1. ATMOS. MODEL
(MM5/COAMPS/WRF)
OCEAN MODEL
(HYCOM or 3DUOM)
WAVE MODEL
(WAVEWATCH III or WAM)
Roughness length
Wind-induced stress
Surface fluxes
SST
SSH & current velocity
Wave-Induced stress
Coupled Atmosphere-Wave-Ocean Modeling System for Hurricane Predictions

2. Coupled Modeling System
MM5 (PSU/NCAR)
(vortex-following nests with 45, 15, 5, and 1.67 km grid spacing, NCEP analysis and AVHRR or TMI/AMSR-E SST)
WAVEWATCH III (NOAA/EMC)
(1/12o, 25 frequency bands, 48 directional frequency bands)
HYCOM (UMiami/NRL)
(1/12o, 22 vertical levels with 4-6 in the ocean mixed layer)
3DUOM (Price’s 3-D Upper Ocean Circulation Models)

4. (meter)

5. (meter)

7. Hurricane Frances

8. Tom Sanford’s floats

9. Float 1633: 50 km to Right in Highest Wind
Tom Sanford, APL/University of Washington

10. Landfall
Aug 27
Sept 6

11. Landfall

12. Coupled MM5-WAVEWATCH III
Roughness Length (non-directional)
t = tt + tw zo
zo - wave-age dependent
Stress Vector (directional)
Mx = - tx
My = - ty
tx , ty - components of stress from integral of
momentum input to the wave spectrum. V t

13. Wind-Wave Coupling Parameterization
Spectra Tail Parameterization:
X-component of stress from integral of momentum input to the spectrum:
Growth rate of each component from measurement of pressure-slope correlation
Spectrum of long waves from WAVEWATCH III; spectrum of short waves from fit to tail given below. a is adjusted to fit the highest modeled wavenumbers.
b is the spreading function for the short waves.

15. Hurricane Frances (2004) FR RR FR RR FL RL FL RL CD CD Ck Ck

17. Coupled
GPS Dropsondes
Uncoupled

18. Total Surface Heat Flux
Uncoupled
Coupled Atmos-Wave-Ocean

19. Coupled
Uncoupled

20. Coupled Atmosphere-Wave-Ocean Modeling
CBLAST-Hurricane
Coupled Atmosphere-Wave-Ocean Modeling
Conclusions
Atmosphere-Ocean coupling improves tropical cyclone intensity forecasts, especially at very high resolution when eyewalls are explicitly resolved.
Wind-Wave coupling contributes to storm asymmetry that very significantly from storm-to-storm.
We have developed and tested a number of air-sea coupling parameterizations for fully coupled atmosphere-wave-ocean modeling systems for hurricane prediction, which are designed to be general and easy to be implemented in both research and operational coupled models.