Observing glacial isostatic adjustment by PSInSAR in southern Hudson Bay

Glacial isostatic adjustment (GIA) is the solid Earth's viscoelastic response to ice sheet deglaciations. Studies of GIA provide insights into crustal and mantle rheology, mass redistribution, relative paleo sea-level variations, and polar wander. In North America, GIA causes large-scale and low-gradient vertical displacement, but limited ground-based measurements in some places hinder accurate detection of such signals. This study proposes a workflow to extract GIA-induced land deformation using interferometric synthetic aperture radar (InSAR) time-series over the southern Hudson Bay land region. The workflow incorporates several model-based corrections to account for multiple elastic lithospheric responses and atmospheric phase disturbances, significantly reducing variances in the estimated time-series. It further separates the GIA signals from residual short-period noise through a spatiotemporal filter, as demonstrated in variogram analyses. With the workflow we produced the first high-resolution InSAR-based GIA vertical velocity map in the southern Hudson Bay land area at an estimated uncertainty of 2 mm/yr. Our result exhibits first-order agreement with contemporary GIA model predictions, and suggests that higher-level complexities such as 3D rheology structures or spatially uneven loading dynamics may exist in this region.