Factors that control the isotopic composition of precipitation in northern Chile

The determination of aquifer recharge zones is necessary for optimal and sustainable management of water resources. Stable isotopes (δ¹⁸O and δ²H) are an effective tool to better understand the relationship between precipitation and groundwater. However, there are areas in the world such as northern Chile, where there is a lot of available isotopic information on groundwater but very heterogeneous isotopic information on precipitation. This study contributes to a better understanding of the spatial and meteorological variables that control the isotopic composition in precipitation in Northern Chile and to estimate these meteorological and stable isotopes in precipitation. Results show that in summer, the significant features for temperature, relative humidity and precipitation are altitude-latitude, latitude and altitude-latitude respectively. The stable isotopes of precipitation are controlled by temperature, altitude, latitude, longitude, and precipitation. The monthly estimation models of temperature, relative humidity and precipitation and three isotopic models (summer, winter and annual) are created based on the controlling features.