Interpreting Observed Interactions between Near-Inertial Waves and Mesoscale Eddies

Creators: Conn, Scott¹; Fitzgerald, Joseph¹; Callies, Jörn¹

1. California Institute of Technology

Abstract

The evolution of wind-generated near-inertial waves (NIWs) is known to be influenced by the mesoscale eddy field, yet it remains a challenge to disentangle the effects of this interaction in observations. Here, the model of Young and Ben Jelloul (YBJ), which describes NIW evolution in the presence of slowly evolving mesoscale eddies, is compared to observations from a mooring array in the northeast Atlantic Ocean. The model captures the evolution of both the observed NIW amplitude and phase much more accurately than a slab mixed layer model. The YBJ model allows for the identification of specific physical processes that drive the observed evolution. It reveals that differences in the NIW amplitude across the mooring array are caused by the refractive concentration of NIWs into anticyclones. Advection and wave dispersion also make important contributions to the observed wave evolution. Stimulated generation, a process by which mesoscale kinetic energy acts as a source of NIW potential energy, is estimated to be 20 μW m−² in the region of the mooring array, which is two orders of magnitude smaller than the global average input to mesoscale kinetic energy and likely not an important contribution to the mesoscale kinetic energy budget in this region. Overall, the results show that the YBJ model is a quantitatively useful tool to interpret observations of NIWs.

Copyright and License (English)

© 2024 American Meteorological Society. This published article is licensed under the terms of the default AMS reuse license. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Acknowledgement (English)

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 OCE-1924354 and by the National Aeronautics and Space Administration under Grant 80NSSC22K1445 issued through the Science Mission Directorate (Future Investigators in NASA Earth and Space Science and Technology).

Funding (English)

This material is based upon work supported by the National Science Foundation under Grant OCE-1924354 and by the National Aeronautics and Space Administration under Grant 80NSSC22K1445 issued through the Science Mission Directorate (Future Investigators in NASA Earth and Space Science and Technology).

Data Availability (English)

All of the OSMOSIS data used as part of this study are available from the British Oceanographic Data Centre. The OSMOSIS mooring data are available at https://www.bodc.ac.uk/data/bodc_database/nodb/data_collection/6093/. The OSMOSIS glider data are available at https://doi.org/10.5285/6cf0b33e-a192-549f-e053-6c86abc01204. The SSH data are available from the E.U.’s Copernicus Marine Service at https://doi.org/10.48670/moi-00148. The ERA5 reanalysis data are available from the Copernicus Climate Change Service (C3S) Climate Data Store at https://doi.org/0.24381/cds.adbb2d47.

Code Availability (English)

The code to run the 3D YBJ model is available at https://github.com/scott-conn/3DYBJ.

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