Vienna Terrestrial Reference Frame S/X 2020 for VLBI scale study

Context and methodology S0: 1980.0-2021.0, S/X VLBI sessions with more than 3 stations S1: 1980.0-2021.0, S/X VLBI sessions with more than 3 stations + 4 additional discontinuity breaks for NYALES20 due to PDIM (proposed by Le Bail. 2023) S2: 1980.0-2021.0, S/X VLBI sessions with more than 3 stations + 2 additional discontinuity breaks for NYALES20 due to PDIM (realized in ITRF2020-u2023 ( IERS ITRF Center 2024 )) These terrestrial reference frames were used to calculate session-wise estimated VLBI scale factors to analyse the impact of a modfied station movement model for the VLBI station NYALES20 (Norway, Svalbard) on the VLBI scale.

Thus, additional discontinuity intervals have been introduced in the determination of S1 and S2 to more accurately account for the climate change-related processes happening in Svalbard. The two reference frames were computed using VieCompy ( Kern et al. 2023 ), a combination software under the umbrella of VieVS (Vienna VLBI and Satellite Software; Böhm et al. 2018 ) written in Python. The corresponding publication with the title Terrestrial Reference Frame Scale Drift Anomalies in VLBI and the Contribution of Ny-Ålesund Radio Telescopes has been submitted to the Earth, Planets and Space Journal.