Increases in both ocean-driven melting of Antarctica’s floating ice shelves and iceberg calving into the ocean are the two main causes of mass loss from the Antarctic Ice Sheet. However, accurate knowledge of the ocean conditions around Antarctica and their future evolution remains largely uncertain.
There is an urgent societal need to reduce uncertainties associated with projections of future Antarctic Ice Sheet evolution, as these uncertainties propagate directly into uncertainties in projections of future sea-level change.
The Realistic Ice shelf ocean State Estimates (RISE) project aims to meet this need by coordinating the rapid advances in modelling and observations of ocean-driven melting of the Antarctic Ice Sheet. By combining an evaluation of circum-Antarctic ocean model results with observations, we will be able to provide improved constraints on both observed and projected contributions to sea level from the Antarctic Ice Sheet.
To date, ice sheet/ocean simulations give a wide scatter of ocean-driven basal melting, as a result of different approaches and frameworks. Current intercomparison projects, such as MISOMIP, are bringing ocean and ice sheet modellers together to advance the state-of-the-art in regional-scale simulations. Comparing ice sheet/ocean modelling results for the whole Antarctica will allow us to constrain both present and future ocean-driven impacts on Antarctica, and provide much needed evaluation with both satellite-derived and in-situ estimates of ice shelf basal melt rates. Currently, autonomous instruments are being deployed on top of ice shelves and can provide a time series of estimated ocean-driven basal mass loss. These deployments are part of a SOOS-endorsed project NECKLACE and their locations are already available through SOOSmap.
RISE is receiving support from the international ocean ice sheet community (e.g. CliC with ISMIP6 and MISOMIP projects, IACS and IAPSO). In parallel, RISE is already collecting circum-Antarctic basal melt estimates from leading international modelling groups. Through assessing present day basal melting and ocean states, we hope to guide the direction of future observations on and beneath ice shelves, thereby better integrating ice sheet/ice shelf-ocean observations and modelling.