The Non-Boussinesq ROMS and Its Applications

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The Non-Boussinesq ROMS and Its The Non-Boussinesq ROMS and Its ApplicationsApplications

Y. Tony Song

Jet Propulsion Laboratory

Contents:

1. The development of non-Boussinesq ROMS (Hou, Caltech; Colberg, JPL)

2. GRACE, inter-ocean transport (Zlotnicki, JPL; Susanto, Lamont-Doherty)

3. Coupled earthquake-ROMS for tsunami prediction (Caltech & OSU)

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Grace

Ocean Bottom Pressure

TOPEX/Poseidon

Sea Surface Height

Stratified Ocean

Launched 2002

T/P-Jason provides SSH, T/P-Jason provides SSH, representing volume representing volume changes (changes (heat heat expansionexpansion), but most ), but most ocean models are ocean models are incompressible.incompressible.

GRACE measures ocean GRACE measures ocean bottom pressure, bottom pressure, representing water representing water mass mass changes, changes, but most but most models are not mass-models are not mass-conserving or conserving or topography-following.topography-following.

Hb dzgP

Observing Ocean’s Surface & Bottom

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ROMS vs non-Boussineq ROMS

Tony Song, January 2006

)()()1( sChHshsz cc

SCRUM/ROMS

1. S-coordinate (Song&Haidvogel 1994):

2. Sp-coordinate (Song&Hou 2006; Song et al. 2005):

)()()()1( 0' sCppsppspp cbcbs

Ocean-bottom-pressure model (non-

Boussinesq ROMS)

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Non-Boussinesq Global Ocean Model Results

• SOI (E---W): Atmospheric pressure Oscillation

• Nino3 (E---W): SST Oscillation

The strongest OBP signal in the

northern hemisphere

5 Tony Song, August 2006

GRACE-Observed Ocean Mass Changes

Sumatra earthquakesGreenland ice melting fast than previous thought

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Focusing on the North Pacific

7 Tony Song, October 2007

ROMS_NB Development

List:

• based on recent ROMS

• couple sea-ice

• couple earthquakes

• couple land loading

See Frank Colberg’s poster

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JGR-OceanJGR-Ocean special section (111, 2006): special section (111, 2006): Dynamic Processes and Dynamic Processes and Circulation in Yellow Sea, East China Sea, and South China SeaCirculation in Yellow Sea, East China Sea, and South China Sea

Tony Song, August 2004

100 O E 105 O E 110 O E 115 O E 120 O E 125 O E 130 O E

0 O N

5 O N

10 O N

15 O N

20 O N

25 O N

30 O N

35 O N

40 O N

C H I N A

Taiw

an

East C hinaSea

South C hina Sea

Luzon

C hangjiang R iver

Luzon S t

Tokara S t

N orth Pacific

Ryuky

u Is

Yellow Sea

BohaiSea

H ainan

G ulf o f Tonkin

Indo-C hinaPeninsula

G ulf o f Thailand

Kalim antan

Sulu Sea

Karimata S t

Malay Peninsu la

Tsushim a S t

Japan/East Sea

Taiw an S t

KCC

0m

50m

200m

1000m

5000m

Guest editors: Zheng (UM), Fang (FIO) & Song (JPL)

List of Papers for JGR Special Issue

1. Sea surface temperature variability in the China Seas from 1982 to 20032. Observations of coastal upwelling in summer 2000 in the northeastern South China Sea3. Current measurements and spectral analyses in the Luzon Strait during spring of 20024. Thermohaline circulation in the Deep South China Sea Basin inferred from oxygen distributions5. Measurements of the turbulent energy dissipation rate ε and an evaluation of the dispersion process

of the Changjiang Diluted Water in the East China Sea6. Numerical simulation of meandering, patch and lens structures of Changjiang Diluted Water in

Yellow Sea7. Analyses of Upper Layer Thickness Variation in the South China Sea from Satellite Altimeter Data

and In-situ Measurements 8. Estimate Interbasin Transport Using Ocean Bottom Pressure. Part I: Theory and Model for Asian

Marginal Seas9. Regional Wind and the Lombok Strait Throughflow10. Three-dimensional structure of the summertime circulation in the Yellow Sea from a wave-tide-

circulation coupled model11. Interannual variability of the gap in the Indo-Pacific warm pool over South China Sea associated with

