Investigating seasonal basal properties in Greenland through ice velocity inversion

Surface melt runoff at the margins of the Greenland Ice Sheet has long been linked to seasonal surface velocity changes caused by water lubricating the base of the ice sheet and enhancing basal sliding. The relationship between seasonal runoff and velocity patterns has been studied and other behaviors besides increased sliding have been found. This suggests a link to different states of basal drainage systems and basal properties (Moon et al., 2014; Solgaard et al., 2022). We investigate the impact of surface melt runoff on the dynamics of the Greenland Ice Sheet margins by determining basal properties. Using the finite element ice flow model Úa (Gudmundsson et al., 2012) constrained by surface velocities from the PROMICE velocity product (Solgaard et al., 2021), we invert for the ice rate factor A and basal slipperiness C. This approach allows us to investigate the effect of surface melt water on ice velocities and is an important step towards improving the sensitivity of ice flow models to seasonal climate variations.