We use five different versions of a biogeochemical model to show that how phytoplankton growth processes are represented strongly shapes projections of future ocean productivity and carbon export. Added model complexity does not have a uniform global effect as some new processes mainly influence specific ocean regions, while others, such as an additional small phytoplankton type, lead to large intramodel differences in future trends and latitudinal patterns of productivity and carbon export.

This study developed a kilometre-scale sea-ice model in OpenFOAM that couples dynamic and thermodynamic processes for two types of ice, solid-like ice floes and fluid-like grease ice, under wave forcing. This model can help to improve data input for large-scale sea-ice models. Results show a linear relationship between the proportion of ice floes in the field and the overall viscosity. Additionally, we found that viscosity responds nonlinearly to the inclusion of thermodynamic sea-ice growth.

Synoptic events have a significant influence on the evolution of Antarctic sea ice. Our current understanding of the interactions between cyclones and sea ice remains limited. Using two ensembles of buoys, deployed in the north-eastern Weddell Sea region during winter and spring of 2019, we show how the evolution and spatial pattern of sea ice drift and deformation in the Antarctic marginal ice zone were affected by the balance between atmospheric and oceanic forcing and the local ice.

The marginal ice zone (MIZ) in the Antarctic is the largest in the world ocean. Antarctic sea ice has large year-to-year changes, and the MIZ represents its most variable component. Processes typical of the MIZ have also been observed in fully ice-covered ocean and are not captured by existing diagnostics. A new statistical method has been shown to address previous limitations in assessing the seasonal cycle of MIZ extent and to provide a probability map of sea ice state in the Southern Ocean.

Based on observing system simulation experiments using a mesoscale-resolving model, we found that to significantly improve uncertainties and biases in carbon dioxide (CO₂) mapping in the Southern Ocean, it is essential to resolve the seasonal cycle (SC) of the meridional gradient of CO₂ through high frequency (at least daily) observations that also span the region's meridional axis. We also showed that the estimated SC anomaly and mean annual CO₂ are highly sensitive to seasonal sampling biases.