Surface Mass Balance Loading in Antarctica 1979 - 2022

The purpose of this study is to evaluate performance of seven different SMB estimates by using GPS vertical deformation timeseries. Data contain the information on elastic displacements at GPS sties in Antarctica from 1979 to 2022, derived from seven SMB products namely RACMO2.4p1 (11 km spatial resolution, monthly temporal resolution), RACMO2.3p2 (27 km, monthly), a downscaled version of RACMO2.3p2 (2 km, monthly), MAR v3.11 (35 km, monthly), GEMB (10 km, monthly), HIRHAM5 (12.5 km, monthly) and MERRA-2 (12.5 km, 5 days). We generated the SMB mass variability time series spanning 1980-2022 by first computing, for each SMB model, the SMB anomalies from the long-term mean SMB computed over 1980-2022. The resulting SMB anomalies were cumulatively summed, detrended, and bilinearly interpolated onto a common regular grid of 2 km resolution. A uniform land mask (Mosaic of Antarctica version 2), defining the extent of the grounded ice sheet (including the offshore islands), was applied to the grid after resampling to the same 2 km resolution. We computed elastic displacements derived from each of these SMB models by converting the detrended SMB mass anomalies at each location and time into arrays of cylinders defined with 1 km radius and a height representing the equivalent ice mass. These arrays were subsequently input into the Regional ElAstic Rebound calculator (REAR, v1.5), adopting the Preliminary Reference Earth Model (PREM) to compute the elastic loading displacements in a centre-of-solid Earth (CE) reference frame at each GPS site location.