Abstract
As a model of the drift of snow crystals and flakes, field experiments were carried out on drift and turbulent diffusion of paperlets emitted from aircraft. The size of a paperlet used was 2×2 cm. The paperlets fallen on the ground were collected by the citizens in Sapporo, and were returned to our laboratory. The experiments were carried out on February 1, February 28 and March 16, 1961. Fig. 10 shows the isopleths of the collected paperlets emitted at 450 m on February 28. Fig. 11 is for those emitted at 1800 m on March 16. The horizontal diffusion coefficient was estimated as the order of magnitude of 105cm2⁄sec, according to Sakagami's formula for an instantaneous point source.
