Groundwater is recognized as the primary source of water supply in arid and semi-arid regions. The Central Plateau of Iran is one of the most critical regions of the country in terms of water resources, experiencing a severe decline in groundwater levels due to low precipitation, high evapotranspiration, and excessive groundwater abstraction. Under such conditions, quantitative estimation of groundwater recharge and understanding its spatiotemporal variability are essential components of sustainable water resources management.

Despite its importance, regional-scale groundwater recharge estimation is associated with considerable uncertainty due to the limited availability of in situ data and the uneven spatial distribution of meteorological and piezometric stations. Recent advances in remote sensing data, particularly GRACE satellite observations and atmospheric reanalysis products such as ERA5-Land, have enabled the monitoring of terrestrial water storage changes and water balance components at large spatial scales. The objective of this study is to quantitatively estimate and analyze the spatiotemporal patterns of annual groundwater recharge in the Central Plateau of Iran by integrating GRACE, ERA5-Land, and ground-based observations, and to evaluate the applicability of these datasets for long-term groundwater monitoring in arid regions.