Spatial and temporal variations of the Greenland Ice Sheet surface lake system
(English)Manuscript (preprint) (Other academic)
Surface lakes on the Greenland Ice Sheet provide temporary storage for meltwater that influences both the surface and basal water fluxes. Thus, to understand the effects of variations in surface melt on ice sheet dynamics it is necessary to understand the surface hydrology. We have used satellite imagery, acquired at 5-day intervals, to map lake initiation and cessation on two sub-sections on the south west Greenland Ice Sheet over three melt seasons (2007-2009). We observe that lake initiation is closely tied to a threshold energy input of approximately 40 ± 18.5 positive-degree-days. This applies for all studied melt season, regardless of evolution and melt index anomalies. Lake longivity averages 24 days with little variation between different melt seasons. Our observed median lake area is larger than previously reported. Approximately 50% of all lakes have a life span of <10 days. Cessation of identified lakes is caused by two processes: drainage during the melt season (88% 2007, 78% 2008 and 88% 2009) and freeze-up at the end of the season (12% 2007, 22% 2008 and 12% 2009). Inclusion of energy needed for lake initiation and amount of freeze-up lakes into supra-glacial lake models will add further insight into the hydrological system dynamics.
Research subject Physical Geography
IdentifiersURN: urn:nbn:se:su:diva-74505OAI: oai:DiVA.org:su-74505DiVA: diva2:510111