Seasonal evolution of supraglacial lakes and rivers on the southwest Greenland Ice Sheet

• Published in: Journal of Glaciology
• Main Authors: Kang Yang, Laurence C. Smith, Matthew G. Cooper, Lincoln H. Pitcher, Dirk van As, Yao Lu, Xin Lu, Manchun Li
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press 2021
• Subjects: climate models; ice-sheet hydrology; remote sensing; supraglacial lakes; supraglacial rivers; surface mass balance; Environmental sciences; GE1-350; Meteorology. Climatology; QC851-999; Greenland; Merra; Ice Sheet; Journal of Glaciology
• Online Access: https://doi.org/10.1017/jog.2021.10; https://doaj.org/article/85536a934e4f4edf940981123faa0602

Supraglacial lakes and rivers dominate the storage and transport of meltwater on the southwest Greenland Ice Sheet (GrIS) surface. Despite functioning as interconnected hydrologic networks, supraglacial lakes and rivers are commonly studied as independent features, resulting in an incomplete understanding of their collective impact on meltwater storage and routing. We use Landsat 8 satellite imagery to assess the seasonal evolution of supraglacial lakes and rivers on the southwest GrIS during the 2015 melt season. Remotely sensed meltwater areas and volumes are compared with surface runoff simulations from three climate models (MERRA-2, MAR 3.6 and RACMO 2.3), and with in situ observations of proglacial discharge in the Watson River. We find: (1) at elevations >1600 m, 21% of supraglacial lakes and 28% of supraglacial rivers drain into moulins, signifying the presence of high-elevation surface-to-bed meltwater connections even during a colder-than-average melt season; (2) while supraglacial lakes dominate instantaneous surface meltwater storage, supraglacial rivers dominate total surface meltwater area and discharge; (3) the combined surface area of supraglacial lakes and rivers is strongly correlated with modeled surface runoff; and (4) of the three models examined here, MERRA-2 runoff yields the highest overall correlation with observed proglacial discharge in the Watson River.