A land uplift model in Fennoscandia combining GRACE and absolute gravimetry data

Since 2002 the GRACE satellite mission provides monthly solutions of the Earth’s gravity field reflecting mass variations on various spatial and temporal scales. The glacial isostatic adjustment (GIA)-induced trend signal in Fennoscandia can be obtained with a spatial resolution of about 300–400 km. Moreover, since 2003 the Institut für Erdmessung has carried out absolute gravity (AG) measurements in Fennoscandia in close cooperation with the Scandinavian partners. From the AG data, point-wise mass variations at the AG sites have been determined including the GIA-induced trend signal. For direct comparison of those point values with regional results from GRACE, vertical movements of the sites have been considered using rates determined from permanent GPS measurements. The various results for GIA-related effects agree well near the uplift center, although the different raw data contain different signal contributions. In a final step, we combine the AG trend values (including GPS rates) and the GRACE results to obtain a data-based solution of the present-day secular mass variation in Fennoscandia. we present results of the individual techniques as well as the combined solution, where we also discuss possible errors sources.