The main aim of the article was to analyse the actual accuracy of determining the vertical movements of the Earth’s crust (VMEC) based on time series made of four measurement techniques: satellite altimetry (SA), tide gauges (TG), fixed GNSS stations and radar interferometry. A relatively new issue is the use of the persistent scatterer InSAR (PSInSAR) time series to determine VMEC. To compare the PSInSAR results with GNSS, an innovative procedure was developed: the workflow of determining the value of VMEC velocities in GNSS stations based on InSAR data. In our article, we have compiled 110 interferograms for ascending satellites and 111 interferograms for descending satellites along the European coast for each of the selected 27 GNSS stations, which is over 5000 interferograms. This allowed us to create time series of unprecedented time, very similar to the time resolution of time series from GNSS stations. As a result, we found that the obtained accuracies of the VMEC determined from the PSInSAR are similar to those obtained from the GNSS time series. We have shown that the VMEC around GNSS stations determined by other techniques are not the same.
Abstract. Data reduction is a procedure to decrease the dataset in order to make their analysis more effective and easier. Reduction of the dataset is an issue that requires proper planning, so after reduction it meets all the user's expectations. Evidently, it is better if the result is an optimal solution in terms of adopted criteria. Within reduction methods, which provide the optimal solution there is the Optimum Dataset method (OptD) proposed by Błaszczak-Bąk (2016). The paper presents the application of this method for different datasets from LiDAR and the possibility of using the method for various purposes of the study. The following reduced datasets were presented: (a) measurement of Sielska street in Olsztyn (Airbrone Laser Scanning data -ALS data), (b) measurement of the bas-relief that is on the building in Gdańsk (Terrestrial Laser Scanning data -TLS data), (c) dataset from Biebrza river measurment (TLS data).
The paper presents an analysis of the possibilities of using a data set of Sentinel-1 (S-1) Interferometric Synthetic Aperture Radar (InSAR) for urban monitoring. The study was conducted in the Olsztyn area, where by using the PSI (Persistent Scatterer InSAR) method the amount of deformation was determined, calculated using a multi-time SAR data series. Displacement values were estimated by reducing error sources related to temporal and geometrical decorrelation and atmospheric phase delay. Based on the defined assumptions, three calculation cases were prepared. This processing is based on the data from more than 648 Sentinel-1A/B images over ascending and descending orbits acquired between October 2014 and August 2018 to determine the value of the Line of Sight (LOS) ground deformation rates. Regular acquisition of SAR images from the Sentinel-1 satellite sensor in an interval of 2 days enabled the detection of more than 1000 PSI points per 1 km 2 in the 10 × 10 km 2 urban area. The mean LOS velocity of surface change was determined on the basis of four large data sets. Comparable values were obtained from ascending tracks 29, 102 and descending tracks 51, 124 where mean velocity ranges respectively: A29 from -4.3 to 3.4 mm/yr, A102 from -3.9 to 3.5 mm/yr and D51 from -3.9 to 3.1 mm/yr, D124 from -3.8 to 3.2 mm/yr. Then the results of geometries were combined in pairs to compute the actual vertical motion component. In the presented work, an analysis of the terrain deformation was performed for selected characteristic objects located within the Olsztyn area. In the first case study, a detailed analysis of urban infrastructure facilities was carried out, including buildings and a section of the railway line. The other case study covers an area along the river bank. A large number of observations allowed to accurately determine the deformation model and to produce the history of deformations on the tested area, based on the analysis of time series of interferograms. The paper presents solutions using InSAR data in urban monitoring and shows why this technology is a useful tool for studying measuring urban subsidence. The results are displayed in the form of a deformation map showing the magnitude of the measured movement.
The analysis of changes in the level of air pollution concentration allows for the control of air quality and its compliance with the normative requirements. Currently, every country in Europe implements air quality monitoring. However, during emergencies in areas that are often difficult to monitor, the only source of information is geospatial data obtained by means of Earth observation techniques. The aims of this study were to estimate the amounts of pollutant concentrations and develop a pattern of spatiotemporal changes in Central and Eastern Europe in Poland and Ukraine. Due to the ongoing military operations in Ukraine, it is an area that is difficult to access. Pollution from industrial facilities, fires, collapsed buildings, and the use of explosive weapons poses a threat to air quality. Additionally, the impact of war on air pollution concentration levels remains unclear. This work characterized the changes in the distribution of sulfur dioxide, nitrogen dioxide and carbon monoxide concentrations in 2018–2022 in local zones in both countries. Publicly available TROPOMI-S5 satellite data were used for this study, which were compared with measurements from ground stations in Poland. It has been estimated that the concentration of NO2 (+0.67 ± 0.47 µmol/m2) in Poland has increased and the level of SO2 and CO have decreased in both studied areas: in Poland (−161.67 ± 5.48 µmol/m2, −470.85 ± 82.81 µmol/m2) and in Ukraine (−32.56 ± 23.51 µmol/m2, −438.04 ± 80.76 µmol/m2). The concentration of NO2 in Ukraine has decreased by −0.28 ± 0.21 µmol/m2.
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