Abstract

Antarctic Bottom Water (AABW) is an important part of the climate system as it occupies about one-third of the ocean’s volume, ventilates the abyss, and stores heat and carbon for centuries. The formation of AABW at the Antarctic continental margin is therefore a key process in the global ocean circulation but observing and accurately modelling AABW remains an ongoing challenge. The aim of my PhD thesis has been to deepen our understanding of AABW dynamics, motivated by its critical role in the global ocean and declining AABW volume in a warming climate. Using ocean–sea ice models, I investigate the interannual variability of AABW formation and its underlying drivers. I then examine the response of salinity in the Ross Sea to wind and meltwater variability to advance our understanding of the physical mechanisms behind the recent salinity rebound in the Ross Sea. Finally, I assess the horizontal model resolution required to accurately simulate AABW formation. By improving our understanding of past AABW variability and identifying the model resolution required to simulate AABW , this work contributes to more reliable future projections of AABW formation and the evolution of the global overturning circulation.