The Response of Ross Sea Shelf Water Properties to Enhanced Amundsen Sea Ice Shelf Melting

Ice shelves in the Amundsen Sea have experienced the most rapid melting in the Antarctic and are expected to accelerate throughout this century under climate warming. In this study, a high-resolution ocean-sea ice-ice shelf model is employed to conduct sensitivity experiments to explore the effects of increasing melt rates of the Amundsen Sea ice shelves on hydrography, sea ice and ice shelf in the Ross Sea. The results indicate that the substantial inflow of meltwater significantly freshens the Ross Sea, inhibiting the formation and export of the Dense Shelf Water, the volume of which is reduced by 19%-33% on the shelf. Temperatures in the eastern and western Ross Sea exhibit different responses to the enhanced meltwater input. The freshening of the western Ross Sea weakens the mesoscale eddy activities which are efficient in carrying warm Circumpolar Deep Water onto the shelf, leading to an average temperature decrease of 0.02-0.08 degrees C. Conversely, in the eastern Ross Sea, there is a marked warming outside the shelf under increased meltwater, which results from zonal pressure gradients associated with the meltwater distributions. This consequently causes stronger on-shelf heat transport and shows warming of 0.12-0.22 degrees C on the eastern Ross Sea shelf. The narrow shelf in the eastern Ross Sea allows the warmer water to reach the Ross Ice Shelf (RIS) front, resulting in an about 6%-9% increase in the RIS melting. These results suggest a possible mechanism for acceleration in the RIS melting in the future that is associated with enhanced meltwater inflow. Many studies suggest that the Amundsen Sea ice shelf will experience accelerated melting throughout this century, leading to the release of a substantial amount of freshwater, which will be transported westward and impact the Ross Sea downstream. In this study, a numerical model including ocean, ice shelves and sea ice is used to simulate the effects of increased melting rates of the Amundsen Sea ice shelves on the Ross Sea ocean and ice environments. The results indicate pronounced differences in temperature changes in the eastern and western Ross Sea under enhanced meltwater input. The freshening of the western Ross Sea weakens the warm water intrude onto the shelf, resulting in cooling of the western Ross Sea. In the eastern Ross Sea, there is warming associated with changes in large-scale flows caused by the distributions of meltwater. More heat transport into the eastern Ross Sea shelf can reach the front of the Ross Ice Shelf (RIS) - the largest Antarctic ice shelf and promotes its melting. Our study proposes a mechanism for acceleration in the RIS melting in the future, highlighting the role of meltwater from the Amundsen Sea ice shelves. Enhanced Amundsen Sea ice shelf melting causes marked freshening of the Ross Sea and inhibits the formation of Antarctic Bottom Water The increased meltwater inflow from the Amundsen Sea causes cooling of the western Ross Sea and warming of the eastern Ross Sea More heat transport into the eastern Ross Sea shelf can reach the front of the Ross Ice Shelf and increase its melting rate