Loading effects on the Earth’s crust from GPS and gravity observations compared to models

Time series of GPS height and gravity data at co-located stations have been analyzed. The network of stations is located in the North eastern part of Italy. At the Medicina station, located in the South eastern part of the Po valley, decadal GPS height and absolute gravity measurements as well as superconducting gravimeter time series are available. At the other stations of the network, GPS height and absolute gravity measurements are regularly acquired. After estimating long-term linear trends, we compare the seasonal oscillations present both in GPS height and gravity data series. The amplitude of these oscillations is in the order of 1 to 2 cm peak to peak for the GPS heights and 4 to 6 µGal for the gravity observations. We built models representing the atmospheric, hydrologic and non-tidal ocean loading. These models are compared to the observed oscillations.