ENSO and IOD12. Acoustic transmission in the cold eddy in the southern East China Sea13. Surface current field and seasonal variability of Kuroshio and adjacent regions derived from satellite-

tracked drifter data14. Development of Sub-surface Warm Water in East China Sea in Fall15. Variation of the Yellow Sea Warm Current and related eddies in winter16. Observation of the seasonal evolution of the Yellow Sea Cold Water Mass in 1996 – 199817. The mechanism of internal waves in the Luzon strait18. The development of ocean and ecosystem numerical models and applications to the Southern Yellow

Sea19. Current structures and their seasonal variation in Huanghai (Yellow) Sea and East China Sea20. Response of the South China Sea circulation to El Nino as seen from the variable-grid global ocean

model results21. The upwelling off Yangtze River estuary and adjacent sea in summer22. Interannual variation of the South China Sea surface fields in the recent decade from satellite

observations23. The upwelling system in the Yellow Sea and East China Sea: Results from Field Observations and

Numerical Modeling24. The current-vortex structure of the Southern East China Sea in Summer25. Winter Fronts in Taiwan Strait26. Origin and distribution patterns of Sediments in the Southern Yellow Sea27. A numerical study on dynamic mechanisms of seasonal temperature variability in the Yellow Sea28. The characteristics of hydrographic and chemical elements of the Yellow Sea and East China Sea in

summer, 1998

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Asian Marginal Seas & Their ConnectionsAsian Marginal Seas & Their Connections


Inter-basin transport is difficult to estimate because of its:

• complex geometry

• dependence on local and remote forcing

(a)

(b)

(d)

(c)

(Song, JGR-Oceans, 2006)

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Geostrophic and Hydraulic Control Geostrophic and Hydraulic Control


(b) Whitehead [1989] gives a simple method to estimate the mean transport (upper bound) by hydraulic control theory.

(a) Garret & Toulany [1982] gives a simple method to estimate the surface geostrophic transport.

otherwisepgWHH

f

g

RWforpHHf

g

Q

b

b

|3

2

)(5.0

2

2/3

1

21

Estimate strait transport by Combining (a) and (b):

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Seasonal VariabilitySeasonal Variability

Ocean Bottom pressure is necessary for a better estimate of the seasonal inter-basin transports


Based on SSH only Based on SSH and OBP

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Coupled Earthquake-Ocean Model for Tsunami Study


Related WorkRelated WorkSong et al., The 26 December 2004 tsunami source estimated from satellite radar altimetry Song et al., The 26 December 2004 tsunami source estimated from satellite radar altimetry

and seismic waves, and seismic waves, GRLGRL, , 3232, doi:10.1029/2005GL023683 (2005)., doi:10.1029/2005GL023683 (2005).Song et al., Horizontal impulses of continental slopes dictate the 26 December tsunami, Song et al., Horizontal impulses of continental slopes dictate the 26 December tsunami,

revised for revised for Ocean ModellingOcean Modelling (2007) (2007)Song, Y.T., Detecting tsunami genesis and scales directly from coastal GPS stations, Song, Y.T., Detecting tsunami genesis and scales directly from coastal GPS stations, GRLGRL, ,

3434, doi:10.1029/2007GL031681 (2007)., doi:10.1029/2007GL031681 (2007).Song and Han: Satellite observations challenging the long-held tsunami genesis theory, Song and Han: Satellite observations challenging the long-held tsunami genesis theory,

Review in Review in NatureNature (2007). (2007).

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Tsunami and Earthquake History

Zhang Heng (張衡 , 78 – 139 A.D.) was an astronomer, mathematician, inventor, and poet of the Eastern Han Dynasty in ancient China.

Famous for his invention of the first seismograph (132 A.D.)

Thucydides (460 – 400 B.C.) was a Greek historian of the Peloponnesian War.

Recorded the Aegean Sea tsunami (426 B.C.)

Seismometers can detect only earthquakes, but not a tsunami itself, which is dangerous to many coastal communities. When earthquake is coupled with ocean models on modern computers, they are able to provide early warnings for those coastal regions at risk.

14 Tony Song, January 2005

More recent tsunamis: No successful warning so far.

