Roughness of Ice Shelves Is Correlated With Basal Melt Rates

Abstract

Ice shelf collapse could trigger widespread retreat of marine-based portions of the Antarctic ice sheet. However, little is known about the processes that control the stability of ice shelves. Recent observations have revealed that ice shelves have topographic features that span a spectrum of wavelengths, including basal channels and crevasses. Here we use ground-penetrating radar data to quantify patterns of roughness within and between ice shelves. We find that roughness follows a power law with the scaling exponent approximately constant between ice shelves. However, the level of roughness varies by nearly an order of magnitude between ice shelves. Critically, we find that roughness strongly correlates with basal melt, suggesting that increased melt not only leads to larger melt channels, but also to increased fracturing, rifting and decreased ice shelf stability. This hints that the mechanical stability of ice shelves may be more tightly controlled by ocean forcing than previously thought.