Continuous Global Positioning System (GPS) observations have been logged at the Finnish Antarctic research station (Aboa) since February 2003. The station is located in Dronning Maud Land, East Antarctica. Almost 5000 daily observation files have been archived based on yearly scientific expeditions. These files have not been fully analysed until now. This study reports for the first time on the consistent and homogeneous data processing and analysis of the 15-year long time series. Daily coordinates are obtained using Precise Point Positioning (PPP) processing based on two approaches. The first approach is based on the Kalman filter and uses the RTKLIB open source library to produce daily solutions by unconventionally running the filter in the forward and backward direction. The second approach uses APPS web service and is based on GIPSY scientific processing engine. The two approaches show an excellent agreement with less than 3 mm rms error horizontally and 6 mm rms error vertically. The derived position time series is analysed in terms of trend, periodicity and noise characteristics. The noise of the time series was found to be power-law noise model with spectral index closer to flicker noise. In addition, several periodic signals were found at 5, 14, 183 and 362 days. Furthermore, most of the horizontal movement was found to be in the North direction at a rate of 11.23 ± 0.09 mm/y, whereas the rate in the East direction was estimated to be 1.46 ± 0.05 mm/y. Lastly, the 15-year long time series revealed a movement upwards at a rate of 0.79 ± 0.35 mm/y. Despite being an unattended station, Aboa provides one of the most continuous and longest GPS time series in Antarctica. Therefore, we believe that this research increases the awareness of local geophysical phenomena in a less reported area of the Antarctic continent.

Postglacial rebound in Fennoscandia causes striking trends in gravity measurements of the area. We present time series of absolute gravity data collected between 1976 and 2019 on 12 stations in Finland with different types of instruments. First, we determine the trends at each station and analyse the effect of the instrument types. We estimate, for example, an offset of 6.8 μgal for the JILAg-5 instrument with respect to the FG5-type instruments. Applying the offsets in the trend analysis strengthens the trends being in good agreement with the NKG2016LU_gdot model of gravity change. Trends of seven stations were found robust and were used to analyse the stabilization of the trends in time and to determine the relationship between gravity change rates and land uplift rates as measured with global navigation satellite systems (GNSS) as well as from the NKG2016LU_abs land uplift model. Trends calculated from combined and offset-corrected measurements of JILAg-5- and FG5-type instruments stabilized in 15 to 20 years and at some stations even faster. The trends of FG5-type instrument data alone stabilized generally within 10 years. The ratio between gravity change rates and vertical rates from different data sets yields values between − 0.206 ± 0.017 and − 0.227 ± 0.024 µGal/mm and axis intercept values between 0.248 ± 0.089 and 0.335 ± 0.136 µGal/yr. These values are larger than previous estimates for Fennoscandia.

The regional key comparison of absolute gravimeters, EURAMET.M.G-K3 and the simultaneously organized additional comparison, was held in Germany at the Geodetic Observatory Wettzell of the German Federal Agency for Cartography and Geodesy in the spring of 2018. Here we present the list of the participants who actually performed measurements during the comparison, the data submitted by the operators as well as the results of the determination of the gravity as a function of height at the comparison sites. The measurement strategy is briefly discussed and the results of the data harmonization is documented. Finally, the results of the constrained least squares adjustment are presented including the degrees of equivalence of each gravimeter and the key comparison reference values.

This study investigates the effects of non-tidal atmospheric loading on GNSS time series for a network covering the Nordic countries, with a specific focus on Finland. We processed a 5-month dataset from the year 2015 using GAMIT/GLOBK software, implementing two distinct non-tidal atmospheric loading grid models, namely ‘atmfilt’ and ‘atmdisp’. Our results reveal that both grid models yield similar improvements in the variability of GNSS coordinate time series, albeit with a slightly better performance for ‘atmdisp’ grid. Our results show that implementing these built-in models in the time series analysis yields up to a 14% improvement (reduction in scatter) in the vertical component for 75% of the selected stations. However, the enhancement diminishes for the horizontal components (increase in scatter), exacerbating the eastern component of time series. The corrections lead to a 10% improvement of the North component. We also examined the effectiveness of the loading corrections by comparing our processing-level corrected time series to the daily averaged time series improved by the loading model provided by EOST loading service as a post-processing approach. Given the relatively short 5-month duration of the time series, drawing definitive conclusions when comparing models is challenging. However, it is evident that the GNSS time series exhibits distinct variations related to atmospheric loading in their vertical positions across the various models that were examined.

We report on establishing the mobile Finnish Seismic Instrument Pool (FINNSIP) that is owned and operated by Finnish academic and research institutions. The pool supports domestic and international collaborative seismic research. At the conclusion of the 2020 to 2024 build-up stage, the instrumentation includes 46 broadband seismometers and digitizers, 5 accelerometers, and 1216 and 71 Geospace and SmartSolo autonomous geophone units, respectively, making FINNSIP one of the largest and most coherent mobile seismic instrument pools in Europe in the public sector. We explain the utilization of the pool instruments and discuss the equipment, facilities, ownership and governance structure, fees, and the management and support system. Through Finland's membership in the Observatories and Research Facilities for European Seismology (ORFEUS) and the Finnish European Plate Observing System (EPOS) node, FINNSIP endorses and implements international data management standards and best practices as promoted in Europe. The importance of appropriate data and computing systems is highlighted by the ~90 TB volume of formatted data that has been collected in 25 large-N projects between October 2021 and December 2024. We summarize a checklist for building, operating, and managing this extensive seismic pool that can inform the planning and establishment of other research infrastructure.

Validation of GNSS-based reference point monitoring of the VGOS VLBI telescope at Metsähovi