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Coupled Hurricane Atmosphere-Ocean Coupled Hurricane Atmosphere-Ocean Modeling System Modeling System HWRF-HYCOMHWRF-HYCOM

and and Hurricane Forecast PerformanceHurricane Forecast Performance

Hyun-Sook Kim

B. Hundermark, D. Iredell, Y. Kwon, L. Liu, C. Lozano, J. O’Connor, N. Surgi, V. Tallapragada, B. Tuleya, and

Z. Zhan

Marine Modeling and Analysis Branch

Environmental Modeling Center (EMC)/NCEP/NOAA

5200 Auth Road

Camp Springs, MD 207641

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meld

ATMOS.

HWRFHWRF

O(9 & 27 km)

OCEAN

HYCOMHYCOM–regional

O(8~14 km)

RTOFS*

(HYCOM–Basin)

O(4~17 km)

Parametric Winds

BC

Data Assimilation (SST, SSH,

Hydro.Graphic.Profiles) using 2D/3DVAR

SST

* Wind-stress* Heat Fluxes* Precipitation* Atm. Pressure

HWRF-HYCOMHWRF-HYCOM

GFS: O(25 km) IC

• Real-Time

Ocean Forecast System

http://polar.ncep.noaa.gov/ofs

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Differences HWRF-POM

(Operational HWRF)HWRF-HYCOM

5. IC RTOFS (daily run indpt)

Remote sensing SST/SSH/Feature model to provide meso-scale features in GOM, and Cold wake

6. BC GDEM RTOFS (daily run indpt)

2. Resolution O(20 km) & 23 levels O(8-14 km) & 26 hybrid layers

7. Nowcast Only Init. Stage GFS + Parametric Winds

3. Tides No Yes

4. Mixing Mellor-Yamada Level 2.5 GISS

Ready to couple tide & storm surge models

Update a storm location and intensity; Data assim.

1. Ocean Model POM HYCOM

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HWRF-HYCOM: Model Domains in Atlantic Ocean

O(4-17 km)

O(8-14 km)

O(~27 km)

& HWRF-Nest Moving domain (10 x 10o @4-km Resolution)

Dynamic, depending on a storm location

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1. Explicit representation of waves: 3-way coupling atmosphere-

ocean-waves (HWRF-HYCOM-WAVEWATCH III).

2. Eddy Resolving Global Ocean Modeling coupled with Ice

model (1/12o) to provide IC/BC to Basin-scale Models, e.g.,

Atlantic RTOFS, Hurricane Eastern Pacific Ocean Model

(HYCOM in collaboration with Navy).

3. Full data assimilation cycle in the Regional Ocean Hurricane

Models.

4. Increase horizontal and vertical resolution in the Regional

Ocean Hurricane Models.

Work in progress to support operational Hurricane forecast

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HWRF-HYCOM HWRF-HYCOM simulationsimulation

for for

KatrinaKatrina

Compared with

6-hourly GOES SST

(http://svs.gsfc.nasa.gov/vis/a000000/a003200/a003222/

index.html)

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Year stormSaffir-

Simpson scale

2005

Dennis 4

Emily 4

Katrina 5

Philippe 1

Rita 5

Wilma 5

2007 Dean 5

2008

Gustav 4

Hanna 1

Ike 4

Kyle 1

Test Cases

& More …

being presented

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TrackTrack Forecast Skill Comparison:Forecast Skill Comparison:

Katrina

Rita

Gustav Kyle

Conclusion:

Comparable to Op.

Coherent Forecast

Summary:

Error is at the same order of magnitude;

Error bars are consistently smaller

Black – HYCOM

Red – Operational

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IntensityIntensity Forecast Skill Comparison : Forecast Skill Comparison :

Katrina Rita

Gustav Kyle

Black – HYCOM

Red – Operational

Summary:

Error is at the same order of magnitude;

Error bars are consistently smaller

Conclusion:

Comparable to Op.

Coherent Forecast

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Example of Individual cycle performance

Katrina

BestBest: NHC

fKat05fKat05: HWRF-HYCOM

H08H08: Operational HWRF

Loop Current

Loop Current

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1. Ocean Response: SST

Time

Po

siti

on

SST loss rate (average):

For a major Hurricane,

e.g. Katrina

~0.3oC/6-hr

For a weak storm,

e.g. Kyles

~0.1oC/6-hr

Katrina

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2. Ocean Response: MLD

MLD variation at storm passage:

Relatively large deepening for stronger storms

Relatively large variation at shallower waters

Size @34-kt

Rita

Rita

Kyle

Loop Currents

Eddy

GS

LCEddy

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SST feedback: Snap Shot Analysis

Rita, a strong storm Kyle, a weak storm

Ut: ~5 m/s

LH Flux: ~3000 W/m2

(SST=29.6oC)

MLD: 1.2 m/6-hr

SST: -0.3oC/6-hr

Ut: ~8 m/s

LH Flux: ~1000 W/m2

(SST=27.7oC)

MLD: 0.4 m/6-hr

SST: -0.1oC/6-hr

Latent Sensible

SST tau

Latent Sensible

tauSST

Latent Sensible

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Example of Realistic Realization of Oceanic ResponseExample of Realistic Realization of Oceanic Response

Cold Wake

Inertial Waves

km5002/

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PlanPlan for Years 2009 & …: for Years 2009 & …:

C. 3-way coupling HWRF-HYCOM-WAVEWATCH IIIC. 3-way coupling HWRF-HYCOM-WAVEWATCH III

D. Global Model (1/12D. Global Model (1/12oo) for IC/BC ) for IC/BC

A. Further Improvements in the System to increase A. Further Improvements in the System to increase Track and Intensity Forecast SkillTrack and Intensity Forecast Skill

B. Transition to operationsB. Transition to operations

1.1. Real time exercises for 2009 Real time exercises for 2009

2.2. Operational for 2010, if accepted Operational for 2010, if accepted