Wintertime storage of water in buried supraglacial lakes across the Greenland Ice Sheet

Abstract

Increased surface melt over the Greenland Ice Sheet (GrIS) is now estimated to account for half or more of the ice sheet's total mass loss. Here, we show that some meltwater is stored, over winter, in buried supraglacial lakes. We use airborne radar from Operation IceBridge between 2009 and 2012 to detect buried supraglacial lakes, and we find that they were distributed extensively around the GrIS margin through that period. Buried supraglacial lakes can persist through multiple winters and are, on average, ~ 1.9 + 0.2 m below the surface. Most buried supraglacial lakes exist with no surface expression of their occurrence in visible imagery. The few buried supraglacial lakes that do exhibit surface expression have a unique visible signature associated with a darker blue color where subsurface water is located. The volume of retained water in the buried supraglacial lakes is likely insignificant compared to the total mass loss from the GrIS, but the water may have important implications locally for the development of the englacial hydrologic system and ice temperatures. Buried supraglacial lakes represent a small but year-round source of meltwater in the GrIS hydrologic system.