Presenter: Alena Malyarenko (NIWA)

Description:
The Ross Sea freshening has been observed since the 1970s to early 2010s and has been attributed to increased melting of ice shelves in the Amundsen Sea, strengthening of melt-driven circulation and coastal current bringing the meltwater westward. Recently the salinification of High Salinity Shelf Water (HSSW) has been observed in the Ross Sea. Studies have shown that HSSW, formed in the Ross Sea polynya, flows into the Ross Ice Shelf cavity, and thus influences the Ross Ice Shelf melting. Supply of the HSSW in winter is associated with anticyclonic circulation and increased ocean velocities in the cavity. Thus changes in HSSW temperature and salinity, and the resulting ocean circulation, can modulate the cavity melt rates where HSSW is in contact with the ice shelf base. Here, we present results of the sea ice - ocean - ice shelf model (MITgcm) for the Ross Sea region. The model has 10km horizontal resolution. It has been forced with different ocean boundary conditions that include the Ross Sea freshening, while the atmosphere forcing has been kept constant with ERA5 climatology for the region. We show how local sea ice production, as well as boundary conditions, change the Ross Ice Shelf cavity circulation and melt rates.