1. Naomi Surgi NCEP/Environmental Modeling Center WHERE AMERICA’S CLIMATE AND WEATHER SERVICES BEGIN Hurricane Program Leader

2. Overview HWRF implementation strategy HWRF development Results: HWRF vs. GFDL HWRF for the future

3. 02-03 03-04 05 06 07 Mesoscale Data Assimilation for Hurricane Core Prelim. Testing grid, hurricane physics HWRF Final GFDL upgrades TRANSITIONING TO HURRICANE WRF Begin R&D Continue upgrades T&E Begin Physics upgrades IOC IOC GFDL

4. Pre-Implementation Strategy for HWRF FOR THE HWRF OPERATIONAL IMPLEMENTATION: HWRF MUST PERFORM AT LEAST AS WELL AS THE GFDL MODEL UPGRADE GFDL SYSTEM / Establish GFDL as benchmark - UPGRADE GFDL PHYSICS WITH GFS PHYSICS (’04) (GFS SAS and PBL schemes) - INCREASE RESOLUTION (’05) (inner nest from 18 to 9km.) - IMPLEMENT EMC Ferrier MICROPHYSICS to GFDL - Upgrade AIR-SEA PHYSICS (reduced drag) ‘06 - IMPROVE OCEAN INITIALIZATION TRANSITION GFDL UPGRADES TO HWRF

5. HWRF Development  CONDUCTED 25+ EXPERIMENTS, e.g. 25 versions of the HWRF  Tested each upgrade (numerics, physics, coupling) for clean comparisons - comprehensive testing >200 cases  Next 2-3 weeks: FINALIZE HWRF (ocean coupling for hi- res nest, vortex initialization, cumulus momentum mixing)  PERFORM EXTENSIVE COMPARISONS BETWEEN GFDL AND HWRF FOR MULTIPLE SEASONS AND STORMS (‘04, ’05, ’06)

6. Other upgrades for ‘07 GFDL T&E already underway for new global system: GFS (Hybrid) – 382/64L; SIGMA/P (in trop) New Data Assimilation System, e.g. GRID POINT STATISTICAL INTERPOLATION (GSI)

7. THE HURRICANE WRF (HWRF) PREDICTION SYSTEM H WRF began development 2002 Operational this season; GFDL will run in parallel Non-hydrostatic hurricane model; movable, inner nest Coupled air-sea-land prediction system Advanced data assimilation for hurricane core (make use of airborne doppler radar obs and land based radar)

8. HWRF continued….. Assimilation of ocean observations Advanced physics for high resolution and air-sea Coupling with wave model Land surface coupled to hydrology/inundation Coupling with dynamic storm surge

9. Hurricane-Wave-Ocean-Surge-Inundation Coupled Models High resolution Coastal, Bay & Estuarine hydrodynamic model Atmosphere/oceanic Boundary Layer HYCOM 3D ocean circulation model WAVEWATCH III Spectral wave model NOAH LSM NOS land and coastal waters NCEP/ Environmental Modeling Center Atmosphere- Ocean-Wave-Land runoff fluxes wave fluxes wave spectra winds air temp. SST currents elevations currents 3D salinities temperatures other fluxes surge inundation radiative fluxes HWRF SYSTEM NMM hurricane atmosphere

10. THE Coupled HWRF SYSTEM 2007: Initial Operating Capability Movable, 2- way nested grid (9km; 27km/42L; ~75X75) Advanced Physics (atmosphere-waves-ocean) Coupled to Ocean (POM) Advanced vortex initialization (3-D var) – parallel run w/radar data Multi-grid wave model - (static multi-grids, some shallow water physics) Multi-grid wave model - (static multi-grids, some shallow water physics)

11. Wave model development  ’07 - operational implementation of multi- grid wave model with static grids and initial surf-zone physics.  ‘08 - development of re-locatable grids.  ‘08+ - incorporation in HWRF with relocatable grids, advanced stress computation and expanded shallow water physics.

