Ice‐shelf basal melt channels stabilized by secondary flow
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.
Authors: Wearing, M.G., Stevens, L.A., Dutrieux, P. ORCID record for P. Dutrieux, Kingslake, J.