Kazuhisa Tsuboki Hydrospheric Atmospheric Research Center (HyARC) Nagoya University

1. 11 November 2009 Kyoto University, Uji Campus, Kyoto International Symposium on Radar and Modeling Studies of the Atmosphere High-Resolution Simulation of Typhoons Using the Cloud-Resolving Model • Introduction • The cloud-resolving model: CReSS • Typhoons T0423 (1 km resolution) • Typhoons T0416 and T0418 (4 km resolution) • Typhoon T0613 (500 m) and tatsumaki (75m) Kazuhisa Tsuboki Hydrospheric Atmospheric Research Center (HyARC) Nagoya University

2. For prevention of disaster due to typhoon, accurate prediction and countermeasure are most important. • Rainfall intensity and wind speed should be predicted accurately and quantitatively. • For simulation of convective clouds and storms, we have been developing a cloud resolving model,“CReSS”(the Cloud Resolving Storm Simulator) since 1998. • The CReSS model is a non-hydrostatic and compressible equation model which optimized for parallel computers. • CReSS has been used for high-resolution simulation of high-impact weather systems such as typhoons, tornadoes, heavy rainfall and snowstorms. • In the CReSS version III, a new technique of domain setting was developed, which named “the tiling domain technique”.

3. Characteristics of the CReSS model • Basic equations: the non-hydrostatic and compressible equation system. • Coordinate system: a terrain-following in a two or three dimensional domain. • Spatial representation: finite difference method (Arakawa C grid in horizontal, Lorenz grid in vertical). • Time integration: mode-splitting scheme (acoustic terms implicit in vertical) • Ground model:n-layer 1-dim. thermal conductivity model. • Ocean model:n-layer 1-dim. diffusion model. • Surface process: bulk scheme (Louis scheme). • Map projections: Lambert, Polar stereo, Mercator, Lat-lon. • Parallel processing: inter-node: the Message Passing Interface (MPI) , intra-node: OpenMP. • The CReSS model is optimized for parallel computers (parallel and serial versions).

4. Typhoon simulation with Δx=1km :T0418

5. Typhoon simulation with Δx=1km :T0418

6. Snow storm over the Great Lakes in North America grid size: Δx=500m

7. Snow storm over the Great Lakes in North America grid size: Δx=500m

8. Heavy rainfall associated with Baiu front: Niigata heavy rain CReSS simulation Radar observation

9. Tatsumaki (tornado-scale vorticity) simulation with 75 m resolution.

10. A new technique to perform a parallel computation of the cloud-resolving model in an arbitrary-shaped region, which is named the “Tiling Domain Technique” for CReSS.

11. Typhoon T0423 (caused floods due to heavy rainfall.) T0423, 2004. 10. 20, 01UTC

12. Track of T0423 00Z, 21 Oct. 2004 4 days simulation 00Z, 17 Oct. 2004

13. Initial time JMA Best Track T0423

14. T = 36 hr JMA Best Track

15. T = 78 hr JMA Best Track

16. Total rainfall amount due to Typhoon 23 in 2004 simulated by 2km Exp. Maximum rainfall is 400～500mm

17. Experimental Design of Typhoon T0423 • Domain H: 1536 km × 1408 km × V: 18 km • H-gird size 　1000 m • V-grid size 　200 ~ 300 m (stretched) • Grid numbers　　 　H: 1539 × 1411× V: 63 • Integration time　　 30 hours • Time increment　 　large: 3 sec, small: 1 sec • Micro-physics 　the bulk cold rain type • Initial condition JMA Regional Spectral model output • Boundary JMA Regional Spectral model output • Surface 　　 　　 real topography and observed SST • ES node number　　128 nodes (1024 CPU)