12. The multi-grid wave model Deep ocean model resolution dictated by GFS model Higher coastal model resolution dictated by model economy Highest model resolution in areas of special interest Hurricane nests moving with storm(s) like GFDL and HWRF This is the 2003 vision; In 2007 areas will mimic areas of NWS forecast responsibility

13. Wave model resolution in minutes for operational implementation in FY2007-Q4, mirroring WFO NDFD responsibilities.

14. HWRF Results– 4X daily throughout ’04, ’05, ‘06 hurricane season for all storms – system very stable and reliable Over two hundred cases with prelimary HWRF system Results from a subset of these

15. HWRF (coupled- parent domain) TRACK

16. Intensity

17. HWRFDENNIS

18. HURRICANE EMILY

19. HWRF Hurricane Katrina

20. HWRF Hurricane Wilma

21. Forecast Spread: Katrina 2005 HWRF GFDL

22. Forecast Spread: Wilma 2005 HWRF GFDL

23. Forecast Spread: Ernesto 2006 HWRF GFDL

24. WHAT’s NEXT ????

25. THE Coupled HWRF SYSTEM  Couple to HYCOM, WAVEWATCH III (’08)  Improve data assimilation of airborne and land based radars for hurricane core initialization (continuing)  Advance Physics – sea spray (’08-’09) (collaboration with ESRL, URI), improved stress, cloud/radiation  Waves up to the coastline (Non-linear interactions, surf- zone shallow-water physics) (collaboration w/USA, HRD)   Land surface coupling to streamflow and inundation (collaboration w/USA, HRD)   Development of HWRF ensembles   Coupling to dynamic storm surge model (w/NOS) THE Coupled HWRF SYSTEM  Couple to HYCOM, WAVEWATCH III (’08)  Improve data assimilation of airborne and land based radars for hurricane core initialization (continuing)  Advance Physics – sea spray (’08-’09) (collaboration with ESRL, URI), improved stress, cloud/radiation  Waves up to the coastline (Non-linear interactions, surf- zone shallow-water physics) (collaboration w/USA, HRD)   Land surface coupling to streamflow and inundation (collaboration w/USA, HRD)   Development of HWRF ensembles   Coupling to dynamic storm surge model (w/NOS)

26. 08 09 10 11 12 Radial vel./ reflectivity Adv. DA SDBE Mesoscale Data Assimilation for Hurricane Core Advancing HURRICANE System Atm. Model physics and resolution upgrades (continuous) Atm/ocean boundary layer: wave drag, enthalpy fluxes (sea spray) Atm/ocean boundary layer: wave drag, enthalpy fluxes (sea spray) Microphysics, Radiation Microphysics, Radiation Incr. resolution (6km/>64L) (6km/>64L) Waves: surf-zone physics implement Waves: surf-zone physics implement Ocean: 4km. - continuous upgrades in RTOFS Ocean: 4km. - continuous upgrades in RTOFS ENSEMBLES??? Prototype Ens w/Navy Land coupling Implement Land coupling Implement Storm surge???

27.  Development of Advanced Probabilistic Guidance for Intensity/structure (in progress) HWRF Ensembles HWRF Ensembles Configuration Configuration initial conditions, resolution, members??? initial conditions, resolution, members??? OR OR Use of multi model ensembles (MME) Use of multi model ensembles (MME) (Explore shared MME w/Navy - Demo ’07, ’08…) (Explore shared MME w/Navy - Demo ’07, ’08…) (Value of very hi-resolution deterministic forecasts vs. ensembles?) (LES studies in progress - PSU)

28. Aircraft in Hurricanes Need to develop flight strategies for GIV and P-3’s for core missions Two mission profiles: Environment & Core Observations: GPS, Radar, AXBT’s Large increase in request for flight hours for core missions – HWRF requirement 4X/day for assimilation problem Working on operational requirement for AXBT’s

29. THANK YOU FOR YOUR ATTENTION… Many thanks: Gopal S, Qingfu, Bob T, Bill O, Vijay T, Young-Kwon, Isaac G., Morris B Scott Carter for $$$$$$$$ Scott Carter for $$$$$$$$

30. Extra slides

34. HWRFDENNIS

35. HYCOM T&E - Dennis

36. HURRICANE EMILY

37. HWRF Hurricane Katrina

38. HYCOM T&E Katrina

41. Wavewatch model at Landfall The eye positions are nearly identical, but the difference in spatial scales has a huge impact on the coastal wind fields. Driven by GFS winds Driven by GFDL/GFS winds

