The Xiamen Symposium on Marine Environmental Sciences (XMAS 2025)

High-salinity shelf water (HSSW) acts as a precursor to Antarctic Bottom Water (AABW) and plays a critical role in regulating the global ocean circulation system. This study utilizes a high-resolution Ross Sea-Amundsen Sea ocean-sea ice-ice shelf model to analyze the variability in HSSW formation in the Ross Sea from 2003 to 2019, with a focus on the extreme HSSW event during the winter of 2007. The results indicate that during the winter of 2007, synoptic-scale cyclones were predominantly located near the front of the Ross Ice Shelf. Under the influence of local topography, the western flanks of these cyclones significantly enhanced offshore winds, leading to a sharp increase in ice production within the Ross Ice Shelf polynya, which directly contributed to the substantial HSSW formation. However, despite this increase in HSSW, the salinity and density of the Ross Sea decreased significantly during the same period. Further investigation revealed that this anomaly was due to a rapid increase in ice shelf melting in the Amundsen Sea and Ross Seas during 2006-2007, with annual cumulative melt rates reaching up to 600 Gt yr^^-1, the highest in recent decades. The resulting large inflow of meltwater was transported westward into the Ross Sea by a strong coastal current, leading to an increase in freshwater in the region. This increase in freshwater flux, combined with the increased production of HSSW, created a dynamic interplay that ultimately altered the hydrographic characteristics of the Ross Sea.