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Abstract High Salinity Shelf Water (HSSW) formed in the Ross Sea of Antarctica is a precursor to Antarctic Bottom Water (AABW), a water mass that constitutes the bottom limb of the global overturning circulation. HSSW production rates are poorly constrained, as in-situ observations are scarce. Here, we present high-vertical-and-temporal-resolution salinity time series collected in austral winter 2017 from a mooring in Terra Nova Bay (TNB), one of two major sites of HSSW production in the Ross Sea. We calculate an annual-average HSSW production rate of ~0.4 Sv (106 m 3 s −1), which we use to ground truth additional estimates across 2012–2021 made from parametrized net surface heat fluxes. We find sub-seasonal and interannual variability on the order of $$0.1$$ 0.1 $${Sv}$$ S v , with a strong dependence on variability in open-water area that suggests a sensitivity of TNB HSSW production rates to changes in the local wind regime and offshore sea ice pack.

At the calving front of Nansen Ice Shelf, Antarctica a 10-km wide eddy dominated the local circulation in austral summer 2018/19 and led to substantial vertical heat transport, according to rare observations with an autonomous glider and microstructure turbulence measurements.

Glacial melt can modify heat transport, and therefore ocean processes, associated with ice front retreat, as revealed by direct observations from the Pine Island Bay region of Antarctica.