Ice‐shelf basal melt channels stabilized by secondary flow

• Published in: Geophysical Research Letters
• Main Authors: Wearing, M.G., Stevens, L.A., Dutrieux, P., Kingslake, J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2021
• Subjects: Antarctic; Antarc*; Ice Shelf; Ice Shelves
• Online Access: http://nora.nerc.ac.uk/id/eprint/531273/; https://nora.nerc.ac.uk/id/eprint/531273/1/2021GL094872.pdf; https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL094872

Ice-shelf basal channels form due to concentrated submarine melting. They are present in many Antarctic ice shelves and can reduce ice-shelf structural integrity, potentially destabilizing ice shelves by full-depth incision. Here, we describe the viscous ice response to a basal channel - secondary flow - which acts perpendicular to the channel axis and is induced by gradients in ice thickness. We use a full-Stokes ice-flow model to systematically assess the transient evolution of a basal channel in the presence of melting. Secondary flow increases with channel size and reduces the rate of channel incision, such that linear extrapolation or the Shallow-Shelf Approximation cannot project future channel evolution. For thick ice shelves (> 600 m) secondary flow potentially stabilizes the channel, but is insufficient to significantly delay breakthrough for thinner ice (< 400 m). Using synthetic data, we assess the impact of secondary flow when inferring basal-channel melt rates from satellite observations.