42. Two Weather Research and Forecasting (WRF) Model dynamical cores: (noted here to avoid further WRF confusion) ● NCEP Nonhydrostatic Mesoscale Model (NMM) Janjic, Gerrity and Nickovic, 2001, MWR Janjic, 2003, MAP Black, Tucillo, Parallelization, Optimization, WRF standards ● NCAR Explicit Mass Core (EMC or ARM) Klemp, Skamarock, Dudhia, 2000, Online Wicker and Skamarock, 2002, MWR Klemp, Skamarock, Fuhrer, 2003, MWR Michalakes, 2002

43. Single digit resolutions affordable for NWP ●Nonhydrostatic mesoscale NWP models needed. ●How do we build a true mesoscale NWP model? -Extend a cloud model to synoptic scales and beyond? -Build on NWP experience and extend NWP models to mesoscales? ●What should a successful nonhydrostatic mesoscale NWP model be able to do? -Reproduce classical nonhydrostatic solutions at high resolutions; -Competitive with mature NWP models at transitional resolutions.

44. Cloud models, conventional approach ( Klemp and Wilhelmson, 1978a,b, ) MM5, DWD LM, Nonhydrostatic Eta (Gallus and Rancic, 1996, QJ)… Pressure tendency Eq. Thermodynamic Eq. sigma-z (Gal-Chen, Somerville, MWR), z-sigma-z hybrid ( ● Often nonconservative, higher order, discretization ●NWP dealing with much larger range of spatial and temporal scales ●Specific difficulties: -How to introduce diabatic forcing? -3D divergence typically does not sum-up to zero, mass (etc.) conservation? -Rigid lid on top -Computational boundary condition on top in NWP applications Continuity Eq. Thermodynamic Eq. Gas Law Eq. Three Momentum Eqns Three Momentum Eqns

45. The NCEP NMM ● Instead of extending cloud models to larger spatial and temporal scales, NMM built on experiences of NWP (Janjic et al., 2001; Janjic, 2003), i.e., -Relaxing the hydrostatic approximation, while -Using modeling principles (Janjic, 1977, 1979, 1984) proven in NWP and regional climate applications. Nonhydrostatic equations split into two parts: -Hydrostatic part, except for higher order terms due to vertical acceleration, -The part that allows computation of the corrections in the first part, -Convenient for unified systems

46. Continued….. ● No linearizations or additional approximations required, fully compressible system ●The nonhydrostatic effects as an add–on nonhydrostatic module: -Easy comparison of hydrostatic and nonhydrostatic solutions; -Reduced computational effort at lower resolutions. ●Pressure based vertical coordinate. -Exact mass (etc.) conservation, -Nondivergent flow on coordinate surfaces (often forgotten), -No problems with weak stability, -Sigma-z system problems shifted to stratosphere and upper troposphere. ● “Competitive with mature hydrostatic NWP models …”

47. ☞ Nonhydrostatic model equations; for simplicity, inviscid, adiabatic, sigma: ● Φ, w and ε not independent, watch for overspecification! ●BC:at the top,at the bottom.

48. Coordinate system ● Rotated lat-lon lon lat Rotated lon Rotated lat ●More regular grid, longer time step This allows a transformation of the central coordinates at the equator to a specified location

49. NCEP Nonhydrostatic Mesoscale Model (NMM) Janjic, Gerrity and Nickovic, 2001, MWR Janjic, 2003, MAP Non-hydrostatic dynamics ●NMM Computationally robust, reliable in operations; many tests NWP, convective cloud runs, PBL LES, with resolutions from 50 km to 100 m; ●THREE TIMES faster than most established NH models ● NMM/HWRF Simplified Arakawa Shubert (Pan and Wu, 1994) GFS PBL/Surface physics (Troen, Mahrt, 1986; Hong and Pan, 1996) Radiation (Yu-Tai Hou, 2002; Mlawer (AER), 97) Microphysics (Ferrier et al., 2002) ●HWRF prototype ran during ’04, ’05, ‘06 hurricane season

50. Science Issues Fundamental questions (process/sensitivity studies):  Relative role of vortex vs. environment in influencing intensity.  Role of ocean. Role of Oceanic heat content.  Processes within atmosphere-ocean boundary layer on intensity/structure changes.  Determinants of structure and relationship with preexisting wave disturbance. Relationship between structure and intensity.