18. Best track of T0423 (central pressure; hPa)

21. Total rainfall (mm) for 24hrs Nobeoka

22. Rainfall intensity (mm/hr) Bars:Observation Solid line: CReSS Dashed line: RSM Time (UTC)

23. Threat score of rainfall intensity (5mm/hr) Black line: CReSS Blue line: RSM Time (UTC)

24. Threat score of rainfall intensity (30 mm/hr) Black line: CReSS Blue line: RSM Time (UTC)

25. Total rainfall (mm) 1km Exp. Total rainfall amount by 2km Exp. Using Tiling Domain Technique

26. Typhoons T0416 and T0418 (caused severe disaster due to strong wind.) T0418, 2004. 9. 5, 01UTC

27. Experimental Designof T0418 Using TD Technique • Domain : W-E 53.1o (5120km), N-S 50.5o (4480km) • Horizontal grid number: 1283 x 1123 (all domain) • Number of tiles: 94 ( approx. 42 % of all domain) • Horizontal grid spacing: 4km • Vertical gird number: 67 • Vertical gird spacing: 160 ～350 m • Time difference: 8 sec • Integration period: 1.2 million seconds (14 days) • Topography and SST: real topo. and observed SST • Initial and boundary : JMA objective analysis (6hr) • Cloud microphysics: cold rain bulk parameterization • Radiation: considered for the ground temperature • Ocean model: 1-dim. diffusion model (50 layers, 20m) • Computation platform: the Earth Simulator (94nodes)

28. Rain and SLP at 3hrs from Initial. Track of T0416 Track of T0418 T0417 T0416

30. Time variation of the central sea-level pressure of T0418 JMA Global Aanlysis CReSS JMA Best Track Time (UTC) from 00UTC 25 August 2004

31. Comparison of Simulation with observation at 120hrs (5days) Typhoon 0416 is located at the southernmost part of Kyushu. CReSS Simulation Radar-AMeDAS Observation

32. Comparison of Simulation with observation at 312 hrs (13 days) Typhoon 0418 is located off the west coast of Kyushu. CReSS Simulation Radar-AMeDAS Observation

33. T0418

34. ーTatsumaki (tornado-scale vorticity) with Typhoon 0613, on September 17, 2006 in Nobeoka Cityー

35. Experimental Design of Typhoon T0613 • Domain H: 896 km × 896 km × V: 20 km • H-gird size 　500 m • V-grid size 　100 ~ 320 m (stretched) • Grid numbers　　 　H: 1795 × 1795× V: 67 • Integration time　　 6 hours • Time increment　 　large: 2 sec, small: 0.5 sec • Micro-physics 　the bulk cold rain type • Initial condition JMA Regional Spectral model (40km) • Boundary JMA Regional Spectral model (40km) • Surface 　　 　　 real topography and observed SST • ES node number　　128 nodes (1024 CPU)

37. 3 rainbands formed CReSS 500m Velocity and rain mixing ratio (shadings) at a height of 1.9km.

40. Supercell and tatsumaki in T0613 • Domain H: 60 km × 60 km × V: ～20 km • H-gird size 　75 m • V-grid size 　40 ~ 300 m (stretched) • Grid numbers　　 　H: 803 × 803× V: 67 • Integration time　　 6 hours • Time increment　 　large: 0.5 sec, small: 0.1 sec • Micro-physics 　the bulk cold rain type • Initial condition CReSS 500m simulation output • Boundary CReSS 500m simulation output • Surface 　　 　　 real topography and observed SST • Computer 　　HITACHI SR11000 (4nodes)

43. Vorticity (contour) and rain (color) central vorticity: 0.9/s 1000m

44. vorticity (contour) and pressure (color) pressure perturbation：27hPa 1000m

45. vorticity (contour) and speed (color) maximum speed: 70m/s 1000m

46. vorticity (contour) and vertical velocity (color) 1000m m/s

47. Summary For high-resolution simulations of high-impact weather systems, the CReSS model has been developed. “The tiling domain (TD) technique” was developed to perform a simulation in an arbitrary-shaped domain. The arbitrary-shaped domain is composed of many small rectangular domains named “domain tiles”. Each domain tile is, further, divided into sub-domains if necessary. Parallel processing is performed between sub-domains as well as between domain tiles. Using the TD technique, we performed a simulation experiment of the typhoons 0423 (2km, 4days) and 0418 (2km, 14 days). Both typhoons are successfully simulated: typhoon tracks, deepening central pressure with time, rainfall distribution and rainfall amount. The rainbands of typhoon 0613 was simulated with 500 m resolution and tatsumaki(tornado-scale vortex) with 75 m.

48. Thank you !! The CReSS model is free for scientific researches. If you are interested in CReSS, Please contact with me (K. Tsuboki). (HyARC, Nagoya University)

49. Rainbands of T0613 JMA radar 14JST, 17 Sept. Nobeoka

50. Domain Decomposition Tiling Domain Technique grid points of inner domain grid points at boundary partition lines of sub-domains partition lines of tiles Number of tiles: 3 Number of sub-domains in each tile: 4 Total number of sub-domains: 12