Distribution and Morphometry of Large Supraglacial Channels on Five Antarctic Ice Shelves

Supraglacial channels play a crucial role in glacial hydrology by transporting meltwater across ice sheets and ice shelves. Despite their importance, recent research has tended to focus on the storage of supraglacial meltwater (e.g., in lakes), and our understanding of the distribution and connectivity of channels is more limited, particularly in Antarctica. Here we investigate large supraglacial channels (i.e., width > 20 m) on five contrasting ice shelves in Antarctica during the melt seasons of 2020 and 2022. Supraglacial channels are mapped by applying an automated delineation method to Landsat-8 satellite imagery, and various metrics are calculated to comprehensively describe their fluvial morphometry. Results show that supraglacial channels are extensive on all five ice shelves, forming a total of 119 channel networks with significantly different drainage patterns. Channel networks exhibit relatively simple structures but large in extent and occur on low ice surface slopes (<0.001) and low elevations (< 70 m) where ice is slow-flowing (<150 m a^-1). The orientation of channels broadly coincides with the ice flow direction, and they are clearly influenced by surface flow structures (e.g., longitudinal flow-stripes), which appear to exert a clear control on both channel formation and their morphological properties. Future research will focus on temporal (i.e., seasonal and interannual) analysis of channels on each ice shelf by using Sentinel-2 imagery.