![Page 1: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/1.jpg)
Generalized vertical Coordinate Ocean Generalized vertical Coordinate Ocean ModelModel
for Multi-Scale, Non-Boussinesq or Boussinesq Applicationsfor Multi-Scale, Non-Boussinesq or Boussinesq Applications
Y. Tony Song Y. Tony Song Jet Propulsion Laboratory, California Institute of Jet Propulsion Laboratory, California Institute of
TechnologyTechnology
Sponsored by NASA and ONR
![Page 2: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/2.jpg)
MotivationMotivation• How may ocean How may ocean
models do we have?models do we have?
• A lot; they differ simply A lot; they differ simply by their coordinate by their coordinate formulation.formulation.
• All of them solve the All of them solve the same ocean equationssame ocean equations
Generalized vertical Coordinate Equations
zz BH
![Page 3: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/3.jpg)
Understanding/predicting ocean dynamics Understanding/predicting ocean dynamics needs both observations and modelsneeds both observations and models
• Satellite observationsSatellite observations give synoptic view give synoptic view of the global oceanof the global ocean
• Based on remote Based on remote sensing technologysensing technology
• With amazing With amazing accuracyaccuracy
• Ocean modelsOcean models give 3-dimensional give 3-dimensional structure of the oceanstructure of the ocean
• Based on computer Based on computer technologytechnology
• With possible errors With possible errors (inconsistent with (inconsistent with satellite measurements)satellite measurements)
![Page 4: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/4.jpg)
Problems:Problems:
• T/P & Jason provide SSH, representing T/P & Jason provide SSH, representing volume changes (volume changes (heat expansionheat expansion), but ), but most models are incompressible most models are incompressible (Boussinesq).(Boussinesq).
• GRACE measures ocean bottom GRACE measures ocean bottom pressure, representing water pressure, representing water mass mass changes, changes, but most models are not mass but most models are not mass conserving.conserving.
![Page 5: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/5.jpg)
Model Errors:Model Errors:
1.1. Numerical Error:Numerical Error: Conventional single-coordinate model Conventional single-coordinate model has difficulties to represent multi-scale has difficulties to represent multi-scale ocean dynamics & topography ocean dynamics & topography accurately.accurately.
2.2. Representation Error:Representation Error:Boussinesq approximations do not Boussinesq approximations do not represent real ocean physics (e.g. heat represent real ocean physics (e.g. heat expansion & freshwater flux) and is expansion & freshwater flux) and is inconsistent with T/P and GRACE data.inconsistent with T/P and GRACE data.
![Page 6: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/6.jpg)
Reduce representation errors Reduce representation errors by by non-Boussinesqnon-Boussinesq formulationformulation
Reduce numerical errors by the generalized
coordinate
The New Model Configuration
SCRUM (Song&Haidvogel
1994)
Non-Boussinesq
ROMS
(Song 2002)
GCOM
![Page 7: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/7.jpg)
Two analytical s/sp—coordinate systems
shallow deep
5000m
10mh
S-coordinate (Song&Haidvogel 1994):
Sp-coordinate (Song 2002):
)()()()1( 0' sCppsppspp cbcbs
)()()1( sChHshsz cc
![Page 8: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/8.jpg)
Z-levels
S-levels BBL
SBL
Default Model Structure•All-in-one capability in general coordinate All-in-one capability in general coordinate systemsystem
•Truly compressible ocean model (Truly compressible ocean model (non-non-BoussinesqBoussinesq))
Flexible for coupling
Open Ocean
Hz—depth metricBz—Boussinesq
factor
![Page 9: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/9.jpg)
Heat expansion /contractio
n
Sea Surface
JPL Compressible Ocean Model
GRACE
• Topography-following & non-Boussenesq
• Consistent with GRACE and T/P observations
Bottom
TOPEX
![Page 10: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/10.jpg)
H L
Study 1. Bottom Pressure Waves Detected in Tropical Pacific (Song & Zlotnicki, GRL 2003)
Tropical Instability Eddy
Thermocline
Bottom Pressure Waves
![Page 11: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/11.jpg)
More comparison with T/P dataMore comparison with T/P data
![Page 12: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/12.jpg)
Study 2. Simulating ENSO with non-Boussinesq/Boussinesq
0.5°C Difference
due to Boussines
q
Simulated almost all the ENSO
events
![Page 13: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/13.jpg)
Study 3. Multi-Scale Modeling System for Coastal Oceans
Basin-scale 50-km in p-coordinate
Regional scale 10-km in z-
Coastal scale 1-km
Coastal can not be cut off from open ocean, therefore multi-scale modeling capability is needed
Ocean color
![Page 14: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/14.jpg)
SummarySummary• A new model with combined topography-A new model with combined topography-
following and non-Boussineq features is following and non-Boussineq features is developed for better representing T/P & developed for better representing T/P & GRACE data.GRACE data.
• Using the new model, we detected ocean Using the new model, we detected ocean bottom pressure waves in Tropical Pacific.bottom pressure waves in Tropical Pacific.
• We have also developed a multi-scale We have also developed a multi-scale coastal ocean modeling system for the coastal ocean modeling system for the coastal region off Southern California & coastal region off Southern California & Mexico.Mexico.
![Page 15: Y. Tony Song Jet Propulsion Laboratory, California Institute of Technology](https://reader036.vdocuments.mx/reader036/viewer/2022062423/56814d80550346895dbaddfe/html5/thumbnails/15.jpg)
Related PublicationsRelated PublicationsSong, Y. T. and D. B. Haidvogel, A semi-implicit ocean circulation model using a Song, Y. T. and D. B. Haidvogel, A semi-implicit ocean circulation model using a
generalized topographygeneralized topography-following coordinate. -following coordinate. J. Comput. PhysJ. Comput. Phys., 115, 228-244, 1994. ., 115, 228-244, 1994.
Song, Y. T., A Song, Y. T., A general pressure gradientgeneral pressure gradient formulation for ocean models, Part I: Scheme formulation for ocean models, Part I: Scheme design and diagnostic analysis. design and diagnostic analysis. Mon. Wea. RevMon. Wea. Rev., 126, 3213-3230, 1998.., 126, 3213-3230, 1998.
Song, Y. T. and D. Wright, A Song, Y. T. and D. Wright, A general pressure gradientgeneral pressure gradient formulation for ocean models, formulation for ocean models, Part II: Energy, momentum, and bottom torque consistency. Part II: Energy, momentum, and bottom torque consistency. Mon. Wea. RevMon. Wea. Rev., 126, ., 126, 3231-3247, 1998.3231-3247, 1998.
Song, Y. T., Computational design of the Song, Y. T., Computational design of the general coordinategeneral coordinate ocean model for multi-scale ocean model for multi-scale compressiblecompressible or incompressible flow applications, or incompressible flow applications, J. Atmos., Ocean Tech.J. Atmos., Ocean Tech., , submitted, 2002.submitted, 2002.
Song, Y. T. and V. Zlotnicki, Ocean bottom pressure waves detected in the Tropical Song, Y. T. and V. Zlotnicki, Ocean bottom pressure waves detected in the Tropical Pacific, Pacific, GRLGRL, submitted, 2003., submitted, 2003.