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The GRACE mission has had a revolutionary impact on the study of Earth system processes, but it provides a band‐limited representation of mass changes. This is particularly problematic when studying mass changes that tend to be concentrated in fairly narrow zones near the edges of the Greenland Ice Sheet. In this study, coarse‐resolution estimates of the mass change derived from GRACE have been enhanced by the introduction of heuristic scaling factors applied to model surface mass balance and observed surface elevation change. Corresponding results indicate large spatial heterogeneity in the gridded scaling factors at the 0.5° × 0.5° scale, reflecting significant mass losses concentrated along the ice sheet margin and relatively small internal ice sheet changes at higher elevations. The scaled GRACE‐derived vertical displacements are in the range from −2 to 14 mm/year from 2003 to 2015. The Greenland GPS network was used to examine the downscaling GRACE predictions of the crustal displacements. The results show consistency of scaled GRACE‐predicted and GPS‐observed seasonal and long‐term uplift in major drainage basins of Greenland. Our results indicate that GRACE predictions underestimate vertical displacements at sites located in regions characterized by concentrated loads, but perform well in other regions. Differences between predicted and observed uplift rates are mainly caused by the sensitivity kernels, because GPS and GRACE estimates are based on weighted averages of mass loss in different sensitivity ranges. Moreover, a large uncertainty in the glacial isostatic adjustment correction may also cause errors in the GPS‐to‐GRACE ratio. Key Points: GRACE results can be improved by using scaling factors estimated from two models of surface mass fields in GreenlandScaled GRACE‐derived and GPS‐observed vertical displacements were compared at 53 Greenland GPS Network (GNET) stationsGRACE‐based estimates of accurate uplift rates in Greenland needs to consider the spatial pattern of ice loss and reliable GIA correction [ABSTRACT FROM AUTHOR]

Abstract: The continuously operating Global Positioning System (GPS) sites mounted on bedrock around the coast of Greenland provide important geodetic data sets to quantify the solid Earth's response to historical and present‐day ice mass variations. However, the presence of colored noise and irregular seasonal signals makes it difficult to detect transient changes in GPS time series. Here we apply the multichannel singular spectral analysis to the combination of GPS data and Gravity Recovery and Climate Experiment (GRACE) data so that we can identify and fully utilize the spatial correlations from these two independent data sets. Using the GPS and GRACE data near Upernavik Isstrøm in West Greenland as an example, we demonstrate that this method successfully detects two transient signals in ice mass variations during 2008 and 2014. Our forward modeling of loading displacements due to changes in surface mass balance (SMB) and ice dynamics suggests that the transient change starting in mid‐2008 was due to the combined contributions from dynamically induced mass loss and SMB. The transient change starting in mid‐2011 was mainly due to ablation. Specifically, the ice melted more in 2012 and less in 2013 with little contribution from anomalies in accumulation. [ABSTRACT FROM AUTHOR]