Performance analysis of the Atmospheric Phase Screen filtering approach of the Parallel Small BAseline Subset DInSAR technique

One of the main challenges for correctly retrieving Earth surface deformation measurements from DInSAR products is the presence of the so called Atmospheric Phase Screen (APS) signals. Indeed, such atmosphere-induced delay components can be easily confused with those related to deformation. Therefore, it can be challenging to discriminate atmospheric artifacts and deformation patterns and, therefore, to properly filter out the APS signals from the DInSAR products.

In this work we investigate the performance of the APS filtering approach implemented within the Parallel Small BAseline Subset (P-SBAS) technique [1], which exploits external Numerical Weather Model (NWM) data, in particular the ECMWF ERA-5 ones, and DInSAR data-driven methodologies.

The applied approach consists of various filtering steps for the removal of different atmospheric phase contributions. In particular, as a first step, for the estimation and removal of the topography-related atmospheric phase component, we compare the effectiveness of two solutions. The former uses the quasi-linear phase-elevation relationship to estimate the APS stratified component from the DInSAR data. The latter makes use of the ERA-5 data, which are particularly effective in mitigating the atmospheric contributions correlated with the height [2]. Then, we analyze the impact of the iterative spatial filtering step used to estimate the spatially-correlated atmospheric components at different spatial scales. Finally, we investigate the effectiveness of the final temporal filtering step allowing us to mitigate the residual high-frequency atmospheric signals.

For the experimental analysis, we have exploited the overall S1 images dataset acquired along ascending and descending orbits over Italy, during the 2016-2024 time-span.

 

ACKNOWLEDGMENT

This research was partially funded by the European Union - NextGeneratonEU program through the following projects: ICSC - CN-HPC - PNRR M4C2 Investimento 1.4 - CN00000013, GeoSciences IR - PNRR M4C2 Investimento 3.1 - IR0000037, and by the Italian DPC, in the frame of the IREA-DPC (2022–2024) agreements, and by the Geo-INQUIRE and SAR-L: Consolidamento della Scienza projects. The activities were also partially funded by the European Union - NextGeneratonEU SMUH PRIN 2022 project (2022M7W3BM). This study was supported by the GRINT (PIR01_00013) and IBiSCo (PIR01_00011) projects, funded by the National Operational Programme Infrastructures and Networks 2014/2020 of the Italian Ministry of Infrastructure and Transports.

 

REFERENCES

[1] M. Manunta et al., "The parallel SBAS approach for Sentinel-1 interferometric wide swath deformation time-series generation: Algorithm description and products quality assessment," IEEE Transactions on Geoscience and Remote Sensing, vol. 57, no. 9, pp. 6259-6281, 2019.

[2] I. Zinno, F. Casamento and R. Lanari, "On the Exploitation of the ETAD Product for Filtering Out the Atmospheric Phase Screen From Medium Resolution DInSAR Measurements: An Extensive Performance Analysis," in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, vol. 18, pp. 712-727, 2025.