Surface meltwater runoff routing through a coupled supraglacial-proglacial drainage system, Inglefield Land, northwest Greenland

The northwest Greenland Ice Sheet (NW GrIS) is rapidly losing mass, and its ablation zone has expanded over the past two decades. Numerous supraglacial streams flowing directly NW GrIS surface drain a large lobe of grounded ice at Inglefield Land, into proglacial Minturn River Nares Strait. Owing to absence moulins crevasses, this continuous supraglacial-proglacial drainage system regulates evacuation meltwater from sheet ocean. We examine Land coupled during 2016–2019 melt seasons (July August), using 137 Sentinel-2 Landsat-8 visible/near-infrared satellite images. Two water metrics (supraglacial area fraction Am river effective width We) are used track spatio-temporal variations moving through system. Satellite-derived also compared with daily runoff simulations MAR v3.11 MERRA-2 climate/SMB models, estimate routing lag times assess model performance. highly correlated (r2 = 0.85, p < 0.01), indicating that evacuates ocean negligible subglacial storage or delays. Both remotely sensed positively modeled runoff, especially 0.81 0.77 for We, vs. 0.66 0.64 MERRA-2). Lagged (2 days, r2 0.87 0.82) match both better than simultaneous optimal time 2 d. conclude 1) unlike southwest GrIS, routes off zone, virtually no capture by moulins; 2) most ∼2 d transit occurs on rather in zone; 3) multi-temporal imaging facilitates holistic, source-to-sink tracking global