Potential groundwater recharge estimates in the Yucatan Peninsula using gridded data products & parsimonious water balance models

Study region The Yucatan Peninsula (YP) and its unconfined aquifer, covering a surface of almost 150,000 km 2 and being the only terrestrial freshwater source for human activities and ecosystems. Study focus This research work aims at characterizing potential groundwater recharge rates at the Yucatan Peninsula (Mexico), one of the world's largest karstic aquifer systems by means of reanalysis, satellite and data assimilation products. Gridded precipitation, evapotranspiration and spaceborne-derived gravimetry water storage variation products were applied whereas ground climatological data and previous recharge estimates were used for validation. These 10 datasets were tested over 21 different input combinations and 4 water balance methods (Budyko dimensionless & functional equations, simple water and gravimetry-based balance). New hydrological insights for the region Results suggest that the long-term annual potential recharge across the Yucatan Peninsula varied between 169 and 222 mm/year according to the first, third and fourth methods whereas the second method provided higher recharge rates. The precipitation and evapotranspiration data products that better mimicked the long-term recharge rates were CHIRPS & GLDAS/TerraClimate, respectively. We conclude that (1) five out of twenty-one gridded input combinations were reliable estimators of mean annual groundwater recharge (2) simple water balance models are useful groundwater balance studies in this karstic region largely dominated by subsurface storage (3) Interannual variability of recharge from cyclonic precipitation events are well represented according to our models’ behavior.