Fog chemistry and droplet size distribution at Lake Mashu, northern Japan

Yamaguchi, Takashi*; Watanabe, Yoko*; Katata, Genki; Noguchi, Izumi*

The fog chemistry and droplet size distributions were observed at the somma of Lake Mashu during the summertime in 2012. Daily fogwater sample were collected by using an active string fog collector. Rainwater was collected for a week using bulk samplers. Both samlples were analyzed by an ion chromatography. During the midnight, fog droplet size distribution was also observed using an optical droplet monitor from 0:00 to 4:00 in local time. The mean concentration of total nitrogen ion in fogwater (NO+NH) was 5.4 times higher than that of rainwater. Observed highly acidified fog events suggested the effects of anthropogenic air pollution and volcanoes. In October, liquid water content of large fog droplets was clearly less than other months. This may be explained by the increase of sea salt particles transported from the Japan sea.