Variation in the mean deuterium content of precipitations in Antarctica

Measurements recently carried out at the Services des Isotopes Stables at Saclay have made it possible to specify the variations observed in the mean isotopic composition of firn layers in Antarctica. It is known that the concentration of deuterium or oxygen 18 in accumulated snow varies geographically as a function of various parameters: distance from the coast, altitude, and mean annual temperature [Dansgaard, 1961, 1964; Dansgaard et al., 1969; Gonfiantini et al., 1963; Lorius, 1961, 1963; Merlivat et al., 1967; Picciotto, 1967]. The aim of the present study is to show the relationship between the mean deuterium content and the mean annual temperature. Values obtained for the deuterium content are reported in δ‰ with respect to SMOW, where δ‰ = [(R/R SMOW) - 1] 103 and R SMOW (atomic fraction) being considered as equal to 156.3 · 10−6. Samplings were carried out in Victoria Land (Victoria Land Traverse, 1960–1961), in Marie Byrd Land (Wisconsin Traverse, 1963–1964), in Adélie Coast, at the Soviet stations in Eastern Antarctica (Ninth Soviet Antarctic Expedition, 1963–1964), and in the vicinity of the South Pole, Byrd, and Scott bases (Figure 1). In this study we have taken into account only stations at which samples have been obtained that represent at least several years of snow accumulation, with the exception of the South Pole and Byrd bases, where the representativity of samples is not so good. Points representing at least 10 years of snow accumulation have been circled in Figure 2.