Naomi%20Surgi

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Advanced Hurricane Modeling at EMC The HWRF

Naomi Surgi
HWRF Program Leader
NCEP/Environmental Modeling Center
WHERE AMERICAS CLIMATE AND WEATHER SERVICES
BEGIN
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Overview

• HWRF 07 implementation strategy
• HWRF development
• Results HWRF vs. GFDL
• HWRF for the future

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TRANSITIONING TO HURRICANE WRF
02-03 03-04 05
06 07
Mesoscale Data Assimilation for Hurricane
Core
GFDL
Final GFDL upgrades
Continue upgrades
Begin Physics upgrades

HWRF
Prelim. Testing grid, hurricane physics
IOC
Begin RD
TE
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• THE HURRICANE WRF (HWRF)
• PREDICTION SYSTEM
• Community based infrastructure (HWRF began
  development 2002)
• Non-hydrostatic hurricane model movable,
  nested grid
• Slated to become operational in 2007 GFDL will
  run in parallel
• Coupled air-sea-land prediction system
• Advanced data assimilation for hurricane core
  (make use of airborne doppler radar obs and land
  based radar)

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• HWRF continued..
• Assimilation of ocean observations
• Advanced physics for high resolution and
  air-sea
• Coupling with wave model (08)
• Land surface coupled to hydrology/inundation
  (09)
• Coupling with dynamic storm surge (gt2010)

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Hurricane-Wave-Ocean-Surge-Inundation Coupled
Models
NCEP/Environmental Modeling Center Atmosphere-
Ocean-Wave-Land
NOS land and coastal waters
HWRF SYSTEM

NMM hurricane atmosphere
NOAH LSM
runoff
High resolution Coastal, Bay Estuarine
hydrodynamic model
surge inundation
fluxes
Atmosphere/oceanic Boundary Layer
radiative fluxes
winds air temp.
other fluxes
elevations currents 3D salinities
temperatures
SST currents
HYCOM 3D ocean circulation model
wave spectra
WAVEWATCH III Spectral wave model
wave fluxes
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• 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
• TRANSITION GFDL UPGRADES TO HWRF
• PERFORM EXTENSIVE COMPARISONS BETWEEN GFDL AND
  HWRF FOR MULTIPLE SEASONS AND STORMS

Joint EMC/TPC TE document now available
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• 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
• UPGRADE AIR-SEA PHYSICS (reduced drag)
  06
• IMPROVE OCEAN INITIALIZATION

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CONTINUED PRE-IMP HWRF STRATEGY

• TRANSITION GFDL UPGRADES TO HWRF
• Next 3-4 weeks
• HWRF OCEAN COUPLING (ready in 2-3 weeks)
• FINALIZE HWRF PHYSICS (wave dependent drag,
  cumulus momentum mixing)
• THEN..(begin in January)
• PERFORM EXTENSIVE COMPARISONS BETWEEN GFDL AND
  HWRF FOR THREE SEASONS over ATL and EPAC

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• THE Coupled HWRF SYSTEM
• 2007
• Movable, 2- way nested grid (9km 27km/42L
  75X75)
• Coupled with ocean (AXBT, altimeter data )
• Advanced Physics (atmosphere-waves-ocean)
• Advanced vortex initialization (3-D var
  w/airborne radar obs to run in parallel)

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HWRF Results 4X daily throughout 04, 05, 06
hurricane seasons for all storms system very
stable and reliable Twenty three HWRF
experiments to test and verify each part of
system for clean comparisons HYCOM
testing/validation
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HWRF DENNIS
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HYCOM TE - Dennis
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HURRICANE EMILY
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HWRF Hurricane Katrina
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HWRF Hurricane Wilma
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Comparisons HWRF vs. GFDL (2006 Version)
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HWRF Better than GFDL (1-5 days)
HWRF Better than GFDL (1-3 days)
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HWRF Comparable than GFDL (1-3 days)
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HWRF Comparable or Better than GFDL (Beyond
72-hrs)
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HWRF Worse than GFDL
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HWRF Better than GFDL
HWRF Comparable to GFDL
except
HWRF Worse than GFDL
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Forecast Spread Katrina 2005
GFDL
HWRF
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Forecast Spread Wilma 2005
HWRF
GFDL
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Forecast Spread Ernesto 2006
GFDL
HWRF
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Forecast Spread Dennis 2005
HWRF
GFDL
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Forecast Spread Rita 2005
HWRF
GFDL
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HWRF better than GFDL
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HWRF better than GFDL
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PAUL (17E) 2006
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ROSA (19E) 2006
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Mean Track Errors for East Pac, 2006 (74 cases)
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Mean Track Errors for all 11 storms (218 cases)
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• Next 3-4 weeks
• HWRF OCEAN COUPLING (ready in 2-3 weeks)
• FINALIZE HWRF PHYSICS (wave drag, cumulus
  momentum mixing)
• THEN..(begin in January)
• PERFORM EXTENSIVE COMPARISONS BETWEEN GFDL AND
  HWRF FOR MULTIPLE SEASONS AND STORMS

