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 natureand consequences of eddies over the ACS, and their contributions to the budgets of heat and freshwater, remainsystematically 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 invertical heat transport around the entire ACS. A key finding is that eddies are ubiquitous, and exhibit frequent (2%–10% of hydrographic casts) occurrences of O(1) bulk Richardson numbers, indicative of submesoscalevariability. However, along‐track density power spectra exhibit wavenumber dependences of ~k^-3, consistentwith quasigeostrophic turbulence. Approximately 0.3% of the points in the surface mixed layer satisfyconditions favorable for symmetric instability, although its prevalence is likely higher than this due to therelatively 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 alsoexhibit the largest seasonal cycles, with elevated winter eddy activity and heat fluxes accompanying theformation of high salinity shelf waters. These findings indicate that eddies may contribute substantially to ACSheat and tracer budgets, and motivate further study of their role in determining the pathways and fate of heat thatintrudes onto the ACS.

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