Supraglacial lake evolution on the Greenland Ice Sheet

• Main Author: Waddington, Humphrey John
• Format: Master Thesis
• Language: English
• Published: Scott Polar Research Institute, University of Cambridge 2009
• Subjects: Greenland; glacier; Ice Sheet; Jakobshavn
• Online Access: https://doi.org/10.17863/CAM.23289; https://www.repository.cam.ac.uk/handle/1810/276009

Abstract. Supraglacial lakes form annually on the surface of the Greenland Ice Sheet around Paakitsoq, north of the Jakobshavn Isbrae outlet glacier. The lakes are ephemeral, drain through moulins or crevasses at their bed throughout the melt season, and deliver large volumes of water to the subglacial hydrological system. Such inputs of water can cause spatially and temporally constrained speed-up events affecting the normally slow, marginally-terminating inland ice flow regimes. This dynamic response of the Greenland Ice Sheet to increased basal lubrication is likely to be influenced under global warming scenarios as more meltwater will be produced with increased temperatures. An understanding of the evolution of supraglacial lakes is helpful to understanding the volumes of water delivered to the subglacial hydrological system, and the present study focusing on Paakitsoq investigates lake volume evolution as observed in satellite imagery collected through the melt season in 2008, and through the use of a numerical model to predict lake inputs. The surface energy balance model used is a more advanced numerical model than has been used in previous study and model results are mixed. Conclusions are drawn from model and observed results, and suggest that with further investigation and manipulation, the model may provide accurate results that represent true melt water volumes, and the patterns of observed supraglacial lake evolution on the surface of the Greenland Ice Sheet. It is suggested that the present and future studies on surface lake evolution on the ice sheet would benefit from the collection of data from the Paakitsoq ice surface and from a higher resolution digital elevation model.