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.

中文翻译：

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格陵兰冰盖西南部冰上湖泊和河流的季节演化

冰上湖泊和河流主导着格陵兰岛西南冰盖 (GrIS) 表面融水的储存和运输。尽管作为相互连接的水文网络发挥作用，但冰上湖泊和河流通常作为独立的特征进行研究，导致对其对融水储存和路线的集体影响的理解不完整。我们使用 Landsat 8 卫星图像来评估 2015 年融化季节期间 GrIS 西南部的冰上湖泊和河流的季节性演变。将遥感融水面积和体积与来自三个气候模型（MERRA-2、MAR 3.6 和 RACMO 2.3）的地表径流模拟进行比较，并与沃森河的前冰期排放进行现场观测。我们发现：（1）在海拔 >1600 m 处，21% 的冰上湖泊和 28% 的冰上河流流入红磨坊，表明即使在低于平均水平的融化季节，也存在高海拔地表融水连接；(2) 冰上湖泊在瞬时地表融水储存量中占主导地位，而冰上河流则在地表融水总面积和排放量中占主导地位；(3) 冰上湖泊和河流的总表面积与模拟的地表径流密切相关；(4) 在这里检查的三个模型中，MERRA-2 径流与观察到的沃森河前冰期流量的总体相关性最高。(3) 冰上湖泊和河流的总表面积与模拟的地表径流密切相关；(4) 在这里检查的三个模型中，MERRA-2 径流与观察到的沃森河前冰期流量的总体相关性最高。(3) 冰上湖泊和河流的总表面积与模拟的地表径流密切相关；(4) 在这里检查的三个模型中，MERRA-2 径流与观察到的沃森河前冰期流量的总体相关性最高。