塩害に関する基礎的研究(第4報) ―海岸近くにおける海塩粒子の分布―

Abstract

Observations of the horizontal distribution of the salt mass and the number concent-rations of giant sea-salt particles near the ground were carried out at 6 stations distributedfrom the coast to the inland near Ogata, Niigata Prefecture, on Dec. 6 through 8, 1968.The wind from the sea near the surface up to 1000 in level ranged from 2 in/sec to6 in/sec in speed. The observations showed that the particle number concentration atthe coast increased with wind speed from the sea, the particle number concentration nearthe gound decreased with distance from the coast, as expected from our theoretical model, and its value at 40 km from the coast was one order smaller than that at the coast.The impaction-sedimentation ratio, r, estimated from the observed horizontal distri-bution of the particle was about 20 for 6 m/sec in wind speed, about 10 for 4 m/sec, andabout 4 for 2 m/sec. The value of r for 6 m/sec is in good agreement with that estimatedin the preveous report from an observation of the three-dimensional distribution.