Solid Earth deformation in Greenland observed by the Greenland’s GNSS Network

The Greenland ice sheet has lost significant mass over the past two decades. More than 58 permanent Global Navigation Satellite System (GNSS) stations on bedrock, which are part of Greenland’s GNSS Network (GNET), measure the deformation continuously. The solid Earth displacement processes are two-fold: an instantaneous elastic deformation and a slow viscoelastic deformation, which can be attributed to glacial isostatic adjustment (GIA). We have gained new insight into both vertical and horizontal land movement by removing the elastic deformation with high-resolution mass change grids.

By including mass change from Greenland and Arctic Canada peripheral glaciers, our estimates for the vertical GNSS velocities align with GIA models, though significant regional discrepancies remain. For the horizontal GNSS velocity component, new Euler poles describing the North American plate where fitted, which is the majority of the horizontal observed GNSS velocity. We compared our inferred horizontal GIA deformation with 26 1D GIA models. We discovered a significant inward contraction field in South Greenland, originating from the Laurentide ice sheet that the GIA models cannot capture. A complete North, East, and Up inferred GIA velocity field for Greenland can be used as a constraint for both GIA models and to target stations with abnormal behaviour where mass change estimates should be improved.