Quantifying vertical land motion at tide gauge sites using permanent scatterer interferometric synthetic aperture radar and global navigation satellite system solutions

Abstract

One of the consequences of climate change is sea level rise (SLR). Near the coast SLR varies at different locations due to the contributions from regional/local climatic and non-climatic factors. Vertical land motion (VLM) can affect the accuracy of sea level observations from tide gauges (TG) that may exacerbate coastal area inundation/flooding. This study investigated the viability of Permanent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) to quantify the rate of VLM at the TG sites. Measurements from TG co-located GNSS receivers provide the actual VLM rates and ground truth for PSInSAR-derived rates. Based on the results from the 9 study sites, almost all except one are subsiding. Both PSInSAR and GNSS solutions showed the same trend with rates that correlate at 0.89. Analysis from 20 Active GNSS stations showed 95% of the sites are undergoing land subsidence. This should be a cause of concern for communities near the coastal areas.