Influence of the future surface meltwater from the Antarctic ice sheet on the Southern Ocean properties and ice-shelf basal melt

The Antarctic ice sheet mass loss is one of the many consequences of Global Warming. This mass loss is primarily driven by ocean warming and the subsequent acceleration of glaciers. The associated increase in iceberg and ice-shelf melt has been shown to significantly impact the Southern Ocean and the global climate. While sub-ice shelf cavities and subsequent basal melting are not represented in the models of the 5th phase of the Coupled Model Intercomparison Project (CMIP5), neither in the models of the phase 6 (CMIP6), some studies have highlighted the importance of this largest freshwater flux. It can significantly influence ocean properties and even potentially slow down the decline of the sea ice around Antarctica. Furthermore, it could also reduce mixing between surface water and warm Circumpolar Deep Waters, thereby increasingice shelf basal melt. The existing studies neglect the contribution of the surface meltwater notably because it is considered to be negligible over the present period and could remain low in the CMIP5-based projections to 2100. However, the most recent projections based on CMIP6 suggest surface melt rates at least as high as current basal melt rates, questioning the future influence of the surface meltwater on the ocean. We use the ocean and sea-ice model NEMO-SI3 to perform a simulation where future meltwater fluxes are added into the nearest ocean grid cells in addition to iceberg and ice-shelf melt. The comparison with a reference simulation will enable to study the sensitivity of the ocean properties and ice shelf basal melt to this additional freshwater flux, and also to assess the interest of taking into account this process in projections to 2100 and beyond.
info:eu-repo/semantics/published