Deuterium and oxygen-18 isotope composition of precipitation and atmospheric moisture

The stable isotopes of oxygen and hydrogen incorporated in the water molecu le (O-18 and H-2) have become an important tool not only in Isotope Hydrolo gy, routinely applied to study the origin and dynamics of surface and groun dwaters, but also in studies related to atmospheric circulation and palaeoc limatic investigations. A proper understanding of the behaviour of these tr acers in the water cycle is required for a meaningful use of these tools in any of these disciplines. Our knowledge of the vertical distribution and t he factors controlling the stable isotope ratios of oxygen and hydrogen in atmospheric moisture derives from a limited number of observations and vert ical profiles in the atmosphere. An international programme jointly operate d by the International Atomic Energy Agency (IAEA) and the World Meteorolog ical Organization (WMO), and operational since 1961, has resulted in the de velopment of a dedicated database to monitor isotope ratios in precipitatio n in more than 500 meteorological stations world-wide. The main features of the spatial and temporal variations of stable isotope ratios of oxygen and hydrogen in precipitation and atmospheric moisture at the global scale are presented based on the analysis of limited data on water vapour, data obta ined by the Global Network for Isotopes in Precipitation (GNIP) and the few observations at high latitudes. Copyright (C) 2000 John Wiley & Sons, Ltd.