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Proposed RUC Change - September 2004

Stan Benjamin – NOAA/FSL Geoff Manikin – NOAA/NCEP/EMC. Proposed RUC Change - September 2004. Modifications to RUC analysis Improved surface / CAPE analyses and forecasts. History 1) RUC change package implemented on 14 April 2004

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Proposed RUC Change - September 2004

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  1. Stan Benjamin – NOAA/FSL Geoff Manikin – NOAA/NCEP/EMC Proposed RUC Change - September 2004 • Modifications to RUC analysis • Improved surface / CAPE analyses • and forecasts

  2. History • 1) RUC change package implemented on 14 April 2004 • Included model, land-use, and analysis changes. Analysis change was mainly to use boundary-layer depth to better assimilate surface observations, goal: improve CAPE and boundary-layer analysis. • 26 April 2004 – analysis change recalled (other changes retained). Problem – Noise in moisture fields, made worse by PBL-based assimilation. Recall advised by EMC and FSL. • May-June - FSL/EMC investigation / redesign. • Late June – Sept. EMC/NCO parallel testing of RUC with redesigned moisture analysis, including PBL-based assimilation.

  3. Original slides from April 2004 Problems with model PBL structure in RUC analysis Sounding structure is sometimes not realistic and does not account for boundary-layer depth No accounting in current RUC analysis for vertical correlation of forecast error near surface based on estimated boundary-layer depth

  4. Original slides from April 2004 PBL-based METAR assimilation Problem: Representativeness of sfc data in PBL not used Design: Use METAR data through PBL depth from 1h fcst Create extra pseudo-residuals (obs-bkg) in PBL RUC oper analysis 18z 3 Apr 02 IAD

  5. Summary of proposed RUC analysis changes – September 2004 Use of boundary-layer depth in METAR assimilation - redesigned version Constrained moisture analysis increments Constrained moisture and temperature near-surface observation residuals

  6. CAPE - 2100z 20 April 2004 RUC analysis Operational RUC Rerun of RUC (from 00z onward) with modified RUC analysis Problem areas gone. Improved CAPE in IL/IA area (tornado outbreak) Problem areas

  7. PBL-based METAR assimilation Use METAR data through PBL depth from 1h fcst RUC oper analysis 18z 3 Apr 02 IAD Effect of PBL-based METAR assimilation x x x x

  8. Oper RUC (OI analysis) Effect of PBL-based assimilation RUC 6h CAPE fcsts Valid 2100z 10 Nov 2002 Problem with all models in this case: Insufficient CAPE RUC w/ 3DVAR + PBL obs

  9. FSL rerun - 3DVAR Oper - OI • RUC • 6h fcsts • CAPE • Valid • 2100z • 10 Nov 03 • FSL rerun • 3DVAR • + PBL obs

  10. Parallel testing for RUC analysis change Real-time (warm season) 19 August – current time Retrospective (cold season) 1-20 February 2004

  11. Cold-season testing – 1-20 Feb 2004 - Upper-air wind 00h 03h RUC oper – solid RUCX - dashed 12h

  12. Cold-season testing – 1-20 Feb 2004 - Upper-air temp 00h 03h RUC oper – solid RUCX - dashed 12h

  13. Warm-season testing – 19 Aug-20 Sep 04 - Upper-air wind 00h 03h RUC oper – solid RUCX - dashed 12h

  14. Warm-season testing – 19 Aug-20 Sep 04 - Upper-air temp 03h 00h RUC oper – solid RUCX - dashed 12h

  15. Warm-season testing – 19 Aug-20 Sep 04 – 2-mtemp RUC oper – pink RUCX - blue 03h Valid at 00z 00h 3h 12h Valid at 12z

  16. Cold-season testing – 1-20 Feb 04 – 2-mtemp RUC oper – pink RUCX - blue Valid at 00z 3h 12h Valid at 12z

  17. RUC2 – oper RUC20 RUCX – para - revised moisture anx incl. PBL-based assimilation Case – 00z 21 July 2004 para oper Rome, OR para oper Winnemucca, NV

  18. RUC2 – oper RUC20 RUCX – revised moisture anx incl. PBL-based assimilation Case – 12z 1 July 2004

  19. RUC2 – oper RUC20 RUCX – parallel - revised moisture anx incl. PBL-based assimilation Case – 00z 13 July 2004 - 2m temp

  20. RUC2 – oper RUC20 RUCX – parallel -- revised moisture anx incl. PBL-based assimilation Case – 00z 13 July 2004 - 2m dewpoint

  21. Summary of proposed RUC analysis changes – September 2004 Use of boundary-layer depth in METAR assimilation - redesigned version - Constrained moisture analysis increments - Constrained moisture and temperature near-surface observation residuals Upper-air verification – slightly better than oper Surface verification – similar to oper Case studies – better CAPE, sfc temp/dewpoint analyses --------------------------------------------------------------- Interim fix for RUC moisture analysis for now. Planned change of moisture variable from ln-q to RH with 13km RUC package.

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