Supraglacial rivers on the northwest Greenland Ice Sheet, Devon Ice Cap, and Barnes Ice Cap mapped using Sentinel-2 imagery

Abstract

Supraglacial rivers set efficacy and time lags by which surface meltwater is routed to the englacial, subglacial, and proglacial portions of ice masses. However, these hydrologic features remain poorly studied mainly because they are too narrow (typically <30 m) to be reliably delineated in conventional moderate-resolution satellite images (e.g., 30 m Landsat-8 imagery). This study demonstrates the utility of 10 m Sentinel-2 Multi-Spectral Instrument images to map supraglacial rivers on the northwest Greenland Ice Sheet, Devon Ice Cap, and Barnes Ice Cap, covering a total area of ~ 10,000 km 2. Sentinel-2 and Landsat-8 both capture overall supraglacial drainage patterns, but Sentinel-2 images are superior to Landsat-8 images for delineating narrow and continuous supraglacial rivers. Sentinel-2 mapping across the three study areas reveals a variety of supraglacial drainage patterns. In northwest Greenland near Inglefield Land, subparallel supraglacial rivers up to 55 km long drain meltwater directly off the ice sheet onto the proglacial zone. On the Devon and the Barnes ice caps, shorter supraglacial rivers (up to 15-30 km long) are commonly interrupted by moulins, which drain internally drained catchments on the ice surface to subglacial systems. We conclude that Sentinel-2 offers strong potential for investigating supraglacial meltwater drainage patterns and improving our understanding of the hydrological conditions of ice masses globally.

Diverse supraglacial drainage patterns on the Devon ice Cap, Arctic Canada

“…In general, large supraglacial river networks have only recently begun attracting scientific attention with most studies focused on the Greenland Ice Sheet (Colgan et al, 2011;Crozier et al, 2018;Gleason et al, 2016;Ignéczi et al, 2018;King et al, 2016;Lampkin & Vanderberg, 2014;Legleiter et al, 2014;Poinar et al, 2015;Smith et al, 2015;Smith et al, 2017;. Yang et al (2019a) mapped small areas of the Devon and Barnes Ice Caps (as well as the northwest Greenland Ice Sheet) using 10 m Sentinel-2 visible/near-infrared satellite images and found that the drainage patterns and densities of supraglacial river networks may differ significantly within and between different ice masses.…”

The age of surface-exposed ice along the northern margin of the Greenland Ice Sheet

“…Their multispectral visible-wavelength sensors have a fine radiometric resolution (12-bit), similar to Landsat-8, enabling reliable detection of subtle changes in surface reflectance at a 10-m spatial resolution regularly (e.g. Fahnestock and others, 2016; Yang and others, 2019). While multiple other high-sensitivity visible-wavelength multispectral sensors now exist, including Landsat-8 and the WV constellation, we opted to primarily use S2 imagery for the examination of the GrIS surface stratigraphy.…”

The age of surface-exposed ice along the northern margin of the Greenland Ice Sheet

“…Their multispectral visible-wavelength sensors have a fine radiometric resolution (12-bit), similar to Landsat-8, enabling reliable detection of subtle changes in surface reflectance at a 10-m spatial resolution regularly (e.g. Fahnestock and others, 2016;Yang and others, 2019). While multiple other highsensitivity visible-wavelength multispectral sensors now exist, including Landsat-8 and the WV constellation, we opted to primarily use S2 imagery for the examination of the GrIS surface stratigraphy.…”