Simultaneous measurements of particulate elemental carbon on the ground observation network over the western North Pacific during the ACE‐Asia campaign

Abstract

The measurements of atmospheric aerosol and associated species have been carried out on the ground observation network over the western North Pacific as part of the Variability of Marine Aerosol Properties (VMAP) project. The network consists of four Japanese islands (Rishiri, Sado, Hachijo, and Chichi‐jima), ranging widely in latitudes from 25°N to 45°N along with the line of 140°E. In this paper, we report on simultaneous measurements of particulate elemental carbon (EC) on the four islands from March to May 2001, which cooperated with the Asia‐Pacific Regional Aerosol Characterization Experiment (ACE‐Asia) campaign, in order to characterize the outflow patterns of continental polluted air masses to the North Pacific. The mean concentrations of particulate EC in the four islands during this period ranged from 0.18 to 0.60 μg m−3. It is interesting to note that the temporal variations in the concentrations of particulate EC in Rishiri and Sado, which are located in the northern region of Japan (35°N–45°N), synchronized with each other. The EC concentrations in Hachijo and Chichi‐jima, located in the southern region of Japan (25°N–35°N), also showed similar temporal variations with each other but did not synchronize with those in Rishiri and Sado. These results demonstrate that the transport patterns of the polluted air masses from the east Asian continent to the northern regions of the northwestern Pacific are often different from those to the southern regions. It was also found that continental air masses are usually accompanied by pollutants over the southern regions but not over the northern regions of the northwestern Pacific.