Persistent Scatterer Time Series Analysis of Subsidence in the Tampa Bay Region

Coastal subsidence is increasingly recognized as a risk factor for coastal flooding, adding to the effects of sea level rise. Natural compaction of young sediments, and anthropogenic processes such as fluid withdrawal, compaction of newly dredged sediments for land reclamation projects, and oxidation of carbon-rich organic soils after drainage, may all contribute. We used Sentinel 1A synthetic aperture radar (SAR) satellite data and the persistent scatterer interferometric (PSI) technique to investigate the spatial and temporal patterns of subsidence in the Tampa Bay region. 154 images SAR images collected between April 17, 2016, and January 28, 2022, were analyzed with the Stanford Method of Persistent Scatterer (StaMPS). The Generic Atmospheric Correction Online Service for InSAR (GACOS) model was used to minimize atmospheric effects. Assuming the center of the Pinellas Peninsula is stable, line-of-site (LOS) changes imply subsidence rates of some near-coast regions as high as 3 mm/yr, comparable to the global average rate of sea level rise. Preliminary analysis suggests groundwater extraction is not a significant factor in this subsidence since major well fields are located north of coastal regions showing the highest subsidence rates. However, areas further inland experiencing high 3 mm/yr subsidence correlate to mining and agricultural practices.