1. Shuyi S. Chen Joseph Tenerelli, Wei Zhao, Mark Donelan Rosenstiel School of Marine and Atmospheric Science University of Miami Coupled Atmosphere-Wave-Ocean Parameterizations for High-Winds Sponsored by the Office of Naval Research AMS 13 th Conf on Interactions of the Sea and Atmos., Portland, 9-13 August 2004

2. ATMOS. MODEL (MM5/COAMPS/WRF) OCEAN MODEL (HYCOM or 3DUOM) WAVE MODEL (WAVEWATCH III or WAM) Roughness length Wind-induced stress Surface fluxes and stress SST SSH & current velocity Wave-Induced stress Coupled Atmosphere-Wave-Ocean Modeling System for Hurricane Predictions LES Sea Spray Param. of spectral tail and drag coefficient Param. of wave dissipation Source function? Drop size distribution? Effects on turbulence? How do these affect exchange coefficients of enthalphy? What is the ratio of C K and C D ?

3. LKB (1979) What is the ratio of C K and C D ?

4. 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) (1/12 o, 25 frequency bands, 48 directional frequency bands) HYCOM (UMiami/NRL) (1/12 o, 22 vertical levels with 4-6 in the ocean mixed layer) 3DUOM (Price’s 3-D Upper Ocean Circulation Models) Coupled Modeling System

5. Model initialized on 00 UTC 11 Sep 1999 using the AVN analysis fields and the AVHRR Pathfinder SST 30 vertical levels, lowest half-sigma level about 12 m above the surface Four levels of nests, with grid spacing of 45, 15, 5, and 1.6 km, all but the coarsest mesh moving with the hurricane Modified surface flux parameterization based on Garratt (1992) and Pagowski and Moore (2000) MM5 Configuration

6. WAVEWATCH III Configuration 4-D Spectrum Model [(x, y), (k,  1/6 degree grid spacing 25 frequency bands (logarithmically spaced from 0.04-0.4 Hz) 48 directional frequency bands (evenly spaced by 7.5 o )

7. Hybrid Coordinate Ocean Model (HYCOM) one-way nested Western Atlantic-Gulf of Mexico- Caribbean Sea regional domain (with data assimilation of SSH prior to hurricane simulations) 1/12 degree grid spacing 22 Vertical layer, 4-6 layers in mixed layer with the 1 st layer at 3 meter MM5 atmospheric forcing, 8 September – 17 October 2002 (Hurricanes Isidore and Lili)

12. WW3Observed Open Ocean (Northeast)

13. WW3Observed Landfall (Southwest)

14. Roughness Length (non-directional)  =  t  w z o z o - wave-age dependent Stress Vector (directional) M x = -  x M y = -  y  x,  y - components of stress from integral of momentum input to the wave spectrum. Coupled MM5-WAVEWATCH III V 

15. Wind-Wave Coupling 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.  is adjusted to fit the highest modeled wavenumbers.  is the spreading function for the short waves.

16. Figure 4. Vorticity contours obtained via Digital Particle Image Velocimetry (DPIV) in the air flow over wind driven waves [Reul, 1998]. Both wave and air flow are from left to right. (Top) waves of gentle slope – non-separated flow. (Bottom) waves of steep slope – separated flow. Z(cm) 0 10 20 30 40 x (cm) 0 0 6 6 Drag coefficient in high-wind conditions (Donelan et al. 2004)

21. Hurricane Floyd (1999)

23. ObservedUncoupledFully Coupled

24. Emanuel (1995) found that Ck/Cd > 1 for intensifying storms. CBLAST observed Ck/Cd < 1 (C. Fairall). Uncoupled Ck/Cd Coupled Ck/Cd

27. Before Bonnie After Bonnie.........

30. Net Heat Flux Uncoupled Coupled Ocean Coupled Wave-Ocean

31. Observed UncoupledCoupled

32. Temperature Profiles Open Ocean Gulf Stream

33. Hurricanes Isidore and Lili (2002) in tandem

34. Hurricane Lili (2002)

35. SST Before Isidore HYCOM Satellite

36. HYCOM Satellite SST Cooling After Isidore

37. HYCOM Satellite SST Cooling After Lili

38. Loop CurrentGulf Common Water IsidoreLiliIsidoreLili

39. CBLAST-Hurricane Coupled Atmosphere-Wave-Ocean Modeling 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. Simple 3DUOM+Satellite SST works well over the open ocean. However, full ocean model, e.g. HYCOM, is needed for the coastal regions and over the Gulf Stream and warm eddies. Conclusions