Mixing in the Southern Ocean around Antarctica is one of the fundamental processes that influences the whole planet. This blending of waters redistributes ocean heat, which impacts on ice loss from Antarctica and global sea level rise; it also governs ocean productivity via supplying nutrients to the sunlit zone of the ocean, with consequences for ecosystems, carbon drawdown, and global climate. The causes and magnitudes of Southern Ocean mixing have been the subject of many major research programs, though critical gaps remain in our understanding and ability to represent this mixing in models.
This paper challenged the conventional wisdom that mixing close to Antarctica is driven by winds, tides and buoyancy forcing, and used unique measurements and modelling to demonstrate that the impact of calving icebergs is at least as important as these processes. The paper also argued that this process is strongly relevant in other places where marine-terminating glaciers are widespread, including Greenland, the Arctic, Patagonia and Alaska. There is a strong climatic dependency of this process, since the marine-terminating glaciers are retreating rapidly across many of these places, and are likely to continue to do so in the coming decades, thus impacting calving rates and mixing.
The findings in this paper were of great interest throughout the Earth science community, as well as policymakers, intergovernmental agencies and members of the public concerned with climate and our changing planet. The paper also presented remarkable measurements which we were very lucky to capture, with high-quality oceanographic measurements obtained from a major research vessel in direct proximity of a marine-terminating glacier during a significant calving event. We were lucky enough to spot the ship in front of the calving front at the time it was sampling in a Sentinel-1 SAR image acquired at the time.
Michael P. Meredith et al.,Internal tsunamigenesis and ocean mixing driven by glacier calving in Antarctica.Sci. Adv.8,eadd0720(2022).DOI:10.1126/sciadv.add0720