51.  Role of inner core processes for intensification/weakening, e.g. eyewall replacement cycles, mixing.  Relative role of physics, e.g. Air-sea, microphysics, convection etc. on intensity change in various environments (sheared vs. non-shear)

52. Some Model Related Issues  Data Assimilation   Assimilation of satellite radiances  Vortex Initialization definition of hurricane “core” circulation definition of hurricane “core” circulation where to take obs? difficult for mature storms; more elusive weaker circulations. (obs taken during RAINEX?) where to take obs? difficult for mature storms; more elusive weaker circulations. (obs taken during RAINEX?)  Physics  role of radiation? complexity of microphysics and interaction of microphysics with radiation  atmosphere/oceanic boundary layer for coupled air-sea-wave problem. Momentum (wave induced drag) and enthalpy fluxes (sea spray complexity?)

53.  Resolution -  relative importance of horizontal vs. vertical resolution for modeling intensity/structure (important consideration for ops)  Coupled Ocean -  advancements to support  initialization  vertical mixing  Obs to support effort data assimilation for improved ocean state (discussed at 2003 Air-Sea workshop at EMC)  Land Surface Coupling -  Complexity of coupling w/HWRF?  Sensitivity of LSM for track, structure/intensity, rainfall?  Future coupling with hydrology/inundation models.

54.  Validation/Verification/Diagnostics –  initialization  requirement for development of verification techniques  all stages of storm evolution; varying atmos/ocean environment  required obs to support model diagnoistics and verification, e.g IFEX effort led by HRD e.g IFEX effort led by HRD  particularly deficient in ocean obs.  temporal and spatial scales?

55.  Development of Advanced Probabilistic Guidance for Intensity/structure HWRF Ensembles HWRF Ensembles Configuration Configuration initial conditions, resolution, members??? initial conditions, resolution, members??? OR OR Use of multi model ensembles (MME) Use of multi model ensembles (MME) (Share w/Navy? COAMPS, GFDL (Share w/Navy? COAMPS, GFDL NCEP: HWRF, NAM) NCEP: HWRF, NAM) (Value of very hi-resolution deterministic forecasts vs. ensembles?)

56. HWRF TEAM Gopal S. ; Qingfu Liu; Bob T, Veejay T. ; Y. Kwon (soon)

57. HWRF atmosphere-ocean coupling Sea surface temperature to Atmosphere from: –Regional ocean (HYCOM) dx~ 8-14(km) –SST analyses (GFS) dx~ 30(km) Radiative/turbulence fluxes to Ocean from: –Atmosphere model (HWRF) dx~ 27(km) & 9(km) Boundary layer model uses surface wave information from: –Wave model (Wavewatch 3) dx~ 30(km)

58. Ocean initialization and assimilation Initial conditions from operational Atlantic forecast model (RTOFS): –Data is assimilated during the nowcast cycle of RTOFS Boundary conditions are derived from RTOFS: –Five day forecasts are sample for volume data twice daily and for the external velocity and surface elevations three hourly. Data Assimilation in RTOFS: –2D/3D Var –Data assimilated includes SST SSH CTD, XBT….

59. Wave model development at EMC  WAVEWATCH III - pre-operational and operational at NCEP for nearly a decade (hurricane wave models with GFS-GFDL winds since 2001)  Recent developments in wave modeling are largely driven by the hurricane (wave) forecast problem  Coupling of wind and wave models:  New parameterizations of wind stresses over waves in high wind regimes.  Development of a multi-grid wave model to mimic the grid layout of HWRF (use of high-res wind data, coupling)

60. Multi-grid wave model Virtually all present wave models consider one- way nesting only, with low resolution providing boundary data for high resolution models. Hurricanes require high resolution in generation area, but their swells are covering full basins. Hurricanes therefore require two-way nesting and relocatable nests. Coupling with hurricane models for the atmosphere benefit from identical grids. NCEP: Build upon the present operations: design as multiple grids in a single model.

61. Additional benefits of a multi-grid wave model Consolidation of global and regional models into a single model Maximum consistency between global and regional models Natural way of reducing resolution for ensembles by removing highest resolution coastal grids Additional benefits / applications for relocatable nests  On demand high resolution hazard models (plane crashes, oil spills etc.)  Navy: On demand high resolution coupled modeling

62. The multi-grid wave model Hurricane described with Rankin vortex with maximum wind 45 m/s at radius of 50km. Hurricane moves to the right at 5 m/s. Telescoping grids with 50, 15 and 5 km resolution. Circular outline of domains.

