The End of the Ocean Trip: Concluding Our Near-Inertial Waves and Mesoscale Eddies Study

25 May 2024


(1) Scott Conn, California Institute of Technology, Pasadena, California;

(2) Joseph Fitzgerald, California Institute of Technology, Pasadena, California;

(3) Jorn Callies, California Institute of Technology, Pasadena, California.

Abstract and Intro










6. Conclusion

The evolution of the NIW field at the OSMOSIS site in the Northeast Atlantic Ocean is strongly modulated by mesoscale eddies. The observed evolution can be captured by the YBJ model, which includes NIW refraction, advection, and dispersion. If these processes are omitted as in the PM model, the observations cannot be reproduced as well, even if the parameterized damping rate is tuned.

The YBJ model provides a powerful interpretive framework for understanding observations of NIWs in the upper ocean. It allows us to attribute the observed evolution to specific physical processes. Lateral differences in the NIW amplitude across the mooring array are caused by 𝜁-refraction, which causes NIW kinetic energy to be fluxed into anticyclonic regions.

While correlations between NIW amplitudes and mesoscale vorticity can be diagnosed from the observations alone (e.g., Yu et al. 2022), the YBJ framework produces a quantitative prediction for the NIW amplitudes that matches observations and provides a physical interpretation.

The YBJ model also allows us to calculate changes in the NIW potential energy, which are expected to arise from transfers of balanced mesoscale energy (Xie and Vanneste 2015; Rocha et al. 2018). For the strongest NIW event observed during the OSMOSIS campaign, the NIW potential energy gain is at least two orders of magnitude smaller than the global average energy input into mesoscale kinetic energy. Stimulated generation therefore does not appear to have a major impact on the mesoscale eddy field in this part of the ocean.

Acknowledgments. The authors thank two anonymous reviewers whose comments helped improve the presentation of this work. This material is based upon work supported by the National Science Foundation under Grant No. OCE-1924354 and by the National Aeronautics and Space Administration under Grant No. 80NSSC22K1445 issued through the Science Mission Directorate (Future Investigators in NASA Earth and Space Science and Technology).

Data availability statement. The code to run the 3D YBJ model is available at https: // All of the OSMOSIS data used as part of this study is available from the British Oceanographic Data Centre. The OSMOSIS mooring data is available at collection/6093/. The OSMOSIS glider data is available at 6cf0b33e-a192-549f-e053-6c86abc01204. The SSH data is available from the E.U.’s Copernicus Marine Service at The ERA5 reanalysis data is available from the Copernicus Climate Change Service (C3S) Climate Data Store at https: //

This paper is available on arxiv under CC 4.0 license.