Continental-Scale Groundwater Storage Dynamics and Climate Variability Across Africa (2003–2025): Regional Divergence and Hydro-Climatic Regime Shifts
Year: 2026
Type: preprint
Abstract: Groundwater is Africa’s most important buffer against climate variability, yet its regional and continental response to climatic and anthropogenic drivers remains poorly quantified. The study integrates Gravity Recovery and Climate Experiment satellite gravimetry, Global Land Data Assimilation System land-surface model output, and surface water storage estimates in a mass-balance framework to derive the groundwater storage anomalies (GWSA), recharge, and discharge across Africa since 2003 on a common 0.25° regular grid, and to assess the GWSA response to precipitation, temperature, and ENSO to characterize its climate sensitivity. Results show that GWSA ranges from − 30.60 mm (North Africa) to 96.56 mm (West Africa) at an overall trend of 3.84 mm yr⁻¹ (precipitation 0.10 mm yr⁻¹). A formal structural break test identified a hydrodynamic shift in July 2020, with the GWAS trend rising from 2.59 to 5.74 mm yr⁻¹, coinciding with the onset of the 2020–2023 “triple-dip” La Niña. Recharge-to-precipitation ratio ranging from 11.0% to 21.5%, with regional GWSA trends of -0.78, 5.27, 5.12, 6.04, and 4.67 mm yr⁻¹ trend of GWSA for North, West, Middle, East, and South Africa, respectively. This recovery continues even during the 2020–2022 Horn of Africa drought, underscoring GWSA’s value as an indicator of climate and human influence, and the importance of regional variation for future water security assessments.
Source: Research Square
Authors: Grmay Kassa Brhane, Chuen-Fa Ni, Chian-Yi Liu
Institutions: Academia Sinica, National Central University
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7225632858