The Weddell Sea is a globally-relevant Antarctic region that features the largest ice shelf by volume (Filchner-Ronne Ice Shelf), year-round sea ice cover, and a wide continental shelf. The extensive sea ice formation creates dense near-freezing shelf waters, which effectively block out a large-scale presence of Circumpolar Deep Water and provide a considerable part of the Antarctic Bottom Water to the global ocean circulation. The German Alfred-Wegener-Institute (AWI) together with international partners focuses on observing the Weddell Sea with autonomous floats and oceanographic moorings, in order to study the circulation around the Weddell Gyre, and to understand the warm water inflow mechanisms toward the ice shelves as well as dense water formation and export pathways. In this presentation, we will present recent findings from the southern Weddell Sea based on oceanographic moorings on the continental shelf and from underneath Filchner Ice Shelf as well as from novel terrain-following under-ice Argo floats, complemented with results from high-resolution circumpolar ice shelf cavity-resolving model simulations. Finally, we will discuss plans for national and international Antarctic research programs and outline upcoming expeditions to the Weddell Sea.

The West Antarctic Ice Sheet holds the equivalent volume of ice to raise global sea levels by 5 m. While climate was only 1°C warmer than present, evidence suggests that the West Antarctic Ice Sheet may have collapsed completely during the Last Interglacial Period. With projections of global average temperatures reaching up to 5°C above pre-industrial by 2100 in the most extreme scenario, understanding the response of the ice sheet to changes in climate is vital for projecting future sea level rise. The New Zealand National Modelling Hub was established to bring together research fellows with modelling expertise in different disciplines to work on better understanding past, present and future Antarctic climate. Spanning ocean, atmosphere, ice sheets and earth system modelling; the team of research fellows and their students work alongside the New Zealand Antarctic Science community in providing model output to support the interpretation of paleoclimate proxies, to improve the representation of present day processes in models and to produce projections of future Antarctic climate change. In this seminar, ice sheet modeller Alanna Alevropoulos-Borrill from the New Zealand National Modelling Hub will give an overview of some of the recent and ongoing research projects within the group that contribute to the broad understanding of the stability of the West Antarctic ice sheet and its response to climate.