Temporal variability of meltwater in front of Dotson Ice Shelf

• Main Authors: Zheng, Y., Hall, R., Heywood, K., Queste, B., Sheehan, P., Damerell, G.
• Format: Conference Object
• Language: English
• Published: 2023
• Subjects: Amundsen Sea; Dotson Ice Shelf; Ice Shelf; Ice Shelves
• Online Access: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018441

Ice shelves terminating towards the Amundsen Sea are losing mass rapidly, exporting an increasing amount of meltwater into the ocean. Investigation into the fate of the glacial meltwater in the Amundsen Sea is therefore pressing for predicting the future climate response to the ice shelf processes. However, observations near ice shelves often lack continuity in either time or space, limiting our knowledge of the meltwater pathway. In summer 2022, we deployed six ocean gliders in front of the Dotson Ice Shelf (DIS), obtaining two ship CTD transects and 573 glider profiles, yielding more than ten fine-resolution (median horizontal sampling interval: 650 m) glider transects along the DIS within three weeks, allowing us to compare the full picture along DIS over short time scales (median sampling interval: 4.5 days). Glider transects reveal that the meltwater content is higher (about 20 g/kg) in the west (outflow) and lower in the east (inflow), with a meltwater-poor layer centred at about 350 m sandwiched by two meltwater-rich layers (above about 250 m and centred at about 450 m). We find particularly meltwater-poor cores within the meltwater-poor layer, potentially indicating eddies. Isopycnals diverge near the meltwater outflow core and shoal below about 600 m at the inflow region, indicating geostrophic flow out of and into the cavity respectively. We calculate the volume transport of meltwater exported from the ice shelf cavity and assess its variability during the three weeks.