Response of supraglacial rivers and lakes to ice flow and surface melt on the northeastern Greenland Ice Sheet during 2016-2018 melt seasons

The northeastern Greenland Ice Sheet (GrIS) is now undergoing substantial mass loss and receiving more attention. Supraglacial rivers and lakes are two important parts of supraglacial hydrology system, influencing the ice surface mass balance and ice sheet dynamics in this area. However, their fluvial geomorphometric characteristics have been poorly quantified and their response to ice flow and surface melt is still not clear. We extract supraglacial rivers and lakes on the northeastern GrIS (area ~68, 000 km²) using 10 m Sentinel-2 multispectral satellite imagery and 2 m ArcticDEM data acquired during 2016-2018 melt seasons. Moreover, we partition the northeastern GrIS into three basins with variable ice flow velocities (i.e. two fast-flowing basins and one slow-flowing basin) and investigate the relationship between regional climate model (RCM) surface melt with satellite-mapped supraglacial rivers and lakes in those basins. In the slow-flowing basin, supraglacial rivers are dendritic and lowly sinuous, and supraglacial lakes are rare. In the two fast-flowing basins, lowly sinuous supraglacial rivers and several large supraglacial lakes (area ~5 km²) high up on the inland ice sheet (elevation ~1200 m) transform into highly sinuous supraglacial rivers and numerous small lakes (area ~500 m²) on the outlet glacier (elevation <600 m). Interannual and intraseasonal evolutions of supraglacial rivers and lakes are mainly influenced by ice flow and surface melt. From 2016 to 2018, inland supraglacial rivers and lakes migrate to two outlet glaciers in the two fast-flowing basins, whereas remain stable in the slow-flowing basin. As a melt season progresses, supraglacial rivers and lakes newly form at high elevations. Moreover, we find a positive relationship between satellite-mapped supraglacial hydrology and RCM surface melt . In sum, this study conducts a preliminary investigation of supraglacial rivers and lakes on the poorly-studied northeastern GrIS and reveals their responses to ice flow and surface melt, which may improve our understanding of the relationship between Greenland supraglacial hydrology and mass balance.