Laurentia Glacial Isostatic Adjustment Observed From GRACE and Satellite Altimetry

The use of satellite radar altimetry to detect solid Earth deformation signals such as the Glacial Isostatic Adjustment (GIA) has been demonstrated by Lee et al. (2007) observing the Laurentia GIA signals using TOPEX (1992-2002) over the Hudson Bay land region. GRACE gravimetry, despite of its short data record (2002-present), confirmed the presence of two Pleistocene ice domes near the east and west of Hudson Bay manifested in the incomplete GIA in Laurentia (Tamisiea et al., 2007). In this study, we densify land uplift measurements over the Hudson Bay land region by developing 10-Hz stackfile from TOPEX (1992-2002), and by combining altimetry measurements and long-term water level records (Kuo et al., 2007) for data over small lakes. Here we use GRACE observations of Hudson Bay land region uplift, including the use of spherical harmonic and regional solutions (spherical wavelet solutions directly using L1B KBR data), radial GIA models (ICE4G, ICE5G, BIFROST), and 3-D laterally heterogeneous GIA model (RF3S20), and satellite altimetry observed deformation rates, to study potential constraints on the Pleistocene GIA process over Laurentia, including ice modeling and Earth rheology.