EGU21-15402
https://doi.org/10.5194/egusphere-egu21-15402
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Observations of vertical propagation of near-inertial Waves in a complex vorticity field during the EURAC4A-OA campaign in the tropical western North Atlantic

Daniel Rudloff1, Johannes Karstensen2, Tim Fischer2, Florian Schütte2, Arne Bendinger3, Sabrina Speich4, Pierre L'Hegaret4, Xavier Carton5, Gilles Reverdin5, Rémi Laxenaire4,6, and Jonathan Gula5
Daniel Rudloff et al.
  • 1Kiel University, Kiel, Germany
  • 2GEOMAR, Helmholtz Zentrum für Ozeanforschung Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
  • 3LEGOS (Laboratoire d’Etudes en Géophysique et Océanographie Spatiales), Université de Toulouse, IRD, CNES, CNRS, UPS, Toulouse, France
  • 4Laboratoire de Météorologie Dynamique, UMR 8539 École Polytechnique, ENS, CNRS, Paris, France
  • 5Université de Bretagne Occidentale, Laboratoire d'Océanographie Physique et Spatiale, Brest, France
  • 6Center for Ocean‐Atmospheric Prediction Studies, Florida State University, Tallahassee, FL, USA

In this study, we investigate the mesoscale flow field and how it enables energy to propagate vertically in form of near-inertial waves. As part of the EURAC4A-OA campaign the research vessels RV Maria S. Merian and NO L’Atalante simultaneously surveyed mesoscale eddy fronts in the western tropical North Atlantic. From velocity profile data, measured by a shipboard Acoustic Doppler Current Profiler (sADCP), we reconstruct eddies in the upper 1000m of the surveyed area, by fitting a Rankine Vortex model. The model derives an idealized velocity structure of the eddy as well as the location of its centre. Multiple occurrences of stacked eddies are identified and often surrounded by current shear structures associated with near-inertial waves. Using data from ship sections, where both research vessels operated less than 1nm apart, the vertical component of the relative vorticity (zeta) is calculated using different methods (single ship, two ships)[Shcherbina et al. 2013]. It is found that in particular zeta outside of the eddy cores is sensitive to the way the vorticity is calculated and may even change sign. Furthermore, the resulting zeta sections and its impact on the ability of near-inertial waves propagating vertically below the mixed layer is discussed.

How to cite: Rudloff, D., Karstensen, J., Fischer, T., Schütte, F., Bendinger, A., Speich, S., L'Hegaret, P., Carton, X., Reverdin, G., Laxenaire, R., and Gula, J.: Observations of vertical propagation of near-inertial Waves in a complex vorticity field during the EURAC4A-OA campaign in the tropical western North Atlantic, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15402, https://doi.org/10.5194/egusphere-egu21-15402, 2021.

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