Long range transport of aerosol over the North Pacific Ocean

Abstract

The investigation on long-range transport of aerosol particles over the North Pacific was performed using PIXE. Sampling was carried out on board a large sailing ship, T.S. “Nippon Maru”, during the cruise round the North Pacific from June 21 to August 31 in 1991. Aerosol samples were collected with two sets of Battelle-type 10 stage cascade impactors in parallel. Radon daughter concentrations were concurrently measured in order to obtain the time scale of air mass transport from continents using the half-life of radon (3.8 d). The data were compared with those obtained by the previous sampling cruises of R/V Hakuho Maru in 1985, 1989 and 1990. Anomalously high concentrations of fine sulfur (particle size < 1 μm) and silicon were observed around the northern part of the central North Pacific. Trajectories of air mass suggested that the increase of these components were caused by the big volcanic eruption of Mt. Pinatubo in the Philippine Islands on June 15, 1991.