Detection of ice mass variation using gnss measurements at Svalbard

We compare observed uplift rates of Global Navigation Satellite Systems (gnss) with geophysical predictions at sites located on Spitsbergen. We show here that using modern postglacial rebound models, realistic mass balance for Present Day Ice Melting (pdim) and taking the deglaciation of the Little Ice Age (lia) into account, we can close the overall uplift budget at a level of a few millimetres per year. For this study we used gnss data from well-established geodetic sites in Ny-Ålesund and the new data from Hornsund. The significant increase of uplift rates since the beginning of 2011 was observed at both gnss sites. These height changes are attributed to recent increased ice mass loss of 6.0 Gt yr−1 for Svalbard. The total mass loss is estimated at 14.7 Gt yr−1. Ice unloading caused also a noticeable increase of distance between Ny-Ålesund and Hornsund. We show that the specific location of the two sites facilitates inference of differential mass loss within the Svalbard Archipelago.