The goal of Work package 1.1 is to measure and monitor subsidence at high spatio-temporal resolutions by using the latest generation satellite-based Synthetic Aperture Radar (SAR) technology. We will use data from the following missions: Sentinel-1, Radarsat-2 and TerraSAR-X. A key goal is to develop processing workflows and algorithms to process regularly incoming SAR data and produce up-to-date ground subsidence estimates. This relies on iteratively computing InSAR coherence matrices for interferometric combinations, and collapse these to an equivalent single-master stack holding the temporal subsidence estimates.
One key issue to overcome is that SAR data over agricultural and nature-restoration areas suffers from temporal decorrelation, seriously hindering the use of conventional SAR for subsidence monitoring. This will be countered by (i) informing the algorithms with spatially accurate terrain and land-use status information, and (ii) deploying ground-based reflectors and transponders. With such information, the phase estimation (fundamental in interferometry) over these areas can be improved relative to conventional processing (as pilot studies have shown).
To verify and validate the remote-sensing measurements, data collected on the ground is used (case study site visits, plot and field scale subsidence measurements, geotechnical insights; synergy with WP2-3-4 approaches).
From a related project with other funding (Regiodeal Groene Hart), PhD candidate is also connected to WP1.1 is Simon van Diepen.