This work aimed to understand the influences of tropical to high-latitude Southern Hemisphere teleconnections on Southern Ocean atmospheric circulation, the air-sea-sea ice system, and Antarctic sea ice variability. It also sought to investigate how the Southern Annular Mode (SAM) interacts with tropically-forced climate patterns such as Zonal Wave 3 (ZW3) to affect high-latitude atmospheric circulation and impact sea-ice.

The ocean absorbs >90% of anthropogenic heat in the Earth system, moderating global atmospheric warming. However, it remains unclear how this heat uptake is distributed by basin and across water masses. Here we analyze historical and recent observations to show that ocean heat uptake has accelerated dramatically since the 1990s, nearly doubling during 2010–2020 relative to 1990–2000. Of the total ocean heat uptake over the Argo era 2005–2020, about 89% can be found in global mode and intermediate water layers, spanning both hemispheres and both subtropical and subpolar mode waters. Due to anthropogenic warming, there are significant changes in the volume of these water-mass layers as they warm and freshen. After factoring out volumetric changes, the combined warming of these layers accounts for ~76% of global ocean warming. We further decompose these water-mass layers into regional water masses over the subtropical Pacific and Atlantic Oceans and in the Southern Ocean. This shows that regional mode and intermediate waters are responsible for a disproportionate fraction of total heat uptake compared to their volume, with important implications for understanding ongoing ocean warming, sea-level rise, and climate impacts. The study titled “Recent acceleration in global ocean heat accumulation by mode and intermediate waters” was published in Nature Communications in October 2023. All datasets are publicly accessible (https://doi.org/10.5281/zenodo.17274477) and are additionally linked to this record.

The Whole-Antarctic Ocean Model (WAOM) is based on the Regional Ocean Modelling System (ROMS) with thermodynamic ice shelf interactions following Galton-Fenzi et al. (2012)¹. WAOM simulations of the present-day (year 2007) were used to investigate the physical drivers of Antarctic ice shelf basal melting via an ocean heat budget in a longitudinal framework. Ice shelves buttress the Antarctic Ice Sheet and therefore are critical in the dynamics of ice sheet instability and its contribution to sea level rise. New insights into the seasonal melting mechanisms and its importance at circum-Antarctic scale were investigated in Dias et al (2025)². 1) Galton-Fenzi B, Hunter JR, Coleman R, Marsland SJ, & Warner RC. (2012) Modeling the basal melting and marine ice accretion of the Amery Ice Shelf, Journal of Geophysical Research: Oceans, 117 (C9). https://doi.org/10.1029/2012JC008214 2) Boeira Dias F, England MH, Morrison AK, & Galton-Fenzi B. (2025).: On the seasonal variability of ocean heat transport and ice shelf melt around Antarctica, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2024-3905