Contribución Preliminar a la interpretación del origen de las lluvias en el Norte de Argentina.

DAPEÑA, CRISTINA; PANARELLO, HECTOR; CERNE, BIBIANA; GONZALEZ, MARCELA; SANCHEZ-CCOYLLO, ODON

Río Cuarto, provincia de Córdoba

Congreso; IV Congreso Hidrogeológico Argentino y II Seminario Hispano Latinoamericano sobre Temas actuales de Hidrología Subterránea; 2005

Grupo Argentino Asociación Internacional de Hidrogeología, Departamento de Geología de la Facultad de Ciencias Exactas, Fisico-Químicas y Naturales y Universidad de Río Cuarto

The isotopic composition of precipitation is of great importance to understand theinterpretation of the hydrologic systems. Rainfall is the main recharge mechanism so theevaluation of the spatial and temporal distribution of isotope contents in precipitation andtheir dependence on relevant meteorological parameters provide basic input data.Investigations concerning the sources of vapour in the Argentina subtropical are scarce: airoceanic trajectory induced by the Atlantic Anticyclone which transport vapour to the continentand in summer, the north humid wind, which pass through the Amazonian forest (Low LevelJet -LLJ). During summer 2002-2003 SALLJEX (South American Low Level Jet Experiment)experiment was performed to study tri-dimensional LLJ structure and its atmospheric relatedfeatures. Daily rainfall water samples were collected in Resistencia and Salta stations.Isotope analysis showed a good correspondence with the meteoric water line. It is a usefultool to infer if rainfall in both locations was originated in air masses with similar features.Dataset is scarce but results show that the 18O and deuterium excess in rainfall water seemto be related to the Low Level Jet occurrence. This result lets give importance to long termand daily measurements of rainfall isotopic content in Argentina. To estimate the track of theair masses and to analyse the sample isotope content, a trajectory analysis was used.