The Impact of Non-tidal Surface Loading on GNSS Products: Assessing GFZ's Repro3 Solution

Time-dependent mass variations of near-surface geophysical fluids in the atmosphere, the oceans, and the continental hydrosphere lead to significant and systematic load-induced deformations of the Earth's crust. These deformations impact the space geodetic techniques; thus, uncorrected deformations can be seen in the estimated parameters such as station positions and Earth rotation parameters. While corresponding loading corrections were not applied in the recent third reprocessing campaign (IGS repro3) of the International GNSS Service, derived products contain related seasonal signals. We repeated the GFZ repro3 effort by applying the ESMGFZ models at the observation level to assess their impact and analyze the potential benefits of correcting surface loading. GFZ's contribution to repro3 includes more than 300 globally distributed stations and the satellite systems GPS, GLONASS, and Galileo. By comparing both solutions, we will discuss the impact of non-tidal surface loading corrections on GNSS products. This assessment will focus on estimated seasonal signals and the remaining coordinate repeatabilities for the station coordinates. Based on previous studies, improvements are expected for around 80% of the considered stations. In this contribution, we will primarily discuss the remaining stations.