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TC relocation scheme of CWB WRF

TC relocation scheme of CWB WRF. I nitiated by Chi-Sann Liou(NRL), Der-Song Chen, Ling-Feng Hsiao Modified by Ling-Feng Hsiao, Yong-Run Guo(NCAR), Chuen-Teyr Terng Tested by Kang-Ning Huang, Ling-Feng Hsiao Thanks for Jing-San Hong, Chuen-Teyr Terng.

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TC relocation scheme of CWB WRF

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  1. TC relocation scheme of CWB WRF Initiated by Chi-Sann Liou(NRL), Der-Song Chen, Ling-Feng Hsiao Modified byLing-Feng Hsiao, Yong-Run Guo(NCAR), Chuen-Teyr Terng Tested by Kang-Ning Huang, Ling-Feng Hsiao Thanks for Jing-San Hong, Chuen-Teyr Terng

  2. Relocation Scheme (on eta-surface, maximum to 4 tropical cyclones): • apply filter scheme to get basic flows(filter out L< 1200km) Ub • (2) Compute perturbation fieldsas the residual of the basic flow from total fields • Up = U – Ub • (3) Interpolate sigma=.85 perturbation wind to TC centered polar coordinates and compute azimuthally averaged tangential wind speed at 24 directions Up(24) • (4) Determine the TC-edge locations, • From the starting location, search outward at 24 directions to find the first place that • a. v < 6 m/s and dv/dr < 4x10-6, or b. v < 3 m/s until 800km end • (5) compute non-TC perturbation fieldsby the 2-pass Barnes analysis Up_ntc • (6) compute TC circulationas the residual of non-TC perturbation from the total perturbation fields Up_tc = Up – Up_ntc

  3. Skip the relocation scheme when: • The distance between (obs – firstguess) < 1 grid • The Max. wind of < 15m/s • The center is too close to domain LB < 300km • The center is too close to land ( >10m) < 200km ( for eta-coord.)

  4. How to get MU & PHLing-Feng Hsiao, Yong-Run Guo Relocation (U, V, T, QVAPOR, PSFC) PSFC increment increment of PSFC and QVAPOR, base of MU and QVAPOR MU increment pressure, density, temperature, MU, QVAPOR PH

  5. basic flow Total field non-TC perturbation field TC circulation Relocated TC circulation

  6. basic flows Total field non-TC perturbation fields TC circulation Relocated TC circulation

  7. Total field basic flow non-TC perturbation field Relocated TC circulation TC circulation

  8. TYPHOON JANGMI (PSFC) Terrain Pressure Before (Black) VS After (Red) Relocation relocated the TC circulation only

  9. TYPHOON JANGMI (MU) relocated the TC circulation only

  10. Before relocation after relocation obs relocated the TC circulation only

  11. TYPHOON JANGMI (PH) PH (perturbation geopotential) at eta=.85 Before (Black) VS After (Red) Relocation relocated the TC circulation only

  12. TYPHOON JANGMI (PH) PH (perturbation geopotential) at eta=.49 Before (Black) VS After (Red) Relocation relocated the TC circulation only

  13. without relocation with relocation

  14. without relocation with relocation

  15. without relocation with relocation

  16. without relocation with relocation

  17. with relocation without relocation

  18. without relocation with relocation

  19. TC Bogus bogusing of the synthetic observationsdeveloped by Jen-Ho Chen Fields: 1. Winds: Ranking vortex + latest 6 hr movement of the cyclone 2. Mass: Gradient wind balance Distributions: 1. about 40 synthetic observations (depends on the size of TC) 2. every 0.5 degrees from the center (36 directions, TC edge ≈ 6m/s, asymmetry) 3 . 21 standard pressure levels in vertical (1000 to 150 hPa)

  20. without relocation with relocation

  21. without relocation with relocation

  22. without relocation with relocation

  23. without relocation with relocation

  24. without relocation new bogus with relocation new bogus 12 24 36 48 60 72 hours With 90 167 203 222 230 276 km Without 207 241 305 357 446 573 km Cases 16 16 16 16 16 14

  25. Modified by Hong J.-S.

  26. with relocation new bogus old topo. with relocation new bogus new topo. 12 24 36 48 60 72 hours Old 90 167 203 222 230 276 km New 85 114 142 187 251 385 km Cases 16 16 16 16 16 14

  27. with relocation op bogus zig-zag with relocation new bogus with relocation op bogus zig-zag with relocation new bogus

  28. with relocation op bogus zig-zag with relocation new bogus with relocation op bogus with relocation new bogus

  29. with relocation new bogus with relocation op bogus 12 24 36 48 60 72 hours New 90 167 203 222 230 276 km Op 110 151 229 308 412 497 km Cases 16 16 16 16 16 14

  30. Compare typhoon intensity with different bogus

  31. Huge forecast error after 08092712 with relocation new bogus new topo. GD with relocation new bogus new topo. KF 12 24 36 48 60 72 hours KF 90 160 208 229 338 373 km GD 85 114 142 187 251 385 km Cases 16 16 16 16 16 14

  32. Compare typhoon intensity with different cumulus scheme GD 12 24 36 48 60 72 hours GD 88 167 263 340 465 778 km KF 83 177 317 408 678 1235 km KF

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