Same lake?
A common feature of catchments adjoining the Greenland ice sheet is the occurrence of glacial lake outburst floods (GLOFs), which occur when the water volume stored in an ice-dammed lake becomes sufficient to lift the ice barrier blocking its path downstream. We identified 15 GLOFs originating from a single source lake (marked A in Fig. 1 and fig. S1) (see Materials and Methods and fig. S5). Because the typical interval between GLOFs is on the order of several years, they introduce noise in the relationship between annual discharge and climate forcing. Consequently, we chose to discard the additional water released to the larger catchment during the GLOFs by linear interpolation to cut off the peak in discharge time series between onset and end of each GLOF, as determined by the daily discharge rate of change (fig. S3). The result is a detailed 40-year time series of daily mean discharge as annual hydrographs, with observational gaps and identified peaks from GLOFs (Fig. 2).
