资源环境科技发展态势分析平台

Meltwater inputs to moulins regulate Greenland Ice Sheet sliding speeds by controlling water pressure in the most connected regions of the subglacial drainage system. While moulin storage capacities are a critical control on subglacial water pressure, few observations exist to constrain storage. Using direct observations inside moulins, we show that moulin cross‐sectional areas can be at least 500 m², far greater than is observed at the surface or assumed in models. Moulin water level measurements and numerical modeling reveal that diurnal variability in moulin water pressure is highly attenuated in moulins with large storage volumes (~3% ice pressure), relative to moulins with smaller storage volumes (~25% ice pressure). Because large variability in moulin water pressure is linked to processes that ultimately reduce ice sliding speeds, ice sliding speeds in areas drained by large moulins may be more sensitive to long‐term increases in meltwater than areas drained by small moulins.