Hurricane forecasts with Regional NMMB: Impact of HWRF Physics Weiguo Wang and Vijay Tallapragada...
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Transcript of Hurricane forecasts with Regional NMMB: Impact of HWRF Physics Weiguo Wang and Vijay Tallapragada...
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Hurricane forecasts with Regional NMMB: Impact of HWRF Physics
Weiguo Wang and Vijay Tallapragada EMC/NCEP/NOAA, College Park, MD 20740
Mar. 2015
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Outline
• Importance of physics in Hurricane forecast
• HWRF physics packages into NMMB
• Hurricane simulations with regional NMMB
+ NMMB with ‘NAM physics’ vs with ‘HWRF physics’
+ NMMB with ‘HWRF phys’ vs operational HWRF
• Summary and Future work
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Introduction+ The Nonhydrostatic Multi-Scale Model on B grid (NMMB) is the second generation of nonhydrostatic models developed at NCEP. It performs well, and replaced WRF-NMM (HWRF’s dynamic core) years ago in NAM.
+ NMMB has the potential to continue to advance our hurricane forecast capability, given good parameterizations of hurricane physics.
+ Storm intensity and track are sensitive to the parameterizations of physical processes such as PBL, convection, microphysics, radiation, even land surface exchange
+ HWRF physics package has been well tested, and performed well to simulate hurricane structure in addition to intensity and track.
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HWRF physics to NMMBFollowing physics schemes used in operational HWRF have been added to NMMB:
1. GFSPBL scheme 2. GFDL surface layer plus GFDL land surface scheme3. SAS scheme 4. MESO-SAS scheme5. Add empirical z0 for hurricane to MYJ surface scheme
NMMB has “fer”, “fer_high” micophysics schemes, and “gfdl”, “rrtmg” for radiation; those are very similar to HWRF’s.
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How to use
- Options in configure files #
turbulence: gfspblhur convection: sashur sfc_layer: gfdl
land_surface: gfdlslab
- Tunable variables can be changed in configure files, default values are those currently-used in HWRF#
RUN_TC=.true. ! true='run hurricane'sas_pgcon var_ricsas_shal_pgcon coef_ric_lshallow_conv coef_ric_ssas_shalconv ALPHAsas_mass_flux SFENTHsas_mommix DISHEAT
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Operational HWRF vortexInitial conditions
GFS 0.5-degree dataBoundary Conditions
NPS
NMMBconfigure_file_d01
namelist.nps
Post/Tracker
Graphics
Can be replaced by spectral data
Will be replaced by NMMB-DA/INIT Flow chart for tests
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Configuration 01“Hwrfphys”
turbulence: gfshursfc_layer: gfdlland_surface: gfdlslabconvection: sashurmicrophysics: fershortwave: gfdllongwave: gfdl
Configuration 02“NAM-like”
turbulence: myjsfc_layer: myjland_surface: noahconvection: bmjmicrophysics: fershortwave: gfdllongwave: gfdl
NMMB Hurricane simulations27-9-3 domains, 43-level, feedback=0.5
No ocean, no DA
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Compare NMMB using HWRF phys with Operational HWRF
NMMB (red) Intensity very close to HWRF (purple), and even better timing of max
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Another NMMB run:
turbulence: gfspblsfc_layer: myj (z0 modification)land_surface: noah
Comparison of myj/noah-LSM and GFDL/slab from NMMB runs.
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Summary • With HWRF phys package, regional NMMB can well
simulate hurricane structure, intensity and track, showing potential to further advance NCEP capability to hurricane forecast.
• Comparison with physics options in NAM shows importance of using good physics parameterizations for hurricanes.
• Future work: improve nest motion algorithm, other components (e.g., DA + init) from HWRF system, …