Distribution and morphometry of large supraglacial channels on five Antarctic ice shelves

Abstract Supraglacial channels play a crucial role in 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 (>30 m wide) supraglacial channels 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 quantify and describe their fluvial morphometry. Results show that supraglacial channels are extensive on all five ice shelves, forming a total of 119 channel networks that exhibit relatively simple structures that do not exceed fourth-order Strahler ordering and which mostly occur on low ice surface slopes (<0.001) and at low elevations where ice is slow-flowing (<150 m a −1 ). The orientation of channels broadly coincides with the ice flow direction and is clearly influenced by surface structures (e.g. longitudinal flow-stripes), which appear to exert a strong control on both channel formation and their morphological properties.