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Aircraft in Hurricanes
Need to develop flight strategies for GIV and
P-3s Need to obtain resources for flight
hrs/addl crews New operational requirement for
AXBTs Two mission profiles Environment
core Observations GPS, AXBTs,
Radar Requirement for operational status of
P-3s
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WHATs NEXT ????
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• THE Coupled HWRF SYSTEM
• 2007
• Movable, 2- way nested grid (9km 27km/42L
  75X75)
• Coupled with ocean (w/data assimilation for
  AXBTs, altimeter data )
• Advanced Physics (atmosphere-waves-ocean)
• Advanced vortex initialization (3-D var
  w/airborne radar)
• 2008 - 2012
• Coupling to Wavewatch III
• Land surface coupling to streamflow and
  inundation
• Development of HWRF ensembles
• Coupling to dynamic storm surge model (w/NOS)

• Wave Coupling
• 07 Multi-grid wave model (static)
• 08 Movable multi-grid
• 09 Waves up to the coastline
  (Non-linear interactions, surf-zone shallow-water
  physics)

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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
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Advancing HURRICANE WRF System
08 09 10
11 12
Mesoscale Data Assimilation for Hurricane Core
Radial vel. Advance reflectivity
A4DDA

Atm. Model physics and resolution upgrades
(continuous)
Atm/ocean boundary layer wave drag,
enthalpy fluxes (sea spray)
Microphysics, radiation



Incr. resolution (4km/gt64L?)

Waves surf-zone physics implement
Ocean 4km. - continuous upgrades in
ODAS

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• Development of Advanced Probabilistic Guidance
  for Intensity/structure (in progress)
•  HWRF Ensembles
• Configuration
• initial conditions, resolution,
  members???
• OR
•   Use of multi model ensembles (MME)
• (Share w/Navy?)
• (Value of very hi-resolution deterministic
  forecasts vs. ensembles?) (LES studies in
  progress)

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HWRF and the community

• Current release HWRF w/movable, nested grid
  (2-way)
• Updated physics
• Future version coupled HWRF system

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The Way forward
Joint strategy/document between NOAA, NRL, NASA.
Available January through OFCM
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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.

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• 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)
  

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• Some Model Related Issues
• Data Assimilation
• Assimilation of satellite radiances
  
• Vortex Initialization
• definition of hurricane core
  circulation
• 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?)

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• 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.

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• 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
• particularly deficient in ocean obs.
• temporal and spatial scales?

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HWRF TEAM Gopal S. Qingfu Liu Bob T,
Veejay T. Y. Kwon, B. OConnor Isaac
Ginis, Morris Bender
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THANK YOU FOR YOUR ATTENTION
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HWRF Cycling System

1. Create a new HWRF domain based on the storm
   center position, and fill the outer nest and
   inner nest grids with guess data.
2. Run GSI regional analysis for both the outer nest
   and the inner nest, then merge the two nested
   data (we use a larger domain for inner nest
   analysis).
3. Run HWRF forecast to obtain 03h, 06h and 09h
   forecast fields.
4. Go back to Step 1.

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Guess Fields Creation

• Create a new HWRF domain based on the new storm
  center position, interpolate GFS analysis onto
  the new HWRF grids (outer nest 750x750, inner
  nest 60x60)
• Remove the storm vortex from GFS data
• Obtain the storm vortex from 6h HWRF forecast and
  correct its intensity
• Insert the modified 6h HWRF vortex back to the
  new HWRF grids at the observed position
• 5. If there are no 6h HWRF forecast, we will
  skip step 3, and replace the storm vortex with a
  bogus storm in step 4.

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Ocean initialization and assimilation

• Initial conditions from operational Atlantic
  forecast model, the
• Real Time Ocean Forecast System (RTOFS)
• Data is assimilated during the nowcast cycle of
  RTOFS
• Boundary conditions are derived from RTOFS
• Five day forecasts are sampled 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, AXBTs.

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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)

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Coupling / stresses

• URI and GFDL have developed a coupled
  atmosphere-wave- ocean model as a preparation for
  HWRF.
• Critical issue Stresses in high wind regime
• Observations
• Models
• URI, RSMAS

WAVEWATCH
URI
Powell et al, 2003