Progress in Developing Coupled Tropical Cyclone-Wave-Ocean Models for Operational

Implementations at NOAA and Navy

Isaac GinisMorris Bender, Tetsu Hara, Richard Yablonsky, Biju Thomas,

Yalin Fan, Jian-Wen Bao, Chris Fairall, Laura Bianco

University of Rhode Island, NOAA/GFDL, NOAA/ESRL

Progress in Developing Coupled Tropical Cyclone-Wave-Ocean Models for Operational

Implementations at NOAA and Navy

Isaac GinisMorris Bender, Tetsu Hara, Richard Yablonsky, Biju Thomas,

Yalin Fan, Jian-Wen Bao, Chris Fairall, Laura Bianco

University of Rhode Island, NOAA/GFDL, NOAA/ESRL

Interdepartmental Hurricane Conference, Savannah, GA March 1-4, 2010

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Operational Coupled Operational Coupled Tropical Cyclone-Ocean ModelsTropical Cyclone-Ocean Models

Operational Coupled Operational Coupled Tropical Cyclone-Ocean ModelsTropical Cyclone-Ocean Models

• 20012001 – GFDL/POM at NCEP in Atlantic ocean (3D – GFDL/POM at NCEP in Atlantic ocean (3D coupling).coupling).

• 20042004 – GFDL/POM at NCEP in Eastern and Central – GFDL/POM at NCEP in Eastern and Central Pacific (1 D couplingPacific (1 D coupling). ).

• 20072007 – HWRF/POM at NCEP in Atlantic ocean (3D – HWRF/POM at NCEP in Atlantic ocean (3D coupling).coupling).

• 20082008 – GFDN/POM at FNMOC in Atlantic ocean (3D – GFDN/POM at FNMOC in Atlantic ocean (3D coupling) and all other oceans(1D coupling)coupling) and all other oceans(1D coupling)

• 20092009 – GFDN/POM at FNMOC in the Northern – GFDN/POM at FNMOC in the Northern Pacific ocean (3D coupling). Pacific ocean (3D coupling).

Atmospheric Model

Ocean Model

Air-Sea Interface

sasaDa UUUUC sasaHH TTUUCQ

sasaEP

VE qqUUC

C

LQ

Momentum flux (τ)Sensible heat flux (QH)Latent heat flux (QE)

Momentum flux (τ)

Wind speed (Ua)Temperature (Ta)Humidity (qa)

Surface current (Us)SST (Ts)

Conventional Coupling Between Tropical Cyclone and Ocean Models

Conventional Coupling Between Tropical Cyclone and Ocean Models

Atmospheric Boundary Layer

Wave Boundary (Surface)Layer

Momentum & KE Flux

Turbulence Sea Sprays

BubblesMomentum & KE Flux

Gas Flux

Nonbreaking Waves Breaking Waves

Wave induced stressReynolds stress

(Langmuir) Turbulence

Air-Sea Interface

Heat & Humidity Flux

Airflow separationIntermittency

Intermittency ofMomentum & KE injection

Stokes drift

Ocean Boundary Layer

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New Coupled Tropical Cyclone-Ocean Framework(being implemented into HWRF and GFDN models)

TC model: air-sea heat and momentum fluxes and sea spray source functions explicitly include SST, sea-state dependence and ocean current effects.Wave model: is forced by sea-state dependent momentum flux and includes ocean current effects.Ocean model: is forced by sea-state dependent momentum fluxes.

Fan, Ginis, Hara & Walsh J. Phys. Oceanogr. (2009)

Hurricane Ivan (2004)

Envisat-1ERS - 2

Effect of Wind-Wave-Current Interaction on Hurricane-Generated Waves

21 UTCSept. 14

2:40 UTCSept. 15

ModelTemp 70 m Sept. 12

Satellite altimetry

Sept.12

Impact of Loop Current and Warm Core Eddy on Hurricane-Generated Surface Waves

21:00 UTCSept.14

2:40 UTCSept. 15

WW3 significant wave height difference with and without LC/WCE

Significant wave height (Hs) along flight track

LCLC

WCEWCE

(m) (m)

