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Abstract Submesoscale coherent vortices (SCVs) are long‐lived subsurface‐intensified eddies that advect heat, salt, and biogeochemical tracers throughout the ocean. Previous observations indicate that SCVs are abundant in the Arctic because sea ice suppresses surface‐intensified mesoscale structures. Regional observational and modeling studies have indicated that SCVs may be similarly prevalent beneath Antarctic sea ice, but there has been no previous systematic attempt to observe these eddies. This study presents the discovery of eddies in the Southern Ocean's seasonally sea ice‐covered region using the Marine Mammals Exploring the Oceans Pole to Pole (MEOP) hydrographic measurements. Eddies are identified via a novel algorithm that utilizes anomalies in spice, isopycnal separation, and dynamic height along MEOP seal tracks. This algorithm is tested and calibrated by simulating the MEOP seal tracks using output from a 1/48 global ocean/sea ice model, in which subsurface eddies are independently identified via the Okubo–Weiss parameter. Approximately 60 detections of cyclonic and over 100 detections of anticyclonic SCVs are identified, with typical dynamic height anomalies of , core depths of , and vertical half‐widths of , similar to their Arctic counterparts. The eddies exhibit a pronounced geographical asymmetry: cyclones are exclusively observed in the open ocean, while 90% of the anticyclones are located on the continental shelf, consistent with injection of low‐potential vorticity waters by surface buoyancy loss. These findings provide a first observational characterization of eddies in the seasonally ice‐covered Southern Ocean, which will serve as a basis for future investigation of their role in near‐Antarctic circulation and tracer transport.
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This content will become publicly available on March 1, 2026
Observed Seasonality of Mixed‐Layer Eddies and Vertical Heat Transport Over the Antarctic Continental Shelf
Abstract The Antarctic continental shelf (ACS) hosts processes that impact the climate system globally, which has motivated ongoing efforts to characterize its state, circulation, and variability. However, the nature and consequences of eddies over the ACS, and their contributions to the budgets of heat and freshwater, remain systematically understudied. This study uses hydrographic measurements collected from instrumented seals, supported by a high‐resolution model of the southern Weddell Sea, to characterize eddies and their role in vertical heat transport around the entire ACS. A key finding is that eddies are ubiquitous, and exhibit frequent (2%–10% of hydrographic casts) occurrences of bulk Richardson numbers, indicative of submesoscale variability. However, along‐track density power spectra exhibit wavenumber dependences of , consistent with quasigeostrophic turbulence. Approximately of the points in the surface mixed layer satisfy conditions favorable for symmetric instability, although its prevalence is likely higher than this due to the relatively coarse resolution of the seal tracks. Vertical heat transports, estimated from a regional model‐calibrated parameterization of submesoscale restratification, are largest in shelf regions hosting dense water, which have previously been identified as key sites of warm water intrusions onto the ACS. These regions also exhibit the largest seasonal cycles, with elevated winter eddy activity and heat fluxes accompanying the formation of high salinity shelf waters. These findings indicate that eddies may contribute substantially to ACS heat and tracer budgets, and motivate further study of their role in determining the pathways and fate of heat that intrudes onto the ACS.
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- PAR ID:
- 10631932
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Oceans
- Volume:
- 130
- Issue:
- 3
- ISSN:
- 2169-9275
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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