Topographic Shelf Waves Control Seasonal Melting Near Antarctic Ice Shelf Grounding Lines

• Published in: Geophysical Research Letters
• Main Authors: Sun, Sainan, Hattermann, Tore, Pattyn, Frank, Nicholls, Keith W., Drews, Reinhard, Berger, Sophie
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2019
• Subjects: F800 Physical and Terrestrial Geographical and Environmental Sciences; F900 Others in Physical Sciences; Antarctic; East Antarctica; Gunnerus Bank; Roi Baudouin; Antarc*; Antarctica; Ice Shelf; Ice Shelves
• Online Access: https://nrl.northumbria.ac.uk/id/eprint/47283/; https://doi.org/10.1029/2019GL083881; https://nrl.northumbria.ac.uk/id/eprint/47283/1/2019GL083881.pdf

The buttressing potential of ice shelves is modulated by changes in subshelf melting, in response to changing ocean conditions. We analyze the temporal variability in subshelf melting using an autonomous phase-sensitive radio-echo sounder near the grounding line of the Roi Baudouin Ice Shelf in East Antarctica. When combined with additional oceanographic evidence of seasonal variations in the stratification and the amplification of diurnal tides around the shelf break topography (Gunnerus Bank), the results suggest an intricate mechanism in which topographic waves control the seasonal melt rate variability near the grounding line. This mechanism has not been considered before and has the potential to enhance local melt rates without advecting different water masses. As topographic waves seem to strengthen in a stratified ocean, the freshening of Antarctic surface water, predicted by observations and models, is likely to increase future basal melting in this area.