416 / 2024-09-16 17:39:10

Interannual Salinity Variability on the Ross Sea Continental Shelf in a regional Ocean-Sea Ice-Ice Shelf Model

Ross Sea,Salinity,Coupled model

In this study, we examine the processes that control interannual salinity variability on the Ross Sea continental shelf in a high-resolution regional coupled ocean-sea ice-ice shelf model. We show that both brine rejection and salt advection jointly dictate the interannual salinity variability. The surface salinization (freshening) can be caused by enhanced (reduced) sea ice production and reduced (enhanced) import of the upper layer water across the shelf break. When the vertical salt gradient is weak (strong), it is relatively easy (hard) to increase the salinity of HSSW by brine rejection. The east-west sea level pressure gradient across the Ross Sea significantly shapes the surface wind patterns over the Ross Sea continental shelf and hence controls sea ice export across the continental shelf break. Increased (reduced) sea ice export leads to enhanced (reduced) sea ice production as a result of reduced sea ice concentration and thickness on the Ross Sea continental shelf. Once the HSSW production is enhanced (reduced), the export of the lower layer saltier water and the import of the upper layer fresher water across the shelf break tends to increase (decrease), acting to make stronger (weaker) stratification and hence suppress the interannual salinity variability in the HSSW. This study offers a more comprehensive analysis of the mechanisms driving interannual salinity variability on the Ross Sea continental shelf, shedding light on understanding the complex coupled processes in this region and enhancing the broader understanding of polar oceanography and its response to climate change.