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Center for Nonlinear Studies |
The Greenland Ice Sheet is currently experiencing significant ice loss associated with a warming climate. Outlet glaciers are speeding up and calving more ice into the ocean. Also, the surface melt generated on Greenland is increasing. The meltwater runs off and penetrates the ice through the cryo-hydrologic system before reaching the bed and draining to the ocean. Increased meltwater 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 meltwater 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 the 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 and increasing Greenland’s contribution to sea-level rise.
Host: Bill Lipscomb