June 2025

Welcome to interactive presentation, created with Publuu. Enjoy the reading!

Oceanography | Vol. 38, No. 2

34

SUMMARY AND CONCLUSIONS

The TFO-HYCOM project was a cross-disciplinary investigation

into the modeling of internal tides and high-frequency IGWS

that explored their sensitivity to grid spacing, energy transfer,

and dissipation; the impacts of tidal forcing in ocean simulations

on sound speed structure and acoustic propagation; and the

ability to use DL techniques to replicate tidally forced structure.

The inclusion of tidal forcing in global ocean models improved

the representation of the ocean state and had a direct impact on

sound speed at horizontal scales from kilometers to hundreds of

kilometers and timescales on the order of a few to several hours.

HYCOM simulations run with tides had greater sound-speed

variance that was more consistent with observations. These

impacts were sensitive to vertical and horizontal discretization,

as were the ability of the simulations to resolve IGW interactions

and energy transfer. Further investigations into the impacts of

internal wave modeling choices on acoustic propagation could

also be made by expanding acoustic frequency ranges, looking at

acoustic arrival times, or comparing model results with observa­

tional studies. As running models at high resolution is compu­

tationally expensive, machine learning techniques may facilitate

predictions of IGW impacts on ocean state in the future.

We have focused on the impacts of IGWs on sound; how­

ever, global ocean models are further used by stakeholders with

diverse interests, such as the dispersal of biogeochemical tracers

and biological productivity. As global operational models begin

to include tidal forcing and incorporate finer grid spacing, it is

important to understand how they represent physical processes

and how energy cascades through the internal wave spectrum.

The ability to resolve IGWs in global ocean models has filter-​

down effects to several other fields such as ocean biological-​

physical interactions and ecosystem modeling. At shallow coastal

locations, where biological productivity and fresh­water input are

large, the ability to resolve these IGW processes is important to

understanding ecosystem dynamics. Among the range of their

impacts, IGWs can alter distributions of organisms such as phy­

toplankton and chlorophyll, increase or decrease biological pro­

ductivity, and alter predator-prey relationships (e.g., Evans et al.,

2008; Lucas et al., 2011; Greer et al, 2014; Garwood et al., 2020).

Having criteria for how IGWs can be resolved in a global model

with a certain discretization will help interpret how well a model

captures IGW energy transfer and the possible effects this may

have on sound speed variability and ecosystem dynamics.

REFERENCES

Ansong, J.K., B.K. Arbic, H.L. Simmons, M.H. Alford, M.C. Buijsman, P.G. Timko, and

A.J. Wallcraft. 2018. Geographical distribution of diurnal and semidiurnal para­

metric subharmonic instability in a global ocean circulation model. Journal of

Physical Oceanography 48:1,409–1,431, https://doi.org/10.1175/JPO-D-17-0164.1.

Arbic, B.K., S.T. Garner, R.W. Hallberg, and H.L. Simmons. 2004. The accuracy of

surface elevations in forward global barotropic and baroclinic tide models. Deep

Sea Research Part II 51:3,069–3,101, https://doi.org/10.1016/j.dsr2.2004.09.014.

Arbic, B.K, J.G. Richman, J.F. Shriver, P.G. Timko, E.J. Metzger, and A.J. Wallcraft.

2012. Global modeling of internal tides within an eddying ocean gen­

eral circulation model. Oceanography 25(2):20–29, https://doi.org/10.5670/

oceanog.2012.38.

Barkan, R., K.B. Winters, and J.C. McWilliams. 2017. Stimulated imbalance and the

enhancement of eddy kinetic energy dissipation by internal waves. Journal of

Physical Oceanography 47(1):181–198, https://doi.org/10.1175/JPO-D-16-0117.1.

Bell, T.H. Jr. 1975. Topographically generated internal waves in the open ocean.

Journal of Geophysical Research 80(3):320–327, https://doi.org/10.1029/

JC080i003p00320.

Bleck, R. 2002. An oceanic general circulation model framed in hybrid isopycnic-​

Cartesian coordinates. Ocean Modelling 4:55–88, https://doi.org/10.1016/

S1463-5003(01)00012-9.

Buijsman, M., G.R. Stephenson, J.K. Ansong, B.K. Arbic, M. Green, J.G. Richman,

J.F. Shriver, C. Vic, A.J. Wallcraft, and Z. Zhao. 2020. On the interplay between

horizontal resolution and wave drag and their effect on tidal baroclinic mode

waves in realistic global ocean simulations. Ocean Modelling 152:101656,

https://doi.org/10.1016/j.ocemod.2020.101656.

Buijsman, M.C., M.A. Abdulfatai, B.K. Arbic, E.P. Chassignet, L. Hiron, J.F. Shriver,

M. Solano, D. Varma, and X. Xu. 2025. Energetics of (super)tidal baroclinic

modes in a realistically forced global ocean simulation. ESS Open Archive,

https://doi.org/10.22541/essoar.173939615.50210043/v1.

