Controls over spatial and seasonal variations on isotopic composition of the precipitation along the central and eastern portion of Brazil

• Published in: Isotopes in environmental and health studies 2017-10, Vol.53 (5), p.518-538
• Main Authors: Gastmans, Didier, Santos, Vinícius, Galhardi, Juliana Aparecida, Gromboni, João Felipe, Batista, Ludmila Vianna, Miotlinski, Konrad, Chang, Hung Kiang, Govone, José Silvio
• Format: Article
• Language: English
• Subjects: Air Movements; Brazil; Brazilian climate; Composition effects; Convergence zones; Deuterium; deuterium excess; Environmental Monitoring; hydrogen-2; Hydrologic data; isotope hydrology; Isotopes; Meteorological parameters; Multiple regression analysis; multiple regression model; Oxygen Isotopes; oxygen-18; Precipitation; Rain; Rainfall; Rainforests; Regression analysis; Seasonal variations; Seasons; Spatial distribution; Stable isotopes; Temporal variations; Variability
• ISSN: 1025-6016; 1477-2639
• DOI: 10.1080/10256016.2017.1305376

Based on Global Network Isotopes in Precipitation (GNIP) isotopic data set, a review of the spatial and temporal variability of δ 18 O and δ 2 H in precipitation was conducted throughout central and eastern Brazil, indicating that dynamic interactions between Intertropical and South Atlantic Convergence Zones, Amazon rainforest, and Atlantic Ocean determine the variations on the isotopic composition of precipitation over this area. Despite the seasonality and latitude effects observed, a fair correlation with precipitation amount was found. In addition, Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) air mass back trajectories were used to quantify the factors controlling daily variability in stable isotopes in precipitation. Through a linear multiple regression analysis, it was observed that temporal variations were consistent with the meteorological parameters derived from HYSPLIT, particularly precipitation amount along the trajectory and mix depth, but are not dependent on vapour residence time in the atmosphere. These findings also indicate the importance of convective systems to control the isotopic composition of precipitation in tropical and subtropical regions.