The characterization of the cryo-hydrologic system of the Sermeq Avannarleq Glacier in Greenland and its influence on ice temperature.

摘要

The Greenland Ice Sheet is currently experiencing a large amount of ice loss due to the warming climate. The outlet glaciers are speeding up and calving more ice into the ocean, leading to sea level rise. This is an enormous risk for the coastal regions where increased flooding has to be expected. The Greenland Ice Sheet and the Antarctic Ice Sheet have the potential to increase the present sea level by 67 m. Hence there is a need to understand the current state of the ice sheets and possible future scenarios. The surface melt generated on Greenland is increasing. The melt water runs off, penetrates the ice through the cryo-hydrologic system before reaching the bed and draining to the ocean. Increased melt water flow leads to basal lubrication and also has the potential to warm the ice, thus decreasing its viscosity and increasing ice discharge.;Most ice sheet models do not incorporate a link between enhanced melt water flow and ice temperature calculations. This work quantifies heat transfer from the cryo-hydrologic system as a mechanism for warming glacier ice. A fuzzy logic model is used to analyze the ablation zone of the Sermeq Avannarleq Glacier in western Greenland for potential moulin locations and hence constrain water input into the ice. A dual-column cryo-hydrologic heat exchange model is introduced to couple ice temperatures to increased cryo-hydrologic activity. A steady-state flowline model is used to demonstrate the rapid warming of the ice sheet due to cryo-hydrologic network and the increase in melt area due to the rising equilibrium line.;The results presented here indicate that current model approaches may underestimate the ice temperatures in the ablation zone. The cryo-hydrologic network has the potential to warm an ice sheet within decades, changing its physical properties in a changing climate.