| Abstract |
Since the late 1940s, decisive improvements in mass-spectrometry techniques as well as the continuous advancements in science and technology have enabled precise measurements of natural abundances of deuterium and oxygen-18 isotopes (water tracers) in precipitation. The stable isotopes of hydrogen and oxygen incorporated in the water molecule (δ2H and δ18O) have become an important tool not only in isotope hydrology, applied routinely to study the origin and dynamics of surface and groundwater, but also related to atmospheric circulation and palaeoclimatic investigations.
In order to use these water tracers “as tools” in the above listed disciplines, it is of major importance to have a proper understanding of their behavior in the water cycle. Our knowledge of the vertical distribution and the factors controlling the stable isotope ratios of oxygen -18 and deuterium in the atmospheric moisture is derived from observations and vertical profiles in the atmosphere.
An international programme jointly operated by the International Atomic Energy Agency (IAEA) and the World Meteorological Organization (WMO) has been conducting a worldwide survey of deuterium and oxygen isotopic composition of monthly precipitation since 1961. The result of which has been the development of a database dedicated to monitoring the isotope ratios of δ2H and δ18O in precipitation. The information derived from these databases is useful in understanding the spatial distribution of the stable water isotopes. A growing number of hydrological, forensic and ecological applications rely on this information.
The Namibian flood plains of the Cuvelai Etosha Basin are an ideal area of interest as they form part of a greater regional precipitation-recharge system extending all the way to Angola and since the study is regional as well as local. The results derived from this study will aid in better understanding the local isotopic distribution patterns in local precipitation and can also be used determine the geospatial origin of water.
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