Chassignet, E.P., H.E. Hurlburt, O.M. Smedstad, G.R. Halliwell, A.J. Wallcraft,

E.J. Metzger, B.O. Blanton, C. Lozano, D.B. Rao, P.J. Hogan, and A. Srinivasan.

2006. Generalized vertical coordinates for eddy-resolving global and coastal

ocean forecasts. Oceanography 19(1):118–129, https://doi.org/10.5670/

oceanog.2006.95.

Chassignet, E.P., and X. Xu. 2017. Impact of horizontal resolution (1/12° to 1/50°)

on Gulf Stream separation, penetration, and variability. Journal of Physical

Oceanography 47:1,999−2,021, https://doi.org/10.1175/JPO-D-17-0031.1.

Colosi, J.A., and S.M. Flatté. 1996. Mode coupling by internal waves for multime­

gameter acoustic propagation in the ocean. Journal of the Acoustical Society of

America 100(6):3,607–3,620, https://doi.org/10.1121/1.417334.

Dematteis, G., K. Polzin, and Y.V. Lvov. 2022. On the origins of the oceanic

ultraviolet catastrophe. Journal of Physical Oceanography 52(4):597–616,

https://doi.org/​10.1175/JPO-D-21-0121.1.

Dushaw, B.D. 2022. Surprises in physical oceanography: Contributions from ocean

acoustic tomography. Tellus A 74(1):33–67, https://doi.org/10.16993/tellusa.39.

Dzieciuch, M., W. Munk, and D.L. Rudnick. 2004. Propagation of sound through

a spicy ocean, the SOFAR overture. Journal of the Acoustical Society of

America 116(3):1,447–1,462, https://doi.org/10.1121/1.1772397.

Evans, M.A., S. MacIntyre, and G.W. Kling. 2008. Internal wave effects on

photosynthesis: Experiments, theory, and modeling. Limnology and

Oceanography 53(1):339–353, https://doi.org/10.4319/lo.2008.53.1.0339.

Flatté, S.M., R. Dashen, W. Munk, K. Watson, and F. Zachariasen. 1979. Sound

Transmission Through a Fluctuating Ocean. Cambridge University Press,

Cambridge, UK, 320 pp.

Garrett, C., and W. Munk. 1975. Space-time scales of internal waves: A progress

report. Journal of Geophysical Research 80(3):291–297, https://doi.org/10.1029/

JC080i003p00291.

Garrett, C., and E. Kunze. 2007. Internal tide generation in the deep ocean.

Annual Review of Fluid Mechanics 39(1):57–87, https://doi.org/10.1146/annurev.

fluid.39.050905.110227.

Garwood, J.C., R.C. Musgrave, and A.J. Lucas. 2020. Life in internal waves.

Oceanography 33(3):38–49, https://doi.org/10.5670/oceanog.2020.313.

Gill, A.E. 1982. Atmosphere-Ocean Dynamics. International Geophysics Series,

vol. 30, Academic Press, London, UK, 680 pp.

Goodfellow, I.J., J. Pouget-Abadie, M. Mirza, B. Xu, D. Warde-Farley,

S. Ozair, A. Courville, and Y. Bengio. 2014. Generative adversarial networks.

ArXiv:1406.2661 [Cs, Stat], https://doi.org/10.48550/arXiv.1406.2661.

Greer, A., R.K. Cowen, C.M. Guigand, J.A. Hare, and D. Tang. 2014. The role of inter­

nal waves in larval fish interactions with potential predators and prey. Progress in

Oceanography 127:47–61, https://doi.org/10.1016/j.pocean.2014.05.010.

Helber, R.W., C.N. Barron, M.R. Carnes, and R.A. Zingarelli. 2008. Evaluating the

sonic layer depth relative to the mixed layer depth. Journal of Geophysical

Research 113(C7), https://doi.org/10.1029/2007JC004595.

Hendershott, M.C. 1981. Long waves and ocean tides. Pp. 292–341 in Evolution of

Physical Oceanography. B. Warren and C. Wunsch, eds, MIT Press.

Hiron, L., M.C. Schönau, K.J. Raja, E.P. Chassignet, M.C. Buijsman, B.K. Arbic,

A. Bozec, E.F. Coelho, and M.S. Solano. 2025. The influence of vertical resolution

on internal tide energetics and subsequent effects on underwater acoustic prop­

agation. Journal of Advances in Modeling Earth Systems 17:e2024MS004389,

https://doi.org/10.1029/2024MS004389.

Hogan, T.F., M. Liu, J.A. Ridout, M.S. Peng, T.R. Whitcomb, B.C. Ruston,

C.A. Reynolds, S.D. Eckermann, J.R. Moskaitis, N.L. Baker, and others. 2014.

The Navy Global Environmental Model. Oceanography 27(3):116–125,

https://doi.org/​10.5670/oceanog.2014.73.

Lucas, A.J., P.J.S. Franks, and C.L. Dupont. 2011. Horizontal internal-tide fluxes

support elevated phytoplankton productivity over the inner continental

shelf. Limnology and Oceanography: Fluids and Environments 1(1):56–74,

https://doi.org/​10.1215/21573698-1258185.

Made with Publuu - flipbook maker