High Salinity Shelf Water production rates in Terra Nova Bay, Ross Sea from high-resolution salinity observations
Una Kim Miller, Christopher J. Zappa, Arnold L. Gordon, Seung‐Tae Yoon, Craig Stevens, Won Sang Lee
Abstract
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 (10 6 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 $$0.1$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mn>0.1</mml:mn> </mml:math> $${Sv}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>S</mml:mi> <mml:mi>v</mml:mi> </mml:math> , 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.