塩害に関する基礎的研究(第5報) ―海岸近くにおける強風時の海塩粒子の分布―

Abstract

Observations of the horizontal distribution of the number concentration of giant sea-saltparticles near the ground surface were carried out in the strong wind conditions at several stationslocated from the coast to the inland near Ogata, Niigata Prefecture, on Jan. 24, Dec. 13, and Dec.14, 1970.The wind from the sea ranged from 10 to 18 m/sec in speed in the lowest several hundredmeters layer. The observation showed that the particle number concentration near the grounddecreased with distance from the coast, as expected from our theory.The impaction-sedimentation ratio, γ, estimated from our present observation, is about 10 forthe wind of 10 m/sec, and about 13 for 16 m/sec.However, the impaction factor, λ, obtained from our observation, is rather smaller than butnearly the same order with that written in the previous report on the observations of the horizontaland vertical distributions for the weak wind.The particle number concentration observed at the coast is compared with data observed byToba et al. at the sea surface. The concentration at the coast for the variable wind speed is alsodiscussed.