup tables ~ every hour (8 hrs, was 1hr) “bias” obs Forecast PDF Probability Probability Forecast PDF obs “spread” or “dispersion” calibration Temperature [K] Temperature [K] National Security Applications Program Research Applications Laboratory ATEC-4DWX IPR, Aug 11-12 2009

  7. 3-hr dewpoint time series Station DPG S01 Before Calibration After Calibration National Security Applications Program Research Applications Laboratory ATEC-4DWX IPR, Aug 11-12 2009

  8. 42-hr dewpoint time series Station DPG S01 Before Calibration After Calibration National Security Applications Program Research Applications Laboratory ATEC-4DWX IPR, Aug 11-12 2009

  9. PDFs: raw vs. calibrated Blue is “raw” ensemble Black is calibrated ensemble Red is the observed value Notice: significant change in both “bias” and dispersion of final PDF (also notice PDF asymmetries) obs ATEC-4DWX IPR, Aug 11-12 2009

  10. Troubled rank histograms Counts 0 10 20 30 Counts 0 10 20 30 1 2 3 4 5 6 7 8 9 10 Ensemble # 1 2 3 4 5 6 7 8 9 10 Ensemble # ATEC-4DWX IPR, Aug 11-12 2009

  11. 3-hr dewpoint rank histograms Station DPG S01 National Security Applications Program Research Applications Laboratory ATEC-4DWX IPR, Aug 11-12 2009

  12. 42-hr dewpoint rank histograms Station DPG S01 National Security Applications Program Research Applications Laboratory ATEC-4DWX IPR, Aug 11-12 2009

  13. RMSE of ensemble members Station DPG S01 42hr Lead-time 3hr Lead-time National Security Applications Program Research Applications Laboratory ATEC-4DWX IPR, Aug 11-12 2009

  14. Significant calibration regressors Station DPG S01 42hr Lead-time 3hr Lead-time National Security Applications Program Research Applications Laboratory ATEC-4DWX IPR, Aug 11-12 2009

  15. Future plans • Refine lookup table process to decrease computation time (required as calibration data size continues to increase and new weather variables are added) • Implement for a) wind speed, b) wind direction, c) precipitation,d) surface pressure • Diagnose most informative model set to use operationally • Develop scheme for model points without surface observations over whole model domain National Security Applications Program Research Applications Laboratory ATEC-4DWX IPR, Aug 11-12 2009

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