Interannual Variations of Heat Budget over the Eastern Ross Sea Shelf and the Forcing Mechanisms

Abstract The temporal variation of heat budget in the subsurface layer of the eastern Ross Sea shelf (ERSS) is crucial for understanding the stability of ice shelves in the Ross Sea. In this study, six-year simulations from the Southern Ocean State Estimate (SOSE) are employed to analyze the interannual variations of heat budget in the subsurface layer of ERSS and the controlling mechanisms. The results reveal that the annual change in the heat content of the study region is dominated by the horizontal heat advection term, and only in one year the vertical advection and diffusion terms also play an important role. The horizontal advection term is co-affected by the intrusion of warm circumpolar deep water (CDW) onto the shelf across the northern boundary of ERSS, the transport of cold high salinity shelf water (HSSW) from the western Ross Sea shelf (WRSS), and the transport of CDW across the western boundary of ERSS. Contributions from these physical processes to the change of annual heat content vary over the years. The interannual variation of the CDW intrusion is modulated by the strength of eddy activities over the slope, and the interannual variation of heat transports related to HSSW is affected both by the extent of HSSW on the western shelf and coastal circulations that affect the eastward spreading of HSSW.