Multilevel Drifter-Based Analysis of a Coherent Submesoscale Eddy in the Balearic Sea.
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| Title: | Multilevel Drifter-Based Analysis of a Coherent Submesoscale Eddy in the Balearic Sea. |
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| Authors: | Dotzel, Michael M.1,2 (AUTHOR), Rypina, Irina I.1 (AUTHOR), Poulain, Pierre-Marie3 (AUTHOR), Pratt, Larry J.1 (AUTHOR), Ozgokmen, Tamay4 (AUTHOR), Centurioni, Luca5 (AUTHOR) |
| Source: | Journal of Physical Oceanography. Feb2026, Vol. 56 Issue 2, p481-509. 29p. |
| Subjects: | Vertical motion, Three-dimensional flow, Transport theory, Ocean |
| Abstract: | Submesoscale eddies are of significant importance for both horizontal and vertical transport of tracers in the ocean, but prior observations lack sufficient spatiotemporal coverage to characterize three-dimensional properties over the course of their lifetimes. This work represents the first set of observations of a submesoscale eddy resolving its continuous three-dimensional velocity structure, using shipboard profiling and taking advantage of 2 weeks of continuous data from a suite of multilevel drifters. As revealed by our analysis, this eddy, an unusually coherent ∼4-km radius elliptical cyclone persisting for nearly 1 month, is nearly depth independent in size and shape with vorticity ∼1.5f–2f and oscillating divergence of average magnitude ∼0.6f at drifter-resolved depths down to 50 m (here, f denotes the local Coriolis parameter). From the analysis of drifter data and underway profiling, the eddy exhibits no tendency toward instability and no appreciable change in size, but its swirl strength does gradually weaken from week 1 to week 2. There is evidence of strong upward and downward motion with vertical velocities up to 2 mm s−1. Since the majority of drifters are trapped within the eddy for 2 weeks, Lagrangian coherence metrics are able to be calculated, albeit intermittently due to patchy mapped velocity fields. In resolving three-dimensional geometric and limited coherence properties of this submesoscale eddy over these 2 weeks, this work aims to shed light on the three-dimensional profile of certain long-lived, coherent submesoscale eddies, which can contribute to long-term tracer entrainment and both lateral and vertical transport. Significance Statement: Submesoscale eddies are important for both horizontal and vertical transports in the ocean, but prior observations are unable to characterize three-dimensional properties of these eddies over their lifetimes. This work represents a particularly unique observation of a month-long-lived submesoscale eddy, tracked for 2 weeks using a large suite of floating buoys, or drifters, at different depths. This work also represents the first set of observations of a submesoscale eddy resolving its three-dimensional structure. A synthesis of drifter trajectory data and shipboard density and velocity measurements is able not only to characterize the geometry and the flow properties of the eddy at different depths but also to provide insight into its longevity as well as estimates of forces that might balance the eddy dynamics. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | Submesoscale eddies are of significant importance for both horizontal and vertical transport of tracers in the ocean, but prior observations lack sufficient spatiotemporal coverage to characterize three-dimensional properties over the course of their lifetimes. This work represents the first set of observations of a submesoscale eddy resolving its continuous three-dimensional velocity structure, using shipboard profiling and taking advantage of 2 weeks of continuous data from a suite of multilevel drifters. As revealed by our analysis, this eddy, an unusually coherent ∼4-km radius elliptical cyclone persisting for nearly 1 month, is nearly depth independent in size and shape with vorticity ∼1.5f–2f and oscillating divergence of average magnitude ∼0.6f at drifter-resolved depths down to 50 m (here, f denotes the local Coriolis parameter). From the analysis of drifter data and underway profiling, the eddy exhibits no tendency toward instability and no appreciable change in size, but its swirl strength does gradually weaken from week 1 to week 2. There is evidence of strong upward and downward motion with vertical velocities up to 2 mm s−1. Since the majority of drifters are trapped within the eddy for 2 weeks, Lagrangian coherence metrics are able to be calculated, albeit intermittently due to patchy mapped velocity fields. In resolving three-dimensional geometric and limited coherence properties of this submesoscale eddy over these 2 weeks, this work aims to shed light on the three-dimensional profile of certain long-lived, coherent submesoscale eddies, which can contribute to long-term tracer entrainment and both lateral and vertical transport. Significance Statement: Submesoscale eddies are important for both horizontal and vertical transports in the ocean, but prior observations are unable to characterize three-dimensional properties of these eddies over their lifetimes. This work represents a particularly unique observation of a month-long-lived submesoscale eddy, tracked for 2 weeks using a large suite of floating buoys, or drifters, at different depths. This work also represents the first set of observations of a submesoscale eddy resolving its three-dimensional structure. A synthesis of drifter trajectory data and shipboard density and velocity measurements is able not only to characterize the geometry and the flow properties of the eddy at different depths but also to provide insight into its longevity as well as estimates of forces that might balance the eddy dynamics. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 00223670 |
| DOI: | 10.1175/JPO-D-24-0075.1 |
