Investigating potential controls on rapid surface lake drainage in West Greenland

The controls on rapid supraglacial lake drainage on the Greenland Ice Sheet (GrIS) remain uncertain, making it difficult to incorporate rapid lake drainage into models of GrIS hydrology, or to determine the present and future ice-dynamic impact of large meltwater pulses delivered to the ice-sheet bed. Here, we first used a fully automated algorithm to track changes to supraglacial lake areas and volumes to identify rapidly draining lakes within the land-terminating Paakitsoq and marine-terminating Store Glacier regions of West Greenland during summer 2014. Second, we derived data on various possible hydrological, morphological, glaciological, and surface-mass-balance factors that might influence rapid lake drainage. Third, these data were used within an Exploratory Data Analysis (EDA) framework, which examined the statistical differences between the samples of rapidly and non-rapidly draining lakes, and the correlations between the lake areas and volumes, and the potential controls. Our results showed that the rapidly draining and non-rapidly draining lakes were statistically indistinguishable for nearly all of the controls investigated (except for lake area), showing that they were drawn from the same population. This could be because rapid lake drainage is controlled by one or multiple processes that were unresolvable in the data (for example, the pre-existence of weaknesses in the ice beneath lake basins) or because rapid lake drainage events have a strong random or stochastic element.