资源环境科技发展态势分析平台

Firn aquifers have been discovered across regions of the Greenland ice sheet with high snow accumulation and melt rates, but the processes and rates that sustain these aquifers have not been fully quantified or supported by field data. A quantitative description of the hydrology of a firn aquifer upslope from Helheim Glacier that integrates field measurements is presented to constrain melt and recharge rates and timing, temporal variations in temperature and water levels, and liquid‐water residence time. Field measurements include weather data, firn temperatures, water levels, geochemical tracers, and airborne radar data. Field measurements show that once the firn column is temperate (0 °C), meltwater from the surface infiltrates to the water table in less than 2 days and raises the water table. Estimates of recharge rates range between 13 and 33 cm/yr, with an average of 22 cm/yr. Meltwater within the recently formed aquifer, which flows laterally downslope and likely discharges into crevasses, has a mean residence time of ~6 years. Airborne radar data suggest that the aquifer in the study area continues to expand inland, presumably from Arctic warming. These comprehensive field measurements and integrated description of aquifer hydrology provide a comprehensive, quantitative framework for modeling fluid flow through firn, and understanding existing and yet undiscovered firn aquifers, and may help researchers evaluate the role of firn aquifers in climate change impacts.