Figure S7. Correlations between calculated subglacial storage
proxies and ice motion: (a) GPS-derived storage proxy S (surface
elevation), (b) GPS-derived change in storage, ΔS (surface elevation
derivative) (c) meltwater-derived storage proxy S (cumulative input-
output), and (d) meltwater-derived change in storage, ΔS (6h
input-output). These correlations use a cross-correlation value of 0
(e.g. no time offset correction to ice velocity). Linear correlations
(r ) and p -values indicating statistical significance
(p ) are shown in the bottom right corner of each plot.
Discharge-difference ΔS shows strongest overall correlation with ice
speed (r =0.79, panel d).