Seasonal variability of SST fronts in the southern ocean south of 60°S: the relationship with sea ice

Abstract The role of sea ice in influencing the seasonal variability of sea surface temperature (SST) fronts in the Southern Ocean (SO) remains poorly understood. This study addresses this gap by utilizing Optimum Interpolation SST data and the Cayula and Cornillon algorithm to detect SST fronts. The findings demonstrate that, influenced by the seasonal expansion and contraction of sea ice, frontal activity south of 60°S varies significantly by season, peaking in summer and reaching its lowest in winter. Frontal frequency is notably higher in regions where sea ice concentration (SIC) falls below 0.2 but decreases when SIC exceeds this threshold, reflecting the impact of sea ice-driven changes in SST gradients on front formation. Additionally, the study reveals a distinct meridional pattern emerges in the distribution of SO fronts, with weaker activity south of 60°S and more intense activity in the Westerlies and further north. These results enhance our understanding of the interactions between sea ice and SST fronts, providing critical insights into the potential impacts of climate change on SO frontal systems.