Model-based quantification of fluxes between shelf seas (Deliverable D1.8)

The Antarctic marginal seas are interconnected through generally westward flowing current systems such as the Antarctic Slope Current (ASC, Thompson et al. 2018 ) and the Antarctic Coastal Current (ACoC) along the continental slope and coast, respectively. The ASC is a quasi-circumpolar feature that starts in the Bellingshausen Sea and vanishes near the tip of the Antarctic Peninsula in the Weddell Sea, and is most pronounced along the East Antarctic continental slope downstream of the Ross Sea. The ASC transports various water masses, such as surface waters, Circumpolar Deep Water (CDW, >0°C), and newly formed Antarctic Bottom Water (AABW), and can thus impact hydrographic conditions and processes in neighboring subregions by advecting hydrographic anomalies. In this deliverable, we quantify fluxes between different Antarctic subregions and assess their downstream impact based on output from the Finite volumE Sea Ice-Ocean Model (FESOM2).We used FESOM2 to quantify the transport on the continental shelf and slope (Fig. 1) and find that the net exchange is much larger on the slope. The transport was split into three water masses, namely Surface Water (SW), Circumpolar Deep Water (CDW), and AABW. A more in-depth analysis was carried out for along-slope transports of AABW across boundaries between different Antarctic shelf seas.The model was able to reproduce the dominant source regions of AABW in the Weddell and Ross Seas, as well as the minor contributions from Prydz Bay and Cape Darnley (Cooperation Sea), and Adélie Coast (Dumont D’Urville Sea). Read more in the text of the deliverable. The model results used in this study are freely available from Zenodo, see the summary table below. Simulation Variables DOIs link Circumpolar Simulation Reference Run PT and S https://zenodo.org/records/15189061 Circumpolar Simulation Reference Run U and V https://zenodo.org/records/15280675 Bellingshausen and Amundsen Seas Experiment (BeAm) PT and S https://zenodo.org/records/15267996 BeAm experiment U and V https://zenodo.org/records/15299650 West and Shackleton Ice Shelf Experiment (WeSh) PT and S https://zenodo.org/records/15268272 WeSh experiment U and V https://zenodo.org/records/15299425 Eastern Weddell Sea Experiment (EWS) PT and S https://zenodo.org/records/15268317 EWS experiment U and V https://zenodo.org/records/15299705