Date Location Magnitude Early Warning? Fatalities

26 Dec 2004

28 Mar 2005

Sumatra

Nias Island

9.2

8.7

no

yes

230,000

Panic evacuation (~100)

19 July 2006 West Java 7.7 no ~600

June 2005

May 2006

Nov 2006

Jan 2007

Mar 2007

California

Tonga

North Japan

North Japan

Solomon Is

7.1

7.8

8.3

8.1

8.0

yes

yes

Yes

Yes

?

False alarm

False alarm

False alarm

False Alarm

~30

Since 1982, tsunami warnings based on earthquake magnitude have produced false alarms 16 out of 16 in Pacific (U.S. Government Accountability Office, GAO-06-519).

State of Hawaii’s estimation: an evacuation from a tsunami alarm in 1996 would have cost the state $58.2 million in economic losses.

1. Introduction

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2. Tsunami Prediction System )(),()sin(),()cos()( 21

1 1

tStVYtVYDtu jkjkjkjkjkjkjk

n

j

n

kjk

seafloor motions

Predict Tsunami


16 Tony Song, January 2006

3. Tsunami Genesis TheorySong et al. (2007):Song et al. (2007): deriving tsunami-source energy directly from deriving tsunami-source energy directly from

ground motions.ground motions.

Conclusion 1:

Earthquake energy ≠ Tsunami energy

Conclusion 2: Lateral motions of continental slopes transfer the major tsunami energy

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4. GPS-Predicted Tsunamis

Directly detect the mechanism that generates tsunamis.

By-passing the earthquake-magnitude-based method that had often caused false alarms.


(validated by three historical events)

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5. Determine Tsunami Scales

• Earthquakes—Richter’s scale (magnitude)

• Hurricanes—Simpson’s scale (category)

• Tsunamis can be scaled (based on sqrt (ET) ~ tsunami height):

1. If ST < 5, local warning only.

2. If ST > 5, basin-wide warnings and modeling are needed.

3. Early warnings can be issued in 20 minutes after quake. Tony Song, January 2006

10log)5(log2 1010 TTT EES

Earthquake Magnitude Tsunami Energy(ET)

Tsunami Scale(ST)

Basin-wide Warning?

GPS Seismic GPS Seismic ST = 5 threshold

2004 Sumatra (Mw 9.2) 6.0e+15 J 5.2e+15 J 5.8 5.7 >> 5 Yes

1964 Alaska (Mw 9.2) 8.2e+15 J 5.9 >> 5 Yes

2005 Nias (Mw 8.7) 2.8e+14 J 2.2e+14 J 4.4 4.3 << 5 No

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6. Validations (1964 & 2005 Tsunamis)


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7. Proposed tsunami-detection Plan

Plan3. GPS detection system (~$5 millions) serves two purposes:

1. Detect tsunami potentials2. Monitor plate boundaries

Plan2. DART buoys: ~$50 millions Pacific only (does not protect people on the coastal side)

Plan1. Satellite-constellations: ~$300 millions (Nobody wands to pay for it)


1,440 GPS stations

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At United Nations

Description of Event: JPL’s tsunami prediction concept was selected and reported at UN’s EWC3, Mach 25~30, 2006, Bonn, Germany

German newspaper report: “Tension at the border” …Tony Song of NASA broke silence on Tuesday at the international early warning conference in Bonn. Before the event, former US president Bill Clinton and Federal Minister of Foreign Affairs Frank-Walter stone Meier and more than 1000 scientists urged to furnish as fast as possible warning systems for Tsunamis. But now Song demonstrated his colleague that they had not understood the cause of the giant waves correctly. According to the established theory a Tsunami develops, if the sea water gets an impact with a sea-quake transferred by the sea- bottom: The soil moves thereby like a piston perpendicularly upward, it is said. Song meanwhile found out that the Tsunamis was released on 26 December 2004 particularly when lateral breaking the soil….

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Summary


The development of non-Boussinesq ROMS has several important applications:

• Mass-related ocean climate studies• Geodedic-related applications (earth rotation, GPS, tsunami)• Hydrological applications (ice, land fluxes)

All of these topics are relevant to NASA’s missions.

Documents

The Non-Boussinesq ROMS and Its Applications