Circum-Antarctic bottom water formation mediated by tides and topographic waves

The downslope plumes of dense shelf water (DSW) are critical for the formation of Antarctic Bottom Water (AABW), influencing heat and carbon exchange between the surface and abyssal ocean. This study synthesizes in situ observations and numerical model experiments to demonstrate that tides and topographic Rossby waves (TRWs) play comparable roles in AABW formation, accelerating DSW descent and creating colder, denser AABW. However, tides only significantly impact AABW formation on steep continental slopes where TRW generation is suppressed. The study characterizes dynamical regimes of dense overflows around Antarctica based on the relative importance of TRWs versus tides, highlighting the under-represented role of high-frequency processes in current climate models.

Xianxian Han, Andrew L. Stewart, Dake Chen, Markus Janout, Xiaohui Liu, Zhaomin Wang, Arnold L. Gordon