The Dynamical Structure of a Warm Core Ring as Inferred from Glider Observations and Along-Track Altimetry
Abstract
:1. Introduction
2. Data
2.1. The Glider Survey
2.2. Satellite Altimetry
3. Methods
3.1. The Relocation Method
3.2. Validation
3.3. Theoretical Framework
4. Results
4.1. Thermohaline Structure
4.2. Velocity
4.3. Relative Vorticity and Strain
4.4. Potential Vorticity Structure
4.5. Energetics
5. Discussion
5.1. The Relocation Method
5.2. The LCR’s Vertical Structure
6. Summary
- A new altimetry-based method to relocate gliders observations in a synoptic frame of reference was designed and applied to recent observations of a Loop Current ring in the Gulf of Mexico.
- The method was tested using an analytical anticyclonic eddy drifting on the -plane, and shown to recover the exact vertical structure of the eddy, whatever the sampling strategy, in the ideal case of a stable and circular eddy.
- The method was successful in correcting the errors in horizontal thermohaline gradients, related to the lack of synopticity of glider surveys.
- The relocation method also allows to precisely locate the eddy’s rotation axis, yielding more reliable estimates of cyclo-geostrophic velocity, relative vorticity, and shear strain.
- The warm core ring consisted of a bowl of homogeneous negative relative vorticity, surrounded by a crown of positive shear strain, resulting in a negative Okubo–Weiss parameter in the core and positive at the periphery.
- The PV structure of the warm-core ring is largely dominated by vortex stretching.
- The along-isopycnal radial PV gradient is also dominated by gradients of the vortex stretching term.
- Sign-changes of the PV-gradient suggests that the warm core ring might be baroclinically unstable.
- The energy density partition revealed a clear dominance of available potential energy over kinetic energy.
- Available potential energy density is mostly contained within the vorticity-dominated core of the warm-core ring (negative Okubo–Weiss), where properties are expected to be well conserved. This might possibly contribute to its longevity.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Meunier, T.; Pallás Sanz, E.; de Marez, C.; Pérez, J.; Tenreiro, M.; Ruiz Angulo, A.; Bower, A. The Dynamical Structure of a Warm Core Ring as Inferred from Glider Observations and Along-Track Altimetry. Remote Sens. 2021, 13, 2456. https://doi.org/10.3390/rs13132456
Meunier T, Pallás Sanz E, de Marez C, Pérez J, Tenreiro M, Ruiz Angulo A, Bower A. The Dynamical Structure of a Warm Core Ring as Inferred from Glider Observations and Along-Track Altimetry. Remote Sensing. 2021; 13(13):2456. https://doi.org/10.3390/rs13132456
Chicago/Turabian StyleMeunier, Thomas, Enric Pallás Sanz, Charly de Marez, Juan Pérez, Miguel Tenreiro, Angel Ruiz Angulo, and Amy Bower. 2021. "The Dynamical Structure of a Warm Core Ring as Inferred from Glider Observations and Along-Track Altimetry" Remote Sensing 13, no. 13: 2456. https://doi.org/10.3390/rs13132456