A dataset of GPS-observed daily displacements for hydrogeodetic studies over Europe

We use more than 5,000 Global Positioning System (GPS) permanent stations whose observations are processed by the Nevada Geodetic Laboratory (NGL) and located in Europe to classify them as reliable for hydrogeodetic studies, a so-called hydrogeodetic benchmarks. Benchmarks are defined by investigating whether the GPS-observed daily vertical displacements are positively and significantly correlated with hydrological model, whose Terrestrial Water Storage (TWS) estimates are converted into model-predicted daily vertical displacements. Due to the complexity of the hydrospheric phenomenon, we propose that these correlations are considered at three different temporal scales, assumed a-priori as short-term, seasonal and long-term. First, the GPS-observed vertical displacements are decomposed using non-parametric wavelet decomposition and then, we correlate these decomposed displacements with high-resolution nested regional Community Land Model 5.0 (CLM5), which is more reliable than global models and represents the spatial resolution of 12 km. We prove that GPS-observed displacements at benchmark points show high correspondence to the vertical displacements derived by GRACE (Gravity Recovery and Climate Experiment). We then use these benchmarked points and invert the GPS-observed displacements into TWS fields for several European basins. We demonstrate that these TWS estimates exhibit consistent and interpretable spatial patterns and are better correlated at all three temporal scales with external datasets, such as climate indices, than TWS estimates derived from the conventional approach used to date. The research is crucial for future hydrogeodetic analyses that take a step forward towards daily temporal resolution of hydrosphere-related products.