Atmospheric Circulation and Isotopic Composition of Precipitation in the Central Andes

Abstract:

Water is a human right but in some areas of the world, such as in the central Andes, the water demand for human activities and the conservation of ecosystems present a fragile balance. Therefore, it is necessary to design strategies for optimal and sustainable management of water resources in a sustainable natural and social environment. To achieve this objective, the analysis of water stable isotopes is a powerful tool for understanding the regional and the local hydrological cycle. The exhaustive review of the literature has allowed us to identify the different climatic phenomena that affect the central Andes in each season of the year and the isotopic variation in rainfall.

In summary, the isotopic composition of rainfall varies spatially and temporarily, depending on the climatic phenomena that originate the movement of air masses, their moisture content and the isotope fractionation processes that occur until precipitation falls. Despite the extensive literature, there is no consensus among specialists on which physical aspects (latitude, altitude, distance from the coast, amount of precipitation) or combination of local precipitation microphysics, source of moisture and cloud type play the dominant role in δ¹⁸O and δ²H contents in precipitation in the Western Cordillera. These characteristics in the isotopic composition of the precipitation help us to quantify and identify the recharge zones of the aquifers.