How the complexity of continental breakup controls Southern Ocean circulation ...

• Main Author: Xing, Qianjiang
• Format: Thesis
• Language: unknown
• Published: University of Tasmania 2024
• Subjects: Antarc*; Antarctic; Southern Ocean
• Online Access: https://dx.doi.org/10.25959/26027107; https://figshare.utas.edu.au/articles/thesis/How_the_complexity_of_continental_breakup_controls_Southern_Ocean_circulation/26027107

Around 30 million years ago, the globe underwent a climate transition from “greenhouse” to “icehouse” conditions, usually termed the Eocene-Oligocene transition (EOT). Co?evally, Southern Ocean horizontal circulation changed from a two-gyre pattern with a weak proto-Antarctic Circumpolar Current (ACC) to a more modern regime of ACC dominance. In addition, the meridional overturning circulation (MOC) shifted from a bipolar mode of the early MOC in the Pacific to the modern Atlantic MOC, associated with the tectonically driven opening of Southern Ocean gateways. In an Earth system, ACC and MOC are coupled together through their dependencies on the stratification. But they are not driven by each other. The mechanisms driving the changes in Southern Ocean horizontal circulation through the EOT have been investigated for decades. Two main factors are emphasised in the paleoceanography community; the opening of ocean gateways and wind stress adjust?ments. However, previous studies show that neither deepening of ...