Exploring the influence of climate oscillations on groundwater: Review of observational studies

Groundwater is critical for society’s adaptation to climate variability and change but simultaneously, is threatened by them. This paper reviews the linkages between climate oscillations and groundwater, focusing on studies reported in the Scopus database that use wavelet analysis. A total of 27 records published since 2009, covering North America, Europe, and Asia, have been analysed. El Niño Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), Arctic Oscillation, and the Pacific Decadal Oscillation (PDO) show important effects on groundwater levels in North America. In Europe, NAO is the most dominant, while in Asia, distinct climate indices impact groundwater levels at different periodicities. The hydrogeological features of the aquifers condition the magnitude of the response of groundwater to the climate signal and there is conflicting evidence concerning the effects of land-use change and human activities on detecting climate signals in aquifers. Further research must focus on understanding the effect of human activities in the climate signal perception in aquifers, unravelling the physical mechanisms underlying the propagation of climate signals through aquifers, developing predictive models to support water management decisions, and finding alternative methods to assess this influence in regions with limited observational data. The interaction between the atmosphere and groundwater is of critical relevance for the achievement of water security and this review contributes to synthesizing our current understanding of this relationship.