Impact of Loop Current and Warm Core Eddy on Hurricane-Generated Surface Waves

LCLC WCEWCE

Significant waveheight

Ocean current difference with andwithout LC/WCE

21:00 UTCSept.14

2:40 UTCSept.15

Dominant wave direction

Impact of Loop Current and Warm Core Eddy on Hurricane-Generated Surface Waves

• GFDN is run at FNMOC of NOGAPS global model. Ocean model is initialized from Navy’s NCODA analysis

• Model physics changes implemented in GFDN in 2008 compared to NOAA’s GFDL model:

- Penetrative solar radiation included in ocean model

- Bug fixed in Ch calculations and coupling interpolation

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Navy’s Operational GFDN ModelNavy’s Operational GFDN Model

• Atmospheric grid resolutions

• Princeton Ocean Model grid resolutions

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Development of High-Resolution GFDNDevelopment of High-Resolution GFDN

Operational GFDN:

Mesh 1: 75ox75o – 1/2o res

Mesh 2: 11ox11o – 1/6o res

Mesh 3: 5ox5o – 1/12o res

High-Resolution GFDN

Mesh 1: 75ox75o – 1/2o res

Mesh 2: 11ox11o – 1/6o res

Mesh 3: 5ox5o – 1/18o res

Operational GFDN: 1/6o High-Resolution GFDN: 1/12o

Wind Speed Cross-Section (72h) Katrina: August 25th, 0z forecast

Improved Structure with Higher Resolution

1/12th Degree Resolution 1/18th Degree Resolution

Surface Winds (72 hr)Katrina: August 25th, 0z forecastImproved Structure with Higher Resolution

1/12th Degree Resolution 1/18th Degree Resolution

Accumulated precipitation (47-48 hr)Katrina: August 25th, 0z forecastImproved Structure with Higher Resolution

1/12th Degree Resolution 1/18th Degree Resolution

• 266 forecasts in 2009 were rerun in the Western Pacific using the GFS global model for initial and boundary conditions.

• No changes were made in the ocean model initialization.

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Effect of Global Model on GFDN Forecasts in Western Pacific

Effect of Global Model on GFDN Forecasts in Western Pacific

Average Track Errors

NORMALIZED ERRORS

RELATVIE TOCLIPPER

48 hr 72 hr 96 hr

GFDN from NOGAPS (black)

GFDN from GFS (red)

72 HOUR

Track Errors for Each Storm

Typhoon Nida (25W)

20 N

10N130E 140E

1 GFDN

2 NOGAPS

3 GFS

4 GFDN FROM GFS

Nov. 24th, 18z

30 N

20N

Nov. 25th, 12z140E 150E

1 GFDN

2 NOGAPS

3 GFS

4 GFDN FROM GFS

1 GFDN

2 NOGAPS

3 GFS

4 GFDN FROM GFS

Nov. 26th, 00z Nov. 26th, 12z

20 N

30 N

20 N

1 GFDN

2 NOGAPS

3 GFS

4 GFDN FROM GFS

NORMALIZEDERRORS

RELATIVE TOST5D

Average Intensity Error

72 HOUR

Intensity Errors for Each Storm

GFDN from NOGAPS (black)

GFDN from GFS (red)

• Increased horizontal resolution in GFDN model improves horizontal and vertical structures in simulated tropical cyclones. Initial test results suggest that some model physics may need to be retuned for better performance.

• Experimental GFDN runs using GFS global model in the Western Pacific show improved forecasts skill for both track and intensity compared to the operational GFDN model

• Coupling with the WAVEWATCH wave model and introducing sea spray effects is in progress.

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ConclusionsConclusionsConclusionsConclusions

Track Errors in GFDN and GFSfor Each Storm

72 HOUR TRACKERROR

120 HOUR TRACKERROR

GFS (black) GFDN from GFS (red)

Typhoon CHOI-WAN (15W)

1 GFDN

2 NOGAPS

3 GFS

4 GFDN FROM GFS

Sep. 12th, 12z Sep. 12th, 18z

1 GFDN

2 NOGAPS

3 GFS

4 GFDN FROM GFS

Sep. 13th, 6z Sep. 13th, 18z

20 N

140 E 150 E

20 N

20 N

30 N

20 N

150 E 140 E150 E 140 E

150 E 140 E

1 GFDN

2 NOGAPS

3 GFS

4 GFDN FROM GFS

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