Nobuhito Mori and Junichi NinomiyaDisaster Prevention Research Institute

Kyoto University, Japan

CollaboratorsJohn C. Warner (USGS)

Eric D’Asaro (U Washington)C.T Chen (NCDR, Taiwan)

Metrological Research Institute, Japan+ Central Weather Bureau, Taiwan

COAWST in Kyoto

August 25-28, WHOI

On Going Studies

Typhoon modeling: WRF-ROMS-SWAN Target

Sensitivity of wave effects via z0air, z0

water and TKE Current status

Typhoon Mellor (2010), Fanapi (2010) plus 4-6 events Resolution

ROMS: 1-5 km

Wave effects on current: ROMS-SWAN Target

Directional wave effects for vortex force Current status

Theory and preliminary test Resolution

ROMS: about 50-100 m

Momentum roughness length at ASI3 |

Drag coefficient

Momentum flux

Thermal roughness length

Surface exchange coefficient

Sensible heat

Latent heat, etc.

Momentum roughness length

Viscous term Wave term

Charnock:Calm sea ...Long swellChoppy wind sea

Ocean

Atmosphere

3 |

By Elodie CHARLES

Impact of wave coupling: Charnock vs TY

2014/8/21

Mean(10/6 21:00 - 10/7 3:00)

Friction Velocity, Sensible/Latent heat fluxRear Side

2009/10/6 18:00 – 10/7 00:00 UTC

Oost results have peak value at closer to center of typhoon.

The larger friction velocity and heat flux are estimated by with wave model

U10 [m/s]

u* [m/s]

Sensible heat [W/m2]

Latent heat [W/m2]

Z0 byCharnockTaylor-YellandOostDrennan

U10 [m/s]

u* [m/s]

Sensible heat [W/m2]

Latent heat [W/m2]

Application to climate change study

Case study of TC Haiyan SSTCase study of Seto-Inland Sea in Japan

Present

2100

Random wave effects on current

COAWST only uses Hs and Tm01 from SWAN to ROMS

Kumer et al. (2012)

Stokes driftTheory

kh=0.50JONSWAP g=2.0Mitsuyasu N=10

kh=2.0JONSWAP g=2.0Mitsuyasu N=10

Implementation of random wave effects to COAWST

Unidirectional regular wave stokes drift

Multidirectional irregular wave stokes drift

Methodology Assuming directional

spectra shape and communicate frequency and directional bandwidth by coupler

Communicate directional spectra directly

0mkak p

Inlet Test: Snapshot of ubar and vbar

2D Irregular1D Regular