On the isotopic composition of precipitation in tropical stations (*).

Some of the trends and characteristics of the isotopic composition oh precipitation in tropical stations are discussed. Stations in small Pacific islands show a variation with latitude, with lower 8-values between 15°N and 1S°S and higher values at higher. Inland stations are depleted in heavy isotopes with respect to coastal stations but sometimes this continental effect is rather complex, as f,or instance in África. Mean monthly 8-values show a remarkable correlation with the amount of precipitation, but the slope variations do not show a clear dependence on the mean long term 8-value,as should be expected theoretically. In Southern American stations the seasonal variations of the meanmonthly 5-values are correlated and they are greater in inland stations due to con-tinentaly. The possible effects of recycling of water vapour by evapotranspiration are also discussed

Oxygen isotope variations in antarctic snow samples

THE relative abundance of oxygen isotopes in atmospheric precipitation being closely related to temperature, it has been suggested that the variations of the ratio oxygen-18/oxygen-16 in snow should be used in glaciological studies of polar regions1,2. It has been recently announced that very promising results have been already obtained by analysing cores of old ice from deep bore holes in Greenland3. © 1959 Nature Publishing Group.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Intercalibration of Environmental Isotope Measurements: The Program of the International Atomic Energy Agency

From the International Workshop on Intercomparison of Radiocarbon Laboratories.We briefly present here the environmental isotope intercalibration programs of the International Atomic Energy Agency (IAEA). In fact, the IAEA has implemented two parallel programs during the last 20 years: for stable isotopes of light elements and for a radioactive isotope of hydrogen, tritium. This IAEA activity resulted in the preparation of a number of reference and intercomparison materials of various types, now stored in the Agency and available upon request.This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Jean-Charles Fontes (3 November 1936 – 2 February 1994)

This material was digitized as part of a cooperative project between Radiocarbon and the University of Arizona Libraries.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Adsorption in Gas Mass Spectrometry - I. Effects on the Measurement of Individual Isotopic Species.

Abstract not availableJRC.D-Institute for Reference Materials and Measurements (Geel

Isotopic variations during precipitation. Application of the Rayleigh model to selected rainfalls in Avignon, France.

International audienc

Using Isotopic Disequilibrium of CO2 to Model Gas Adsorption in Mass Spectrometric Measurements.

Measurements carried out on a CO2 sample prepared by mixing known amounts of natural CO2 with CO2, enriched in 13-C and, to a lesser extent, in 17-O and 18-O, revealed that the mixture was not in isotopic equilibrium. This occurs for samples of any gas containing more than one isotopically exchangeable atom in the molecule, prepared by mixing gases with different isotopic composition. As a consequence, it was impossible to derive the mean isotope ratios from the measurement because the equations normally used for data reduction assume that isotopic equilibrium takes place, i.e. the isotopic species distribution obeys the statistical probability.JRC.D-Institute for Reference Materials and Measurements (Geel