Neves, Maria C.Moreira, ElsaCosta, Luis2025-03-052025-03-052023-12-01http://hdl.handle.net/10400.1/26848Groundwater drought presents significant economic and societal challenges, highlighting the need for effective monitoring and early warning systems at local and regional scales. Despite its vital role in water supply and irrigation, groundwater drought is often not adequately monitored in national operational systems. While the propagation of meteorological drought through hydrological systems has been extensively studied in various parts of the world, there is a lack of groundwater drought monitoring at an integrated basin-scale based on groundwater data. Long-term hydrological drought is often assessed using meteorological drought indices like SPI or SPEI with long periods of accumulation (12, 24 or 48 months time scales). However, most studies recognize that the accumulation periods necessary to achieve maximum correlation with groundwater observations exhibit high spatial variability due to the complexity of local hydrogeological conditions. This study aims to address this gap on groundwater drought monitoring in the Algarve by investigating the suitability of GRACE-based drought indices and ground-based drought indices derived from piezometer measurements for monitoring and predicting groundwater droughts.engconference object2025-03-03cv-prod-4395611