APPLICATION OF ENVIRONMENTAL ISOTOPETECHNIQUES TO SELECTED HYDROLOGICALSYSTEMS IN PAMPEAN, ARGENTINA

摘要

The isotopic composition of precipitation in Buenos Aires station is of greatimportance to understand the Pampean hydrological Systems. The rain isotopecontent ( 2 H, 18 O and 3 H) is being recorded since 1978 at Ciudad Universitaria Station,belonging to the Red Nacional de Colectores constitutes the main rechargefactor for most of local and regional hydrologic system. The knowledge andcharacterization of their isotope content is of fundamental importance for ahydrological investigation, so we need a historical updated record. For thisreason the International Atomic Energy Agency (IAEA) in co-operation withthe World Meteorological Organization (WMO) developed an internationalnetwork devoted to the measurement of isotope contents in precipitationnamed as GNIP (Global Network for Isotopes in Precipitation) which startedin 1960. The main objective of the network is to evaluate on a global scale thespatial and temporal distribution of isotope contents in precipitation and theirdependence to relevant meteorological parameters [1]. In this framework,the “Instituto de Geocronología y Geología Isotópica” (INGEIS) establisheda National Collector Network for Isotopes in Precipitation (RNC) whichintegrates with the GNIP. The operation of the network in Argentina beganin November 1978 with one station located in Buenos Aires City. At present,INGEIS is operating 17 stations at different altitudes and latitudes, coveringa wide range of temperatures and a large variety of climates. This informationallows us to know the input functions (rain isotope content) at different regionsof the country [2].Signatures of isotopes in precipitation are not static. They respond to both,synoptic and climatology and global climate change. Attracted by this issue,a new community, interested in palaeoclimate and atmospheric circulationmodelling, started to use the GNIP data. However, it becomes apparent soonthat the collected data were also useful in other water-related fields such asoceanography, hydrometeorology and climatology. The meteorological analysis