Monthly 0.5°groundwater storage change in Africa from 2003 to 2020 (GWS-AF05_2003-2020)

The monitoring objective of this data product is the groundwater storage change, which refers to the monthly anomaly relative to the 2003–2020 mean and is expressed in equivalent water height (unit: mm). The data used are spherical harmonic coefficients from GRACE (Gravity Recovery and Climate Experiment), GRACE Follow-On and model simulations from CLSM (Community Land Surface Model) v2.2. The data were produced using the coordinated forward modeling (CoFM) method, which uses model simulations to constrain the GRACE mass change signal to reduce bias and leakage errors at grid scale. These errors were then corrected by the CoFM through iteratively updating the aquifer storage coefficients, which were finally used together with the simulated groundwater levels to estimate the monthly groundwater storage change at a 0.5°grid scale.