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Yong-Run Guo Mei-Hsin Chen Ya-Ting Tsai

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Yong-Run Guo Mei-Hsin Chen Ya-Ting Tsai

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  1. Mid-Term review of 2008 CWB projectP.I.:Y-H. Kuo1,2Y.-R. Guo1 (WRF-Var lead)H. Liu3 (WRF-EnKF lead)J. Braun2 (Ground-based GPS lead)Fei Chen4 and Mike Barlage4(HRLDAS)CWB Visitor: Mei-Hsin Chen, Ya-ting Tsai, and Yun-Tien Lin1NCAR/MMM, 2UCAR/COSMIC, 3iMage, and 4RAL9 September 2008

  2. Task 1: Support for the WRFVar component of the CWB operational system and preparation for the upgrade of WRFVar 3.0

  3. Task 1: Support for the WRFVar component of the CWB operational system and preparation for the upgrade of WRFVar 3.0 Yong-Run Guo Mei-Hsin Chen Ya-Ting Tsai

  4. Task#.1.1 Support for the WRFVar component of CWB operational system • I received about 50 e-mails from CWB (most from Eric Chiang) since 1 Jan. 2008 To debug the WRFVar system and answered the questions a, 20080818Z case: Psfc = NaNQ? WPS/WRF problem (Jim Bresch answered) b, SATEM data assimilation: fixed the bugs c, update_bc program: low boundary update d, obsproc for GPS PW and observation error definition (obserr.txt) e, sfc_assi_options=2 problem: formulation, reference, and results… f, Psfc incremnets = 0 problem g, Typhoon re-location problem: 2007100600Z Krosa case h, pseudo ob bogus in CWB WRFvar 2.1 code I, -O3 and –O2 compiler options in CWB and NCAR.

  5. Task#.1.2 Preparation for running WRFVar 3.0 in CWB • 1.2.1 Install and compile the WRFVar 3.0 code on CWB IBM • On 04/23/08, Eric Chiang installed WRFVar 3.0 on CWB IBM • On 04/30/08, Eric completed the tutorial test case run in CWB IBM • 1.2.2 Test the WRFVar 3.0 with the exactly same configuration used in WRFVar 2.1 Eric completed WRFVar 3.0 run with 64 CPUs for CWB case. Guo passed the script and namelist.input to Eric on 07/26/2008 for running WRFVar 3.0 • 1.2.3 Test the accessory functions of WRFVar 3.0 (partially done) Guo posted the WRFVar 3.0/gen_be wrapper on the NCAR/CWB/ web page on 08/25/2008 • 1.2.4 Complete the restropective 3-hour cycling run tests with WRFVar 3.0 3-hour WRFVar 2.1 cycling run completed. 3-hour WRFVar 3.0 cycling run (Eric Chiang, CWB) ** v2.1 and v3.0 could not be identical because WPS/WRF-real.exe (v3.0) were changed. We only want to have similar results.

  6. a) Seven Exps completed for one month (200708) cycling run: • Objectives: • To find better CV5 BE • To demonstrate GPSRO impacts • To find the better length of cycle. • Single obs tests with 200708 BES and Background error statistic tuning based on Hollingworth&Lennberg method for Domain 1 (45km) CV5

  7. Verification against SOUND • Exp3 ans 3n showed that new (Aug) CV5 BE is better than the old (Jun) CV5 BE. • Exp3n and 4 showed that 3-h cycle is better than 6-h cycle. • Exp4 and 5 showed that CV5 BE is little better than or comparable to CV3 BE. • Exp4 and 6 showed that assi. Of GPSRO improved T and Q. • Exp4 and 7 showed that 1-h cycle has no positive impact.

  8. Verification against SYNOP • Exp3 and 3n showed that the new (Agu) CV5 BE improved U, V, and P over the old (Jun) CV5 BE. • Exp3n and 4 showed that 3-h cycle is better than 6-h cycle. • Exp4 and 5 showed that CV5 BE is comparable to CV3 BE. • Exp4 and 6 showed that assi. with GPSRO is better than that without GPSRO. • Exp4 and 7 showed that 1-h cycle is better than 3-h cycle.

