Archive | 2021
Water masses distribution offshore the Sabrina Coast (East Antarctica)
Abstract
9 Current glacier melt rates in West Antarctica substantially exceed those around the East Antarctic margin. The exception is Wilkes 10 Land where, e.g., Totten Glacier, underwent significant retreat between 2000 and 2012, underlining its sensitivity to climate 11 change. This process is strongly influenced by ocean dynamics, which in turn changes in accordance with the evolution of the ice 12 caps. Here, we present oceanographic data (temperature, salinity, density, dissolved oxygen) collected for the first time offshore 13 the Sabrina Coast (East Antarctica), from the continental shelf break to ca 3000 m depth during austral summer 2017. 14 The main water masses are identified by analysing thermohaline properties: the Antarctic Surface Water with θ > -1. 5 °C and S 15 < 34.2 (σθ < 27. 55 kg m-3), the Winter Water with -1.92 < θ < -1.75 °C and 34.0 < S < 34.5 (27.55 < σθ < 27.7 kg m-3), the 16 modified Circumpolar Deep Water with θ > 0 °C and S > 34.5 (σθ > 27.7 kg m-3), and Antarctic Bottom Water with -0.50 < θ < 0 17 °C and 34.63 < S < 34.67 (27.83 < σθ < 27.85). The latter in this region is a mixture of dense waters originating from the Ross Sea 18 and Adélie Land continental shelves, and is affected by the mixing process they undergo as they move westward along the Antarctic 19 margin and interact with the locally formed dense waters, and with the warmer and saltier Circumpolar Deep Water. 20 The spatial distribution of water masses offshore the Sabrina Coast also appears to be strongly linked with the complex morpho21 bathymetry of the slope and rise area, supporting the hypothesis that downslope processes contribute to shaping the architecture 22 of the distal portion of the continental margin. 23 Short summary (plain text) 24 The Totten Glacier (Sabrina Coast, East Antarctica) has undergone significant retreat in recent years, underlining its sensitivity to 25 climate change and its potential contribution to global sea-level rise. The melting process is strongly influenced by ocean dynamics 26 and the spatial distribution of water masses appears to be linked to the complex morpho-bathymetry of the area, supporting the 27 hypothesis that downwelling processes contribute to shaping the architecture of the continental margin. 28 https://doi.org/10.5194/essd-2021-245 O pe n A cc es s Earth System Science Data D icu ssio n s Preprint. Discussion started: 26 July 2021 c © Author(s) 2021. CC BY 4.0 License.