63. The multi-grid wave model Individual models with different resolution give inconsistent results. Running as a single model gives consistent results with variable resolution. Tolman and Alves, Ocean Modelling 2005.

64. THE HURRICANE WRF (HWRF) PREDICTION SYSTEM Will replace the GFDL in 2007 Coupled air-sea-land prediction system Advanced data assimilation for hurricane vortex Advanced physics for high resolution Coupling with wave model Land surface coupled to hydrology/inundation Coupling with dynamic storm surge

65. Development of Collaborations  HWRF WORKSHOP – JUNE 2002 (EMC) (45 attendees – estab. hurricane community) (45 attendees – estab. hurricane community)  1 st HWRF TUTORIAL – Oct. 2004 (EMC) (26 attendees – precocious hurr. modeling types) (26 attendees – precocious hurr. modeling types)  AIR-SEA WORKSHOP – MAY 2005 (EMC) (35 attendees – introduction of ocean community) (35 attendees – introduction of ocean community)  WRF/NMM Tutorial – Sept 2005 (JMT/Boulder) the beginning of “formal” training the beginning of “formal” training

66. Pre-Implementation Strategy for HWRF Upgrade GFDL as the benchmark for the HWRF UPGRADE GFDL PHYSICS WITH GFS PHYSICS (’04) (GFS SAS and PBL schemes) INCREASE GFDL RESOLUTION (’05) (inner nest from 18 to 9km.) IMPLEMENT EMC Ferrier MICROPHYSICS (in HWRF) ‘06 UPGRADE AIR-SEA PHYSICS (reduced drag) ‘06 IMPROVE OCEAN INITIALIZATION

67. TRANSITION GFDL UPGRADES TO HWRF Next 2-3 weeks:   FINALIZE HWRF (ocean coupling for hi-res nest, vortex initialization, cumulus momentum mixing)   PERFORM EXTENSIVE COMPARISONS BETWEEN GFDL AND HWRF FOR MULTIPLE SEASONS AND STORMS – ’04, 05, 06 – compare to GFDL results CONTINUED: PRE-IMP HWRF STRATEGY

68. Evolution of HWRF Development HWRFFirst moving nest NMM HWRF GFDL Initialization; 2005 Hurricane Season; Dennis H001HWRF Runs with GFS Initialization; 2005 Hurricane Season; Atlantic and East Pac, Near Real Time runs. H002HWRF Runs with New GFDL Surface Physics; Wilma, Rita and Emily H003HWRF Runs with GFDL Slab Model H004HWRF Runs with Two-Way Interactive Moving Nest (with feedbacks) H005/HWRF Runs with Varying physics time steps (1 min. and 5 min.) H006

69. Evolution of HWRF Development H007HWRF Runs with Varying Radiation Calls H008HWRF Runs using Initialization from Uncoupled GFDL; Dennis, Katrina, Rita and Wilma H009HWRF Runs with Varying Physics and Convection time steps H010/11HWRF Runs with QingFu's New Initialization Procedure (3DVAR) based on GFS analysis and GSI H012HWRF Runs with New Random Number Code for SAS Convection H013HWRF Runs with Upgraded Physics and Microphysics; Katrina, Philippe, Rita, Wilma and Beryl (2006)

70. Evolution of HWRF Development H014 HWRF Runs with QingFu's modified initialization that includes a bogus vortex specification H015/016HWRF Runs using QingFu's modified initialization package H017HWRF Runs with New Surface Physics (Bob Tuleya) and inclusion of Dissipative Heating H018/HWRF Runs with QingFu's modified initialization package (III) H019 H020HWRF Runs with Cloud Momentum Mixing Coefficient Introduced (kept at 0.5)

71. Evolution of HWRF Development H021HWRF Runs with QingFu's revised 3DVAR that uses 10 m winds (instead of level 1 winds) for initialization H022HWRF Runs using QingFu's modified initialization package (IV) that includes adjustment to Sea Level Pressure H023First Comprehensive Testing of the end-to-end HWRF Modeling System. Conducted 218 experiments that include Atlantic Hurricanes from 2004, 2005 and 2006 seasons. Results are presented at http://www.emc.ncep.noaa.gov/gc_wmb/vxt/ H024HWRF Runs with new Surface Enthalpy Flux Coefficient HCBS/HWRF Coupled Model Configuration, Initialization with High Resolution GFS Sigma & Hybrid Data – work in progress