Abstract
On the basis of the isotopic analysis of deuterium content in snow crystals and graupel pellets which fell on the coast of Japan facing the Japan Sea, following results were obtained. (a) The D/H ratios of snow were large (mean value 150±2ppm) when the snow flakes consisted of non-rimed crystals having the same shape of crystal habit. (b) The D/H ratios were small (mean value 146±3ppm) when the precipitation consisted of graupel pellets, rimed crystals or a mixture of two different shapes of snow crystals. (c) It is likely that the difference between (a) and (b) was due to the difference in the vertical development of the precipitating clouds. (d) Temperatures of the sea surface from which water of snowfall had evaporated were estimated from the D/H ratio of snow samples. As the horizontal water temperature gradient in the Japan Sea was very steep, the geographic location of thisvapour source could be specified.
