Space and time variability of height and gravity in Northeastern Italy

Hydrological mass variations play a major role in the long and seasonal height and gravity variability. On decadal time scale, environment-related variations of GPS height and gravity have not yet been clearly identified mainly because of the temporal extent of most of the available records. We have studied GPS height, gravity and hydrological time series in northeastern Italy with the aim to identify significant common patterns in the space and time domains by using a Principal Component analysis. Both over long and short time scales, GPS height series show signals induced by different phenomena, for example, those related to mass transport in the Earth system. However, it is not easy to unravel the contribution of the different components in the observed behavior. At GPS sites, the information provided by superconducting gravimeter observations and/or absolute gravity measurements offers a unique means to detect and understand mass contributions.