Relationship between δD and δ¹⁸O values of falling snow particles from a separate cloud

Abstract

The relationship between δD and δ¹⁸O values (per mille deviation from SMOW) was investigated on falling snow particles from a separate convective cloud collected at 2 stations along a moving cloud trajectory. Observations were made in 1983 in Hokuriku, Japan and in 1985 and 1986 in Hokkaido, Japan. The δD and δ¹⁸O values of snow particles from a separate cloud were linearly related. The values of deuterium excess of observed δD-δ¹⁸O lines were much greater than 10 and differed with each case, while the slope was 8.5-9.6 in 7 of 9 cases.

Such observational results indicated that falling snow particles observed at both stations were produced in a cloud consisting of the air parcels containing initial water vapor having the same isotopic composition and that there was a possibility of kinetic effect in the sublimation process during growth of snow crystals.