Impact of climate indicators on continental‐scale potential groundwater recharge in Africa

Abstract

In the last decades, human activity has been contributing to climate change that is closely associated with an increase in temperatures, increase in evaporation, intensification of extreme dry and wet rainfall events, and widespread melting of snow and ice. Understanding the intricate linkage between climate warming and the hydrological cycle is crucial for sustainable management of groundwater resources, especially in a vulnerable continent like Africa. This study investigates the relationship between climate-change drivers and potential groundwater recharge (PGR) patterns across Africa for a long-term record . Water-balance components were simulated by using the PCR-GLOBWB model and were reproduced in both gridded maps and latitudinal trends that vary in space with minima on the Tropics and maxima around the Equator. Statistical correlations between temperature, storm occurrences, drought, and PGR were examined in six climatic regions of Africa.Surprisingly, different effects of climate-change controls on PGR were detected as a function of latitude in the last three decades . Temporal trends observed in the Northern Hemisphere of Africa reveal that the increase in temperature is significantly correlated to the decline of PGR, especially in the Northern Equatorial Africa. The climate indicators considered in this study were unable to explain the alarming negative trend of PGR observed in the Sahelian region, even though the Standardized Precipitation-Evapotranspiration Index (SPEI) values report a 15% drought stress.On the other hand, increases in temperature have not been detected in the Southern Hemisphere of Africa, where increasing frequency of storm occurrences determine a rise of PGR, particularly in southern Africa. Time analysis highlights a strong seasonality effect while PGR is in-phase with rainfall patterns in the summer (Northern Hemisphere) and winter (Southern Hemisphere) and out-ofphase during the fall season. This study helps to elucidate the mechanism of the processes influencing groundwater resources in six climatic zones of Africa, even though modeling results need to be validated more extensively with direct measurements in future studies.

Assessment of the impact of rainfall uncertainties on the groundwater recharge estimations of the Tikur-Wuha watershed, rift valley lakes basin, Ethiopia

“…Spatial recharge estimation uncertainty is directly proportional to the uncertainty in precipitation data used in the estimation process [ 7 , 10 , 11 ]. The statistical characteristics of rainfall and reference evapotranspiration dataset used in recharge estimation were studied by Turkeltaub and Bel (2023) for the semiarid climate regions in China and Israel [ 12 ].…”

The effects of rain and evapotranspiration statistics on groundwater recharge estimations for semi-arid environments

“…Rainfall characteristics such as total amount, intensity, and frequency are important climate factors that strongly influence groundwater recharge (GR) rates (Small, 2005;Nasta et al, 2016;Barron et al, 2012). Understanding the effects of climate variables on the GR is essential for both a fundamental understanding of the physical processes and for the groundwater management under future climate conditions.…”

The effects of rain and evapotranspiration statistics on groundwater recharge estimations under semi-arid environments

“…Rainfall characteristics such as total amount, intensity, and frequency, are important climate factors that strongly influence groundwater recharge (GR) rates (Small, 2005;Nasta et al, 2016;Barron et al, 2012). Various studies have illustrated that rain intensity is superior to the total annual rainfall in determining GR (e.g.…”