Removal of Aerosol Particles and Fractional Separation of HDO-H2O During Snowstorms

Abstract

The concentrations of both deuterium and water-insoluble particles in snow collected during snowstorms in the mountains of Colorado were found to be proportional to the size of snowflakes. Large snowflakes were associated with high particle concentration and high deuterium content. Small snow crystals appear to have originated in deuterium and aerosol-particle depleted air. The small snow crystals appeared at times of highest ice-forming nuclei concentration in air. The ratios of concentrations of different sized particles present in snow collected during a brief snowshower in March reveal that the predominant particles within small snow crystals are indeed those corresponding to the size range of ice nuclei. The relationship between the number of different sized particles present in a single snow crystal and the mass of snow crystals is given. Analyses of trajectories of moisture-bearing air parcels explained the large difference between the deuterium content of snow from the two snowfalls.