Southern Ocean and West Antarctic continental shelf biases and future projections in Global Climate Models

Lekakou, Kyriaki M. (2023) Southern Ocean and West Antarctic continental shelf biases and future projections in Global Climate Models. Doctoral thesis, University of East Anglia.

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Abstract

The proximity of the Antarctic Circumpolar Current to the West Antarctic continental shelf allows for warm water to intrude onto it, reach the base of the ice shelves and cause basal melt. Persistent biases in the Southern Ocean sea ice, circulation, temperature and salinity create uncertainty in our future projections of subsurface temperature on the West Antarctic continental shelf. The ability of climate models to represent Southern Ocean features realistically is crucial for increasing confidence in our future projections.

We assess 4 CMIP6 climate models with different horizontal resolution, from 1° to 1/12°, and found large differences in their ability to represent Southern Ocean characteristics. The 1/4° model has large sea ice, circulation, temperature and salinity biases and a fresh and cold West Antarctic continental shelf with a westward slope current. A link between high sea ice melt rates in West Antarctica and subsurface freshening on the West Antarctic continental shelf is found. The best performing model in our study is the 1/12° resolution model with minimal biases in the Southern Ocean. Future projections of subsurface temperature in the Amundsen Sea in the 1/12° model demonstrate deep cooling by 2050. On the other hand, future projections of the 1/4° model exhibit deep warming in the Amundsen Sea by the end of the century, similar to the 1° models.

Horizontal resolution plays an important role in representing circulation features, such as the slope current. Its presence is linked with changes in subsurface temperature and salinity on the West Antarctic continental shelf. It is possible that the West Antarctic continental shelf can shift from a warm state to a cold one and vice versa. Investigating the mechanisms behind these shifts is critical for future projections of subsurface temperature and ice shelf melt rates.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Environmental Sciences
Depositing User:	Chris White
Date Deposited:	21 Oct 2024 10:22
Last Modified:	21 Oct 2024 10:22
URI:	https://ueaeprints.uea.ac.uk/id/eprint/97074
DOI:

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