Oral or Poster

IACS

JCMP09 - Ice sheet mass loss: A driver of sea level rise

Delayed Impact of the Southern Annular Mode on Antarctic Fast Ice

Antarctic fast ice is crucial for the stability of ice shelves and the formation of Antarctic Bottom Water, influencing sea level rise. This study examines the influence of the Southern Annular Mode (SAM) on fast ice dynamics in March. The research indicates that the variability of circum-Antarctic fast ice in March is linked to the strength of the SAM from the previous September, particularly affecting Dronning Maud Land (DML) and the Amundsen Sea (AS). The relationship is driven by spring wind patterns influenced by the September SAM, leading to sea ice reduction. In DML and AS, a positive SAM phase results in northward sea ice drift near the coast, decreasing surrounding sea ice during spring. This reduction is exacerbated by increased net solar radiation due to lower albedo. Consequently, coastal ocean swells intensify during summer, significantly reducing fast ice in March. Additionally, the strength of the SAM-fast ice variability relationship appears to be modulated by the zonal asymmetry of SAM, which is intensifying due to global warming. Further research is needed to understand the impact of Antarctic atmospheric variability on sea ice and ice sheet stability.