Context and objectives
Ice shelves – the floating extensions of ice sheets - play a crucial role in controlling the present-day mass loss of the Antarctic ice sheet. Basically, ice shelves act as a cork on a bottle and restrain the inland ice through what is known as buttressing. Ice-shelf change is particularly pronounced in West Antarctica in response to increased oceanic heat transport beneath its floating ice shelf and resulting feedbacks, but evidence from around Antarctica confirms that the effect is not geographically limited. Ice-shelf thinning causes an instantaneous acceleration and a retreat of the grounding-line (limit between the grounded ice sheet and the floating ice shelf), hence a rise in sea level, which has major consequences for society.
One difficulty in studying Antarctic ice shelves arises from their unsteady nature. The ice geometry is evolving rapidly (years), ice is being advected at speeds >1 km/yr whilst the ocean beneath is expected to respond at sub-annual scales. In addition, there are many reasons to expect that the spatial pattern of melt is complex, where sub-shelf melting is concentrated in weaker zones of ice shelves, such as longitudinal bottom channels. Only a few studies have been focused on the spatial pattern, which requires high-resolution interferometrically-determined ice flow velocities and surface elevation and changes herein. Their application therefore remains limited to specific ice shelves or ice shelf sections for a particular snapshot in time, which is not useful for wider mapping, monitoring and impact assessment, which will be addressed in MIMO.
The main objective of MIMO is to quantify basal melt of ice shelves surrounding the Antarctic ice sheet at high spatial and temporal resolution (monitoring) to derive improved parametrizations for use in ice sheet modelling studies. The latter will also be implemented in a state-of-the-art ice-sheet model and compared to currently available datasets. Since basal melting under ice shelves is not only a great unknown, its spatial and temporal change is even more so. Monitoring changes in ice shelves is considered of utmost importance in understanding and projecting future impacts of climate change on sea level.
Expected scientific results
Besides a better knowledge of basal mass balance of ice shelves, the project will also deliver new high-resolution surface topography and ice thickness maps as well as surface velocity data, which are all beneficial to a wider scientific community. Basal melt rates will be employed to investigate new parametrizations of basal melt rate underneath ice shelves as a function of local geometry and ocean parameters.
Expected products and services
• Surface velocities of ice shelves
• Ice thickness of ice shelves
• Surface topography of ice shelves
• Advanced and adapted SAR processor for Sentinel-1 SAR data
Climate scientists, polar researchers, mapping, ice sheet model projections of sea-level change