  9. Comparison between Exp. 4 (CV5) and 5 (CV3): 36-h forecasts of U and P 2007081612Z Typhoon SEPAT (1300Z to 1906Z) Landfall in east coast of Taiwan at about 1722Z.

  10. In order to improve the Typhoon forecast • Multiple Outer-Loops with Tuned Background Error Statistics (MOLTBES) technique (see • http://box.mmm.ucar.edu/individual/guo/individual_guo/CWB/CWB_Project_2008.html • under section Data assimilation) • Four experiments conducted: • GFS : using NCEP GFS at 2007081300Z as FG, then 6-h cycling until 2007081800Z. • CYC : using 6-h forecast from 2007081218Z as FG, the 6-h cycling until 2007081800Z. • GFSEXT : same as GFS but using MOLTBES. • CYCEXT : same as CYC but using MOLTBES.

  11. Averaged errors (km) of the track forecast for 11 initial times With the MOLTBES technique, the averaged track forecast errors over 72-h period are reduced about 50%.

  12. Averaged errors of track forecast over 6 to 24-h With the MOLTBES technique, the averaged track forecast errors over the first 24-h period are reduced about 65%.

  13. Averaged errors of track forecast over 30 to 48-h With the MOLTBES technique, the averaged track forecast errors over the second 24-h period are reduced about 50%.

  14. Averaged errors of track forecast over 54 t0 72-h forecast With the MOLTBES technique, the averaged track forecast errors over the third 24-h period are reduced about 35%.

  15. Track forecast and track errors at initial times: 0000 UTC 15 and 16 July 2007 2007081600Z 2007081500Z

  16. MOLTBES technique is very effective to reduce the track forecast errors for Typhoon SEPAT. For 2005 Typhoon Haitang and 2006 Typhoon Shanshan, the similar results were obtained. This technique is much effective for cycling runs. Note: The MOLTBES now is only working with WRFVar_2.1 serial mode run. So in IBM, 3 outer-loops WRFVar run need about 50 minutes wall-clock time. More software engineering work are needed to make MOLTBES for WRFVar_2.1 and WRFVar_3.0

  17. Task#.1.3 Develop the capability of the ground-based GPS ZTD data assimilation • 1.3.1 Development and implementation of forward, tangent linear, and adjoint code for ZTD the code developments for GPS ZTD decoder, obsproc, and WRFVar were completed on 06/02/2008 the wrfvar_2.1 code and testing data (2005 Typhoon Haitang) are posted on the NCAR/CWB web page on 07/25/2008. • Testing the capability of assimilating CWB GPS ZTD data 4 Experiments were conducted by Yating Tsai for Typhoon Kalmaegi (2008071600Z, CV5, 3-h cycling): NOGPS, GPSPW, GPSZTD, and GPSZTD10 • Comparing the results with GPS PW data assimilation Typhoon forecast: Rainfall forecast: • Preparation of a report tom summarized the results

  18. Experiment design • NOGPS (Conventional obs only) • GPSPW (Conventional + GPSPW) • GPSZTD (ZTD obs error from GPS data) • GPSZTD10 (ZTD obs error is a constant = 10 mm) Kalmaegi landfall 1600Z 1612Z 1700Z 1712Z 3-h cycling started from 2008071600Z

  19. Averaged errors of track forecast over 60-h period for Typhoon Kalmaegi Assimilation of GPS ZTD got 29% reduction of the track forecast error in compared with that without GPS data assimilation.

  20. Kalmaegi track forecast from initial times: 2008071600Z and 2008071700Z 1700Z 1600Z

  21. Topics for Discussions • Date of project final review (2 Dec. 2008) • Deliverables check-off • Contract payments (not yet been paid) • Tasks to be performed for the remainder of 2008 both at NCAR and CWB • WRFVar/WRF 3.0 end-to-end testing at CWB (Eric Chiang): 3-h cycling with bintype=1 CV5 BE • GPS ZTD experiments and report: Rainfall forecast verification.

  22. Tasks for 2009 • WRFVar 2.1/3.0 support • Further tuning of the CV5 BES • Multiple outer-loops (mpi code) • Ground-based GPS ZTD operational implementation (retrospective experiments) • Non-local GPSRO assimilation in WRFVar 3.0 • Slant-path wet delay code development and experiments (OSSE and real data?) • Radar data assimilation experiments with 4DVar

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