The role of tides in bottom water export from the western Ross Sea
April 15,2021

Melissa M. Bowen, Denise Fernandez, Aitana Forcen-Vazquez, Arnold L. Gordon, Bruce Huber, Pasquale Castagno & Pierpaolo Falco

Published in Scientific Reports, JAN 2021

Approximately 25% of Antarctic Bottom Water has its origin as dense water exiting the western Ross Sea, but little is known about what controls the release of dense water plumes from the Drygalski Trough. We deployed two moorings on the slope to investigate the water properties of the bottom water exiting the region at Cape Adare. Salinity of the bottom water has increased in 2018 from the previous measurements in 2008–2010, consistent with the observed salinity increase in the Ross Sea. We find High Salinity Shelf Water from the Drygalski Trough contributes to two pulses of dense water at Cape Adare. The timing and magnitude of the pulses is largely explained by an inverse relationship with the tidal velocity in the Ross Sea. We suggest that the diurnal and low frequency tides in the western Ross Sea may control the magnitude and timing of the dense water outflow.

FIG.1 The study site is located on the western side of the Ross Sea (area of regional map shown in red on the upper map). Moorings P2 and P3 were located on the 1750 m isobath off Cape Adare and near the Drygalski Trough respectively (left panel; pink diamonds). The P2 mooring was deployed at the same location as the CA-1 mooring in the CALM experiment. The M3, M4 and M5 moorings were located near the Drygalski Trough during the AnSlope experiment (yellow diamonds). Mooring G in the Drygalski Trough is part of the MORSea Program (blue diamond). Contours are at 500 m, 1000 m, and 1750 m depth. Hydrographic sections were taken in 2018 along three lines perpendicular to the slope (light blue dots). Potential temperatures from the three sections are shown in the panels on the right, with the positions of the P2 and P3 moorings indicated.
(Maps produced in Matlab R2015a

Bowen, M.M., Fernandez, D., Forcen-Vazquez, A. et al. The role of tides in bottom water export from the western Ross Sea. Sci Rep 11, 2246 (2021).

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