INGEIS   05370
INSTITUTO DE GEOCRONOLOGIA Y GEOLOGIA ISOTOPICA
Unidad Ejecutora - UE
artículos
Título:
Large scale meteorological phenomena, ENSO and ITCZ, define the Paraná River isotope composition
Autor/es:
PANARELLO, H.O.; DAPEÑA, C.
Revista:
JOURNAL OF HYDROLOGY
Editorial:
ELSEVIER
Referencias:
Lugar: Amsterdam, Holanda; Año: 2009 vol. 365 p. 105 - 112
ISSN:
0022-1694
Resumen:
The Paraná River, the second in discharge in South America after the Amazon River and the fifth all over the world, releases an average of more than 17000 m3 /s into the Del Plata Estuary. In order to assess the causes of variations in its stable isotope composition, 120 monthly grab samples of the Paraná River, acquired on a period of 10 years at the river mouth, near Ciudad Universitaria, Buenos Aires, Argentina have been analysed for oxygen and hydrogen stable isotopes. Both, 2H and 18O showed periodic variations (delta18O between -7‰and -3‰; delta2H between -44‰and -15‰) that follow, shifted in ca. 4 months (average transit time of the river), the southward excursions of the intertropical convergence zone (ITCZ). Deuterium excess values (delta2H - 8delta18O) also exhibited large variations (3–18‰) and showed a positive correlation with the El Niño South Oscillation Phenomenon (ENSO) index. ENSO affects the kinetic of the evaporation process of water and modifies the degree in which ITCZ shifts southwards capturing variable amounts of deuterium-rich recycled moisture from the Amazon’s basin, then precipitating on the catchment’s areas of the Paraná River.